Onus v Telstra Corporation Limited [2011] NSWSC 33 (10 February 2011)

Last Updated: 26 May 2011

Supreme Court New South Wales

Case Title:	Onus v Telstra Corporation Limited
Medium Neutral Citation:	[2011] NSWSC 33
Hearing Date(s):	25 August 2010,2 September 2010,3 September 2010,7 October 2010
Decision Date:	10 February 2011
Jurisdiction:	Common Law
Before:	Price J
Decision:	(1) Defendant is restrained from erecting any structure over a height of 18 metres at the property at 33 McIntosh Street, The Oaks, in the State of New South Wales, 2570 being the land comprised in folio identifier 21/730754
Catchwords:	TORTS - quia timet injunction - whether intended height of Telecommunications tower a risk to safety of aircraft using plaintiff's airfield - whether public nuisance - whether plaintiff has standing - whether private nuisance - no emanation from defendant's land - whether substantial and unreasonable interference with plaintiff's land - extent of grant of quia timet relief
Legislation Cited:	Civil Aviation Regulations 1988 (Cth)
Cases Cited:	Attorney-General v PYA Quarries Ltd [1958] EWCA Civ 1; [1957] 2 QB 169 Coalcliff Community Association Inc v Minister for Urban Affairs and Planning [1999] NSWCA 317; (1999) 106 LGERA 243 Brodie v Singleton Shire Council, Ghantous v Hawkesbury City Council [2001] HCA 29; (2001) 206 CLR 512 Commonwealth ex rel v VonBestecki, 30 Pa. D. & C. 137 (Pa.Com.Pl. 1937) Elston v Dore [1982] HCA 71; (1982) 149 CLR 480 Hargrave v Goldman [1963] HCA 56; (1963) 110 CLR 40 Hunter & Ors v Canary Wharf Ltd [1997] 1 AC 655 Leichhardt Municipal Council v Montgomery [2007] HCA 6; (2007) 230 CLR 22 Manitoba (Attorney General) v Campbell (1983) 26 CCLT 168 McFadzean v Construction, Forestry, Mining and Energy Union [2007] VSCA 289; (2007) 20 VR 250 Melaleuca Estate Pty Ltd v Port Stephens Council [2006] NSWCA 31 Oakley v Simmons 799 SW 2d 669, (Tenn.Ct.App., 1990) R v Goldstein [2005] UKHL 63; [2006] 1 AC 459 R v Rimmington [2005] UKHL 63; [2006] 1 AC 459 Rickard v Allianz Australia Ltd [2009] NSWSC 1115 Robinson v Kilvert 41 ChD 88 Robson v Leischke [2008] NSWLEC 152; (2008) 72 NSWLR 98 Sedleigh-Denfield v O'Callaghan [1940] UKHL 2; [1940] AC 880 Southport Corporation v Esso Petroleum Co Ltd [1954] EWCA Civ 5; [1954] 2 QB 182 Sutherland Shire Council v Becker [2006] NSWCA 344 Thompson-Schwab v Costaki [1956] 1 All ER 652; [1956] 1 WLR 335 United Airports Co of California v Hinman (1940) US Av R 1
Texts Cited:
Category:	Principal judgment
Parties:	Grahame Dudley Onus (Plaintiff) Telstra Corporation Limited (Defendant)
Representation
- Counsel:	Counsel: J McCarthy QC with J O'Sullivan (Plaintiff) S Duggan SC with M McMahon (Defendant)
- Solicitors:	Solicitors: Lyons & Lyons (Plaintiff) Mallesons Stephen Jaques (Defendant)
File number(s):	SC 2010/260963
Publication Restriction:

Judgment

1. On 21 September 2009, the Wollondilly Shire Council (the Council) granted development consent for the installation of a Telstra Mobile Network Telecommunications tower (the tower) of a height not exceeding 35 metres at 33 McIntosh Street, The Oaks (the site). Telstra Corporation Limited (the defendant) intended to proceed with the installation of a 35 metre high tower on 6 August 2010 but Grahame Dudley Onus (the plaintiff) was granted an interlocutory injunction by Studdert AJ on 5 August 2010 which restrained the defendant from erecting any structure on the site over a height of five metres, until further order. The plaintiff now asks for the defendant to be permanently restrained from erecting the tower above five metres.
2. The plaintiff is the sole registered proprietor of the land known as "The Oaks Airport" located at The Oaks in the State of New South Wales, being the whole of the land in folio identifier 1/586257 (the airfield). It is the plaintiff's case that the proposed installation by the defendant of a 35 metre high tower in close proximity to his airfield is a threat to public safety and constitutes a public nuisance. Furthermore, he argues that the increased risk to aviation safety posed by the tower's installation creates a state of affairs the response to which he considers is reasonable and appropriate to direct that sections of his land cease to be used as an airfield and to prohibit certain pilot training activities from being conducted there. He submits that the proposed tower will interfere with his continued and traditional use of the land as an airfield and thereby constitutes a private nuisance. The plaintiff contends that the defendant has no justification or defence that its proposed installation of the tower is a reasonable use of the land, having regard to the proximity of the airfield and the availability of other sites for the tower in the area of The Oaks. He asks the court to grant a quia timet injunction.
3. A quia timet injunction is granted where there is proof that the apprehended damage is imminent, or likely to occur and unless the defendant is made to desist, there is a real probability of substantial damage to the plaintiff's land or comfort. The tower has been constructed to a height of 5 metres and but for the interlocutory injunction, the construction would have proceeded to the height intended. There is no issue in this case that the remedy sought is premature.
4. The defendant submits that the plaintiff has established neither a public nor private nuisance and is not entitled to the relief sought. A principal contention advanced by the defendant is that the evidence does not support a finding that the tower will pose a risk to aviation safety or that all aircraft and/or all trainee pilots will be at risk. Rather, the evidence discloses that in all but "exceptional cases" the tower will pose no interference with aviation safety or pilot training.
5. The plaintiff was represented by Mr J McCarthy QC with Mr J O'Sullivan and the defendant by Ms S Duggan SC with Ms M McMahon.
6. Before venturing further, it is convenient to detail the background facts, which are largely uncontroversial.

Background facts

7. The airfield has been in continuous operation as an airport since World War II. It was built between 1941 and 1942 as a base for fighters such as the Spitfire and bombers such as the B-24 Liberator and was originally designed to accommodate aircraft of up to 29,510kg but currently operates for aircraft only up to 5,700kg. It is a NSW State Heritage site. The Statement of Significance in the New South Wales State Heritage Inventory notes that the airfield "is of historic interest as one of many similar airstrips which were constructed during WWII but, unlike many others which have been abandoned, it has continued in use."
8. The airfield consists of three grass runways being two that run parallel in a North-South direction and one running East-West. The North-South runways are each 150 feet (approximately 45 metres) wide.
9. A wide variety of aircraft use the airfield, including twin turbine engine aircraft and twin turbine engined heavy helicopters operated by the NSW Police Department, NSW Parks and Wildlife Service and the military. The airfield is mostly used by light aircraft with single or twin engines with capacity to seat between two and six people and for pilot and instructor training including student solo flying and student dual flying. It is used by students of both powered aircraft and gliders, including gliders based at or having taken off from Camden airport. The airfield is also used by helicopters, balloonists and parachutists.
10. There are approximately 200 aircraft movements on average at the airfield per day. The plaintiff estimated that 80 per cent of the movements involve student pilots. A movement includes take-off, landing or a low flying pass. When training, it is usual for student pilots with their instructors to conduct numerous landing and take-off runs (a "touch and go"), to practise take-offs and landings. Students, pilots and instructors also conduct precautionary search and landing procedures at the airfield.
11. The airfield is not "controlled" and has no operational air traffic control tower. There are no instrument approach procedures at the airfield, which is open to all aircraft. No prior notification is required to use it and most aircraft arrive without prior notification.
12. Aircraft of all classes land at the airfield due to stress, mechanical problems or other causes. The airfield is the first place to land when coming into Sydney from the south or west. It is the nearest alternative airport to Camden or Bankstown.
13. The plaintiff purchased the airfield in 1975 in partnership with Jack Davidson whose interest he acquired in about late 2000. A manager (Mr Holden) who is in charge of the day-to-day operations of the airfield is employed on a part-time basis. Mr Holden is at the airfield about two or three hours a day but has other employment that is based at the airfield.
14. The airfield is uncertified and unregistered by the Civil Aviation Safety Authority (CASA). It is regarded by CASA as an "Aeroplane Landing Area" (ALA). CASA considers that it has no regulatory jurisdiction over ALAs but has produced guidelines which set out factors that may be used to determine the suitability of a place for the landing and take-off of aircraft which are contained in Civil Aviation Advisory Publication (CAAP) 92-1(1) Guidelines for Aeroplane Landing Areas .
15. The plaintiff plans to restore and redevelop the airfield. He is in the process of applying to have CASA certify the airfield as a "Registered, Non-Precision Approach, Code 3 Airport."
16. In March 2009 NGH Environmental prepared a Statement of Environmental Effects for the proposed installation of a mobile telecommunications facility on the site at the request of the defendant. The report stated that the proposal was intended to provide improved mobile phone coverage to the local area on the Next G network. The document assessed, inter alia , the environmental impact of the development.
17. On the site is the Volunteer Rural Fire Brigade building and an electrical substation behind that building. The Council is the owner of the land. The NGH report disclosed that four potential sites were considered for the proposed development and the site was the selected candidate because it was "anticipated to have a low environmental impact and likely to cause the least community concern". The site "also satisfied the Rural Fire Brigade requirements and will provide the necessary coverage for the target area". The report mentioned that the airfield was "located approximately 400m from the proposed site."
18. As various distances have been provided in the material in these proceedings between where the tower is to be located and the airfield, I propose to accept those detailed in the plan prepared by Abingdon Engineering Services (ex B, annex GO-4) as they were precisely measured. The tower is:

• 147.59 metres from the edge of the eastern runway;
• 223.52 metres from the centreline of the eastern runway; and
• 113.91 metres north of the runway threshold.

19. On 18 March 2009, NGH Environmental lodged a development application with the Council for the installation of the tower. It appears that an email headed CASA Approval 20 March 2009 was submitted to the Council on 20 March 2009. The email was sent from Leonard Yates, a flying operations inspector from CASA to Steve Collins of United Group Services on behalf of the defendant. The email included the following:

"The structure in its amended location, approximately 35 metres closer to the Oaks aerodrome than the original proposal, does not penetrate any of the recommended obstacle free areas or transitional surfaces defined in Civil Aviation Advisory Publication (CAAP) 92.1(1) 'Guidelines for Aeroplane Landing Areas' in relation to The Oaks aerodrome. CASA therefore does not consider the structure to be an obstacle and has no requirement for marking or lighting the monopole. You may, however, consider marking the structure in accordance with MOS Chapter 8 paragraph 8.10.2.6, from a duty of care viewpoint."

20. In a letter dated 14 August 2009 from Luke Pilichiewicz, a district aerodrome inspector from CASA to the senior development assessment planner with the Council, he advised that:

• the airfield was an ALA over which CASA had no regulatory jurisdiction;
• CASA had produced guidelines which set out factors that may be used to determine the suitability of a place for the landing and take-off of aeroplanes;
• these guidelines are in (CAAP) 92-1(1);
• the information in the CAAP is advisory only and there is no legal requirement to observe the details set out in the CAAP;
• experience had shown that, in most cases, application of the guidelines will enable a take-off or landing to be committed safely, provided that the pilot in command:

(a) has sound piloting skills; and

(b) displays sound airmanship;

• from the information provided, the tower is located outside the area in figure 1 - Transitional Slope in the CAAP, therefore "there is no infringement of desirable clearance area";
• CASA does not approve or disapprove applications and does not undertake assessments unless there is a regulatory need established under CASA regulations;
• The Council should determine any safety deficiencies relating to the aerodrome with its current type of use and the location of the proposed tower from the guidelines.

21. The development consent granted by the Council required the tower to be marked "in accordance with the requirements of the Manual of Standards (MOS) (Chapter 8, par 8.10.2.6) of the Civil Aviation Safety Authority".
22. A report entitled Aeronautical Impact Study prepared by the Ambidji Group Pty Ltd dated 8 September 2009 had been submitted to the Council. The report was prepared upon the defendant's instructions "to assess the feasibility, in terms of the potential impact to aircraft and airport operations, of constructing a mobile network mast" at the site. The report concluded that the construction of the tower "with a maximum height above ground level of 35m (115ft) would not be assessed as a hazard to the safety of aircraft operations in the area".
23. The tower is of solid construction and has been marked in compliance with MOS (Chapter 8, par 8.10.2.6). It has been painted in "aviation red" and white. Exhibits 2 and 3 are photographs of the tower.

The plaintiff's evidence

24. The plaintiff is a licensed flight engineer and pilot. He obtained a pilot's license at about 19 years old and worked for Qantas as a flight engineer for approximately 25 years. He was employed after 1995 by other airlines including Air Pacific and Air Atlanta Icelandic. He retired in March 2010 having accumulated approximately 16,000 flying hours. He disagreed with the conclusion of the authors of the Ambidji report that the tower will not impact upon flying operations at the airfield. He stated (ex B, par 42):

"If the Tower is erected, I intend to take the following steps because I believe them to be necessary to appropriately manage the additional risks created by the Tower.

(a) I would permanently close the Eastern runway. I understand it to be both unsafe and illegal to operate two parallel runways simultaneously at an uncontrolled airport. However, as the runways are grass, it is necessary to let them lie fallow several times a year as otherwise they become churned up with constant use. If the grass is not given the opportunity to regrow, the surface of the runway becomes increasingly broken and eventually, hazardous or unusable. Accordingly, my current practice is to alternate between using the Western and Eastern runways, allowing one to lie fallow and recover whilst the other is in use. If the Tower is erected and I permanently close the Eastern runway, it will be necessary to close the Airport several times each year to allow the Western runway to lie fallow. I would therefore not be able to obtain revenue from landing fees and for use of Airport facilities whilst the Airport is closed.

(b) To the extent that it is within my power, I would prohibit and advise against all flying to the East of the Airport in the vicinity of the Tower.

(c) To the extent that it is within my power, I would prohibit and advise against all precautionary search and landing training at the Airport.

(d) I would close the airport at times of high Westerly winds.

(e) I would advise my insurer of the erection of the Tower and provide it with a copy of the expert evidence filed in these proceedings. I anticipate that my insurance premiums would increase as a result.

(f) I would cease any further work to redevelop the Airport in accordance with the "Masterplan" annexed to this affidavit and withdraw my application to CASA for the Airport to be formally certified as a "Registered, Non Precision Approach, Code 3 Airport" as I do not believe CASA would grant such approval if the Tower is erected.

(h) If as a result of the steps outlined above the Airport operated at a substantial loss, I expect that I would close the Airport permanently."

25. In cross-examination, the plaintiff agreed that he had formed the opinion that he would need to take the steps identified in par 42 as he understood that all aircraft using the airfield "would be at serious risk of coming into conflict with the Telstra mast": T121.7-10.
26. I should mention that Kevin Moore expressed some scepticism in par 61 of his affidavit as to whether the airfield's runways would qualify as Code 3. The plaintiff, however, was not cross-examined about his plans to redevelop the airfield and I give little weight to Mr Moore's views on this issue.

A risk to air safety?

27. The expert testimony in the hearing was advanced by Bob De La Hunty OAM, Stephen Tizzard and Kevin Moore. Mr De La Hunty's affidavit is ex C and Mr Tizzard's is ex A. Mr De La Hunty's credentials which are revealed in ex C, annex A include being president and chief pilot of the Historical Aircraft Restoration Society Inc and being licensed as a commercial pilot since 1983 with more than four thousand flying hours. Mr Tizzard's career biography is detailed in ex A, SKHT-1. He is the chief executive officer of Recreational Aviation Australia Incorporated and first obtained a private pilot's license in about 1965. He authored CASA Guidelines For Aeroplane Landing Areas (CAAP 92-1(1)). As a civil flying instructor, his instructing has involved some eight thousand hours, which included "all light aircraft": T26.2. He is now a Recreational Aviation Australia senior instructor. Mr De La Hunty and Mr Tizzard gave evidence in the plaintiff's case.
28. Mr Moore's affidavit and annexed curriculum vitae outline that he is a senior aviation consultant with nearly forty years experience in the development of aviation standards and recommended practices and in the safety regulation of international civil aviation. His employment with CASA and the Department of Civil Aviation included the position of General Manager, Airways and Airspace Branch located in Canberra. Mr Moore is currently endorsed to fly heavy aircraft but has not flown light aircraft for over twenty years. His 7,500 flying hours have mostly been flown as pilot in command under the instrument flight rules. He gave evidence in the defendant's case.
29. I propose to provide here my assessment of the evidence of the experts. Although there was the occasional overstatement by them, I found that the opinions expressed by Mr De La Hunty and Mr Tizzard were soundly and realistically based upon their extensive experience. On the other hand, I consider that Mr McCarthy's criticism of Mr Moore's opinions as not reflecting what happens in the "real world" was to some extent justified. Little weight (if any) was given by Mr Moore in his risk assessments to the role that factors such as inexperience, inattention, stress and unforseen events might play in a light aircraft accident. His opinions manifested, it seems to me, his somewhat bureaucratic background in heavy aircraft and lack of recent experience with light aircraft. To my mind, the reliability of some of the opinions he expressed was thereby undermined. In general, I had more confidence in the views of Mr De La Hunty and Mr Tizzard.
30. Central to the plaintiff's case is the claim that the tower will pose a risk to air safety. Whilst the defendant concedes that the tower will interfere with aviation safety in exceptional cases, the defendant contends that any such risk is so remote as to be no real risk at all. In closing written submissions, the defendant argued at pars 12 and 13 that:

"The evidence of the plaintiff taken at its highest limits the potential interference to student pilots undertaking the following training manoeuvres:

(a) An instructor simulates an engine failure on a downwind (left hand) circuit of the runway 18 (ie the Eastern runway) and the trainee attempts to land on that runway.

(b) A student or inexperienced pilot (dual or solo) conducting a precautionary search on Runway 36 (Eastern) commencing the climb at the end of the low pass will hit the mast as a combination of application of power resulting in a heading change and loss of height raising flaps too quickly.

(c) When a pilot under test conditions is conducting a precautionary search and landing with a South West wind blowing elects to set up the procedure using a right hand circuit on Runway 18 (left) to avoid overflying the hangar area, doing the inspection run East of Runway 18 (left).

This evidence of Mr Tizzard was qualified in cross-examination such that it was accepted that these events would not of themselves give rise to a risk of interference. Rather, in order for the risk of interference to arise the following factors were required to be in place:

students who are in the company of an instructor undertaking either a simulated emergency or a precautionary search and landing where the student and the instructor:

both are not familiar with the Oaks airport (i.e. first visit for both the student and instructor); AND

both fail to identify the Telstra Mast on both of the two high level flights over the field before undertaking the abovementioned manoeuvres; AND

move into the path of the Telstra Mast at low level; AND

forget the Telstra Mast is there or fail to see it when approaching it flying at low level."

31. The defendant's restriction of the risk to the scenarios referred to in paragraphs (a)-(c) of its closing submissions appears to be founded upon what was stated by Mr Tizzard in his affidavit at par 39. Mr Tizzard, however, did not confine the hazard posed by the tower to the three scenarios but advanced them "by way of illustration". He concluded that there were "almost innumerable permutations of circumstances that could result in the tower posing a hazard to aviation": ex A, par 39. Mr Tizzard believed that the tower would pose a serious risk to air safety.
32. Mr De La Hunty was of the opinion that the tower represents "a clearly foreseeable threat to air safety and would deter any prudent pilot from using the Airport": ex C, par 37. Mr De La Hunty, on this occasion, overstated the extent of the deterrence that the tower will pose to aviators. In cross-examination, he agreed that the presence of an obstacle outside the obstacle-free area would be a concern but a prudent pilot would not be deterred from landing at the airfield because of the tower.
33. Mr Moore did not believe that the tower represents a threat to air safety.
34. All of the experts who gave evidence agreed that the tower does not fall within the "obstacle free area" as defined in CAAP 92-1(1). An "obstacle free area" means:

"there should be no wires or any other form of obstacles above the approach and take-off areas, runways, runway strips, fly-over areas or water channels."

35. It was common ground that the tower did not intrude into any of the areas described in Figure 2B CAAP 92-1(1), par 5.5.
36. As the magnitude of the risk is controversial, it is necessary to consider the circumstances that the plaintiff claims could result in the tower being a risk to aircraft.

Emergencies

37. Emergencies may arise in aviation operations for diverse reasons. Aircraft may then be required to undertake emergency landings or the emergency itself may arise during the landing procedure. An emergency may also arise on take-off.
38. Regulation 157(1) Civil Aviation Regulations 1988 (Cth), which prohibits the flying of an aircraft at a height lower than 1,000 feet over a populous area or lower than 500 feet over any other area, does not apply when it is essential that a lower height be maintained "through stress of weather or any unavoidable cause." It is apposite to note that the minimum flying height restrictions also do not apply to pilots engaged in flying training or in a baulked approach procedure, or the practice of such under supervision of an instructor or check pilot or in the course of actually taking-off or landing.
39. Mr De La Hunty opined that during an emergency landing, the pilot would "possibly" be able to identify and avoid the tower but that would depend on the level of emergency. He explained that in some emergencies involving an engine failure, the control of the aircraft is extremely difficult. Actual engine failure on take-off or landing would give rise to the highest concern. The primary goal in an emergency is to land safely.
40. Mr De La Hunty's evidence on this topic during cross-examination included the following (T93.46-50 - T94.1-49):

"Q. I'm asking you only about actual emergencies?

A. In an actual emergency, the training is given to keep the aircraft straight.

Q. So it would be fair to say would it not, MrDeLaHunty, that in relation to actual emergencies with a take-off towards the north there is a very minor prospect, if any at all, of the plane coming into contact with the Telstra mast?

A. No, I disagree with that.

Q. It would only be those pilots who were unable to perform the manoeuvre as they had been trained and had practised during their certification periods?

A. Typical light twin aircraft are at a very critical phase of flight until they are cleaned up, wheels up, flaps up. If they suffer an engine failure and malfunction they tend to have a sink rate rather than a climb rate until they are cleaned up.

In the event of after aircraft taking off to the north experiencing particularly an engine failure on the righthand, the left engine would be trying to pull the aircraft around to the right and it would not be unusual to find a pilot outside of the ideal heading that they are trained to do, depending on the, a lot of things; wind, the performance of the aircraft, the configuration at the time.

Q. But it would be unusual to find the pilot almost 200 metres outside that desired heading in that circumstance in light of his training?

A. No. In my experience I've seen pilots divert significantly and the time that the instructor

Q. We are not talking about students at the moment, actual emergencies?

A. Actual emergencies. Just repeat the question again, I'm sorry.

Q. In actual emergencies, and I will come to simulated emergencies, you would accept that whilst a pilot may need to correct when an engine goes out on a dual engine aeroplane it would be unusual for an experienced pilot to I can't remember the words used but to move more than 200 metres away from the desired line of takeoff, or not more than, up to 200 metres?

A. There are many experienced pilots who are dead now, having gone further than that distance. I can cite those places if you wish.

Q. The pilot is still in charge of the aircraft and capable of steering the aircraft with a single engine failure, correct?

A. Only if all the parameters within the operation of the aircraft are clear.

Q. I don't understand that, MrDeLaHunty. You may need to explain that a little more carefully?

A. Would you like a technical explanation? Would that help?

Q. It would probably be better if you use one that is simpler than technical?

A. There is what is called a blue line speed which is a speed that the pilot should be able to maintain directional control in the event of an emergency if he can maintain that blue line speed. That blue line speed does not mean the aircraft will climb. Depending on the configuration, it may be descending. If you can't maintain that blue line speed it is into a situation where the live engine is turning the aircraft in a direction of the dead engine and in that situation the pilot tends to have no control and will lead to a crash, or you cannot manoeuvre it around terrain."

41. When it was put to Mr De La Hunty by Ms Duggan that the only way his scenario could occur would be if the engine failure occurred somewhere over the existing runway at a height below 32 metres where the plane veers off and hits the tower, Mr De La Hunty testified as follows (T99.7-31):

"A. The additional situation that can happen is that pilots frequently try and turn back and in that event again a teardrop turn to come back to the field may in fact bring you in conflict with the mast.

HIS HONOUR

Q. What is a teardrop?

A. If I can just use my hands, your Honour. The aircraft is airborne, retracting the gear, has an engine failure, has gone past where the mast is and the pilot has aan emergency and this could be in a single engine aircraft or a twin engine aircraft. He thinks he is high enough to be able to get back to the airfield and will initiate a teardrop turn to come back.

DUGGAN

Q. And that's generally to the left, is it not?

A. No, it will be whatever takes to get the aircraft back on the ground.

Q. So again it requires a coincidence of events that are quite specific and particular in order for your scenario to occur?

A. Yes.

Q. And if any of those particular circumstances aren't occurring simultaneously, then the event is unlikely to occur?

A. Obviously."

42. Unsurprisingly, Mr De La Hunty was of the opinion that an emergency, depending on its severity puts a lot of strain on the pilot, particularly in a single pilot twin-engine operation. There was usually a "chain of events" that led to an accident. Mr De La Hunty stated that the tower was well within the aircraft "circuit area" especially in emergency situations caused by "stress of weather" or engine malfunction or whilst conducting procedures such as a precautionary search before landing.
43. Mr Tizzard annexed to his affidavit a diagram that illustrated some of the flight paths that an aircraft could take to reach The Oaks runway in the event of engine failure or other emergency: ex A, SKHT-6. He therefore believed that a pilot dealing with an emergency could readily enter the airspace occupied by the tower.
44. On the other hand, Mr Moore considered that the likelihood of an encounter with the tower by a twin-engine aeroplane that has experienced a failure of the starboard engine during take-off to the north from the eastern parallel runway was low. This opinion was based upon the training of pilots of multi-engine aircraft to control the aircraft's direction immediately after an engine failure and the testing of their ability to do so before being recommended for endorsement to fly the aircraft as pilot in command. Mr Moore stated that pilots who are being trained to fly multi-engine aircraft initially may not be able to fully control the swing associated with failure of an engine after take-off but the instructor or check pilot conducting the training "should never allow a dangerous situation to develop": T139.35-36.
45. In answer to a question about a pilot flying solo for the first time or shortly thereafter, Mr Moore replied (T144.10-13):

"A. For the first time in an aeroplane which he has just been authorised to fly, he should be well and truly familiar with the behaviour of that aeroplane and able to cope with an engine failure should it eventuate. Because he has just been trained on the aeroplane so all of that training will be fresh in his mind."

46. Mr Moore pointed out that the tower was not within the potential flight path of aircraft flying in the circuit area of the airfield unless a pilot was flying lower than 500 feet above ground level. Although that is to be accepted, it was the evidence of Mr Tizzard and Mr De La Hunty that flight below that height might occur during emergencies, baulk approach procedures and pilot training.
47. As to emergency landings, Mr Moore testified that "in most emergency situations, the pilot is in a position to plan the operation of the aeroplane up to the point of a safe landing because he's got time to do it": T147.19-21. Mr Moore said that the pilot would manoeuvre the aircraft as rapidly as he possibly could to line it up for a landing on whatever runway was available. If he happened to turn towards the tower, the pilot must be able to see the tower because it is marked and he would not hit it, as he knows it is there. Mr Moore agreed that in some circumstances such as fire the pilot would not have the time to carefully examine the route and plan a response to the emergency.
48. Mr Moore's sanguine assessment that the tower's presence was unlikely to cause a hazard in emergency situations was founded upon the pilot's (or instructor's) training, the ability of that person, because of his training, to react to the circumstances of the emergency and to see and avoid the tower. Mr Moore's answer quoted at [45] above reflects the little weight that Mr Moore gave to the strain that an unexpectedly dangerous event might place upon the person who is in command of a light aircraft and to the level of pilot experience. Furthermore, Mr Moore's assessment does not appear to take into account that an inexperienced pilot dealing with an emergency may be distracted from keeping a lookout for the tower. I prefer and accept Mr De La Hunty's pragmatic assessment that during some emergencies the tower will pose a threat to air safety at the airfield. I have no difficulty accepting his opinion that the tower may be within the circuit area in emergencies and some procedures such as precautionary search and landings.

Precautionary search and landing

49. There was much debate in the course of the testimony of Mr Tizzard and Mr Moore as to the danger that the tower will pose to pilots undertaking a precautionary search and landing either during an actual emergency or landing procedure particularly when the pilot is unfamiliar with the airfield or in the course of emergency training.
50. Mr De La Hunty explained that a precautionary search and landing procedure is undertaken by a prudent pilot intending to land at a non-controlled airport so as to ascertain that the runway is free of obstruction and has a suitable landing surface. The procedure is also used by pilots training to land on surfaces other than on runways, such as fields or roads, as occurs in the Australian outback and elsewhere.
51. In his affidavit Mr Moore recounted at pars 32 and 33:

"It will not affect the conduct of training in precautionary landings because the flight path of an aeroplane during the conduct of a correctly performed inspection of the intended runway is unlikely to bring the aeroplane into conflict with the mast. To do so the aeroplane would have to be positioned about 180 metres to the side of the runway centreline, too far away for a close inspection of the runway surface by the pilot. This is particularly true for an inspection conducted at a height below the level of the trees near the aerodrome. Apart from making the inspection of the runway surface condition difficult it would also introduce obstacles such as trees to the flight path, requiring the pilot to concentrate on obstacle avoidance rather than assessment of the runway surface.

Having inspected the runway the pilot carries out a precautionary circuit in which the aircraft is positioned on the downwind leg at a greater height consistent with remaining clear of cloud and obstacles, and at a distance from the runway that enables the pilot to maintain visual contact with the runway while manoeuvring the aircraft onto final approach without using large angles of bank that may cause the aircraft to stall. The mast could be between the runway and the downwind leg of a right hand precautionary circuit for a landing into the north on the eastern runway...However, its conspicuous marking and shape would enable a pilot to identify it as an obstacle during the runway inspection and to manoeuvre to avoid it. The mast may be useful as a training aid to demonstrate that obstacles can exist at low level within the circling area of an aerodrome."
And at par 37:

"Although the mast is within the circuit area for the eastern parallel runway, its presence is unlikely to cause a hazard in emergency situations such as precautionary approach and landing due to stress of weather or failing light or reducing visibility for the reasons given in paragraphs 32 and 33 of this affidavit."
The route outlined in annexure R to Mr Moore's affidavit was described as being a typical circuit pattern of the airfield.

52. The evidence disclosed that a precautionary search and landing normally involves three flyovers, the first two being conducted at higher levels and the third at a height between 200 feet and 50 feet. It is apparent from Mr Moore's testimony that during a "correctly performed" precautionary search and landing, the tower could be between the runway and the downwind leg of a right hand precautionary circuit for a landing into the north on the eastern runway. Mr Moore, however, was confident that the tower would be identified by the pilot and avoided.
53. Although Mr Tizzard agreed that a purpose of the first two flyovers was an attempt to identify any potential obstacles before the lower run was made, he did not share Mr Moore's expectation that a collision with the tower would not occur. His evidence during cross-examination on this topic included the following (T55.38 - T56.14):

"Q. I think you said to me I put 200 and you said somewhere between 200 and 50 feet?

A. Yes it would be the height.

Q. In order for that manoeuvre to pose a risk to the pilot in relation to the Telstra mast, the pilot would have had to have not identified it in either of his first two flyovers. Because there is no way a reasonably competent pilot would undertake manoeuvre which would bring him into conflict with the Telstra mast if he had identified that before he did his low level flying, correct?

A. Unfortunately no ma'am, people hit obstacles they know about.

Q. I asked you to assume a reasonably competent pilot?

A. I am assuming a reasonably competent pilot.

Q. But if the pilot has identified the obstacle he knows it is there and he will do whatever he has to do to avoid it and that may mean not going down to 50 feet but rather staying above the height of the obstacle for the purpose of doing this precision search landing?

A. Yes on the basis he doesn't get distracted that is a reasonable

Q. So with respect to this element of your concern, not only would it require this precision search landing manoeuvre to occur in order for Telstra mast to be a risk but the Telstra mast would only be a risk if two other circumstances occurred simultaneously with that manoeuvre, the first being the pilot has made a determination to go below 200feet and secondly the pilot has either failed to identify the Telstra mast or having identified it ignored it?

A. Or forgets about it under pressure yes."

And further (T59.15 - T60.10):

"Q. So the prospect is, in relation to flight instructors that are instructing students in this manoeuvre in this locality that provided the student is not the first of his students he will be familiar with this landing area?

A. That would probably be a reasonable assumption your Honour.

Q. And it would also be a reasonable assumption that he would have seen and identified the Telstra tower as being a potential obstacle?

A. I'm sorry, I couldn't agree with that.

Q. That is on the basis that you suggest, that notwithstanding the two circuits that he has done with his student and many other circuits he has done with other students, he has failed to identify a mast which is painted bright red and white bright orange and white or bright red and white. Is that what you are suggesting, MrTizzard?

A. Sods law, if it can happen it will happen, and that's my concern."

54. Mr Tizzard said that he was worried about a crosswind where the aircraft was pointing one way and "it is going the other way into the tower or turbulence": T57.18-20. He described this situation as being normal, but he would expect an experienced pilot to be aware of it and to take it into account. He said that does not always happen.
55. In his affidavit, Mr Tizzard stated at par 17 that during the inspection run of a precautionary search, it was difficult to predict how far the aircraft would be flown from (and parallel to) the landing direction because of visibility considerations (high or low wing aircraft) and pilot technique. During cross-examination, he said that if the aircraft was low wing "you might have to fly further out and be doing the inspection not immediately down in front...but with your line of vision past the wing tip": T55.7-8. He agreed that the goal of the pilot was to be as close to the runway as possible.
56. As I have recounted at [42] above, Mr De La Hunty considered that the tower's presence within the aircraft "circuit area" included precautionary search and landings. He noted that as a pilot flying a circuit as part of a precautionary search before landing is trained to look out of the aircraft and down at the runway to check that the runway is free from obstruction, the danger of collision arises as the pilot would not always be looking straight ahead (ie, at the tower) when flying the circuit.
57. It is necessary before assessing the competing opinions of the experts to shortly dwell upon evidence which concerns the visibility of the tower. Mr Tizzard disagreed with Mr Moore's assessment that the tower is unlikely to cause a hazard because it is conspicuously marked. There was no dispute, however, that the tower had been marked in accordance with the MOS (Chapter 8, par 8.10.2.6). Mr Moore at par 20 of his affidavit said:

"...on this basis I have formed the opinion that a pilot approaching to land towards the south on the eastern parallel runway in flight visibility conditions of at least 5,000 metres required for flight under the Visual Flight Rules would notice the mast due to its conspicuous marking."

And at par 43:

"A pilot approaching to land on runway 18L at The Oaks in flight visibility conditions of less than 5,000 metres is also likely to identify and avoid the mast because its obstacle marking is designed to make it conspicuous under a range of light and visibility conditions including those associated with low cloud and rain."

58. Mr Tizzard expressed the opinion that notwithstanding the tower's marking, it would be difficult to see in some circumstances such as poor light or visibility or with the sun behind it. Furthermore, it would be difficult to see at typical aircraft closing speeds "because of its slim profile and because it stands in isolation rather than as part of a visually distinct line of trees or buildings": T151.46-48.
59. Although Mr Tizzard said in his oral testimony that he had not made any assumptions about the tower, it appears that he believed it would be "skeletal" so that it would have voids that could be seen through. He agreed in cross-examination that if the tower was of a solid construction, it would be easier to see. Notwithstanding this agreement, he did not resile in cross-examination from those circumstances during which he considered the tower's visibility to be problematic.
60. Mr Moore responded to Mr Tizzard's opinion by pointing out that the red marking which is used was an "aviation red" which was designed to be conspicuous in poor light or visibility and stood out better against a dark grey background than against a light bright sky. When addressing the question of the sun being behind the tower, he replied (T152.30-32):

"...the situation where the sun is behind, well, so is anything but that doesn't alter my opinion about the relative risk of the mast being there because everybody will know about it, won't they." (underlining added)

61. It is plain from this answer that Mr Moore agreed that the tower will be difficult to see when the sun is behind it. However, not all pilots will be aware of its presence. Furthermore, those pilots who are aware of the tower's existence in the vicinity of the airfield may not be able to see it because of the position of the sun. I do not accept Mr Moore's assessment of the risk that the tower poses when the sun is behind it.
62. During cross-examination, Mr Moore accepted that pilots of small aircraft from time to time get caught out by weather and depending upon how heavy the rain was, visibility could be limited. He agreed that "in the middle of a downpour associated with thunderstorm", the tower with its marking may not be very prominent. In re-examination, Mr Moore emphasised that a pilot in such a situation would not be flying in accordance with the flight visibility conditions of at least 5,000 metres required for flight under Visual Flight Rules.
63. As to Mr Tizzard's opinion that the tower would be difficult to see as it stood out in isolation, Mr Moore disagreed. He said that as the tower was on its own "it stands out for all to see": T152.39-40.
64. Mr De La Hunty supported Mr Tizzard's evidence. He expressed the opinion that the tower would be difficult to see at a typical closing speed of 150 km per hour, given its slim profile and because it stood in isolation. It was not, he stated, part of an easily identifiable line of trees, buildings or other obstructions that could be readily seen and avoided. He pointed out that "in early morning or late afternoon, the Tower would be very difficult to see with the sun behind it or in low light or poor visibility due, for example, to smoke from bushfires": ex C, par 14. During cross-examination, he accepted that the tower had been appropriately marked so as to identify it as an obstacle, but testified that how easily the colours would be able to be seen depended on the light. When asked by Ms Duggan (T88.34-41):

"But from your practical experience even in low light they are still able to be seen?

he replied:

"Not always ...Depends on the background light. "

65. I do not accept Mr Moore's opinion that the presence of the tower is unlikely to cause a hazard. Notwithstanding the tower's conspicuous markings, I find that from time to time the tower will be difficult for a pilot to see due to prevailing conditions such as the position of the sun or heavy rain.
66. On reviewing the expert testimony on the issue of precautionary search and landings, I have concluded that the answer lies somewhere in between the optimism expressed by Mr Moore as to the unlikelihood of the tower causing a hazard and Mr Tizzard's strong disagreement. Whilst I find that in the majority of precautionary search and landing procedures, the tower is unlikely to cause a hazard, there will be occasions when its presence within the circuit area will present a threat to air safety whether arising singularly or in combination with emergency, inattention, unforseen circumstances, weather conditions or sudden evasive actions undertaken at low altitude.
67. Furthermore, I accept Mr De La Hunty's opinion that even if a pilot saw the tower in time to avoid it, measures taken to avoid the tower could result in an aircraft crashing because of sudden evasive manoeuvres performed at low altitude.

Baulked Approach

68. Mr De La Hunty stated in ex C, par 32:

"An aircraft on final approach to land may be forced to divert for reasons other than engine failure. For example, if an aircraft is landing to North and aircraft preparing to take off enters the runway from a holding area, the landing aircraft would be forced to divert. In such a case, the standard procedure is to divert to the right and then fly a circuit around the runway, directly into the airspace occupied by the Tower . Pilots are trained to divert away from the path of the runway, rather than simply pull up and fly down the runway. This is to avoid the risk of collision with an aircraft that may be taking off directly underneath the landing aircraft." (underlining added)

69. Mr Moore accepted what was stated by Mr De La Hunty at ex C, par 32. Mr De La Hunty, in his oral evidence, said that the "decision point' when a pilot decides to land or not may be made at any altitude. He disagreed with the proposition put to him by Ms Duggan that the decision point in relation to a landing was 500 feet above the ground.
70. During cross-examination Mr De La Hunty's testimony included the following (T102.24 - T103.11):

"Q. Yes, there would be options. Now, in relation to a baulked landing where the person just makes the decision that they are not ready to land for whatever reason, there is no interference with another plane taking off, the mast isn't going to be a matter of particular concern for that manoeuvre?

A. No.

Q. So the only point at which it would become a concern is if the person decided to abort the landing at a point at which if they turned to their left they may come into contact with the Telstra mast?

A. Yes.

Q. And the types of situations you are thinking of are situations where the pilot is still in control of the aeroplane?

A. Yes.

Q. And the pilot is still on the lookout for obstacles?

A. Yes.

Q. So effectively in relation to a landing procedure, it would only be a concern if somebody directly turned towards the Telstra mast and failed to identify it as an obstacle?

A. Yes.

Q. And they had to be at a height below 32 metres?

A. Yes.

Q. And I put it to you, MrDeLaHunty, that in light of the size, shape and colouring of the Telstra mast, that it would be an extremely unlikely event for those circumstances to arise simultaneously?

A. Maybe.

Q. Well, that's the likelihood is that a pilot would see this mast and not fly directly towards it?

A. Yes.

Q. So to the extent that you have raised a concern about landings, you accept that is an extremely remote concern?

A. Remote."

71. Whilst it might be remote that the tower would not be seen by a pilot in such circumstances, the possibility remains that it would not be identified if the sun was behind it or the baulked approach was conducted in heavy rain.

Turbulence and Crosswinds

72. The flight path of an aircraft may be affected by atmospheric and meteorological conditions and a deal of evidence was devoted to the impact that turbulence and crosswinds, which Mr Tizzard described as normal occurrences, might have upon aircraft flying in the vicinity of the tower. He expressed the opinion that an aircraft flying above the height of the tower might be at risk of colliding with it if there were turbulent conditions.
73. Light aircraft are more responsive to turbulence, Mr Moore testified, because of their low wing loading, which meant that a light aircraft could be deflected from the flight path "a little bit more than a heavy aeroplane": T168.11. The extent of the deflection depended upon the severity of the turbulence encountered. Mr Moore gave evidence that in severe turbulence there might be situations where the pilot may have difficulty controlling the aircraft. In fact "there may be situations where the control of the aeroplane is outside his capability for moments or longer periods of time": T168.20-23. He went on to say (T168.24-36):

"A light aeroplane encountering severe turbulence such as associated with very strong convective activity may be temporarily outside the ability of the pilot to control because the vertical behaviour is so strong. In moderate or light turbulence the same may not be true, is unlikely to be true because the aeroplane is still controllable.

The extent to which it will deviate vertically again is dependent upon the severity of the encounter and the ability of the pilot to control the aeroplane. However, there may be situations even in moderate turbulence where, if the pilot is a little slow let's say, or not physically strong enough to manipulate the controls as he needs to do to maintain the flight path then the aeroplane may deviate vertically to a significant extent. By significant I mean 20, 30 feet, perhaps more if the pilot is a little bit slow."

74. Mr Moore said that turbulent conditions were more likely to be encountered in the region of the airfield during the summer months in the afternoon. Turbulence generally operated on the vertical movement of the aircraft. Whilst the potential turbulence might be avoided if it was visible, Mr Moore said (T169.41-44):

"The thermal activity that I just described is not always visible and encounters with turbulence can be entirely unexpected because the source may not be readily apparent."

75. I conclude that the tower has the potential to create a risk to a light aircraft flying in its vicinity, which encounters severe and to a lesser extent moderate turbulence. This will particularly be so if the pilot is inexperienced and performing a circuit below 200 feet but above the height of the tower.
76. Another hazard posed by the tower is to aircraft operating from the airfield in strong crosswinds. Mr De La Hunty considered that strong westerly winds could result in an aircraft traversing the air space occupied by the tower. Mr Tizzard expressed his concern about a crosswind when "you are pointing the aeroplane one way and it is going the other way into the tower": T57.18-19
77. Mr Moore discussed horizontal movement and "windshear". Windshear can be predicted at major airports by the use of modern technology that the airfield does not possess. Mr Moore said that windshear cannot be seen but pilots know when to expect it and are trained about it. He said, however, that a pilot will not be sure if windshear will be present or not.
78. I find that the tower has the potential to create a risk to a light aircraft flying in its vicinity at a low level which experiences strong crosswinds or windshear. Once again, I consider that the risk will be enhanced when the pilot is inexperienced.

Pilot training

79. The airfield's role in pilot training is of importance in assessing the tower's potential risk to aviation safety. The airfield is predominantly used for student pilot and instructor training. An estimated 80 per cent of aircraft movements involve students. In particular, the airfield is used for training pilots in emergency sequences and low flying for general, recreational and acrobatic aviation. Such training includes simulated engine failures, low altitude stalls, baulked landing approach and go-around procedures and precautionary search and landings. It appears that precautionary search and landings cannot be conducted at either Camden or Bankstown and the airfield is the sole airport within the Sydney region where this procedure may be practised.
80. Mr De La Hunty opined (ex C, par 20):

"Flight training requires the consideration of additional safety margins and requirements that distinguish it from general aviation...Naturally, training situations may pose risks additional to those present during "normal" flying operations. For example, in simulating an engine failure on take-off in a twin engine aircraft, the instructor will suddenly reduce the throttle of one engine to zero and the student will have to react accordingly. Qualified pilots and instructors are also required to undergo regular checks in order to keep their licenses. Flight training and checking of qualified pilots or instructors may require going beyond "safe" limits to gauge the subject's reaction to an emergency. Accordingly, checking of qualified pilots and instructors may be undertaken close to the operational limits of aircraft with a corresponding increase in risk."

81. Mr Moore considered that going beyond safe limits during training and checking flights was never justified but he did not disagree that additional safety risks may arise during pilot-student training. He was of the opinion, however, that any additional risk would be managed, as the student pilot would be under the supervision of a flight instructor. For instance, in the event of unsatisfactory directional control at low level by a trainee at the time of a simulated engine failure on takeoff to the north from the eastern parallel runway, Mr Moore stated that "the instructor should immediately take control of the aeroplane and restore power to the failed engine": Moore affidavit (MA), par 34. The instructor conducting the training should never allow, Mr Moore stated, a dangerous situation to develop.
82. Mr Moore's confidence that flight instructors would control risks engendered during student training was not shared by either Mr De La Hunty or Mr Tizzard. During cross-examination on this topic, Mr De La Hunty gave the following evidence (T95.1-26):

"Q. Now, in relation to simulated emergencies or simulated engine failure you accept that I should ask, do you train pilots yourself?

A. Yes, I do.

Q. In relation to simulated emergencies of engine failure the trainee pilot is in the company of an instructor?

A. Or an authorised testing officer or a CAR 5.21 authorised train pilot.

Q. And in relation to those circumstances it is the person that is not the student that is the person who is primarily responsible for the aircraft?

A. Correct.

Q. So if the student does something wrong, reckless or potentially dangerous, the person in the other seat is required to take control of the aircraft from the student?

A. Yes.

Q. And in relation to simulated emergencies, because it is not a real emergency an engine can always be turned back on?

A. In a simulated emergency there is lots of accidents caused by misidentification of which aircraft has been simulated and failed. So it is an area of risk and it cannot be said that it can always be turned back on. If the instructors pull it back too far then it may not be recoverable.

Q. So if the instructor has also made a mistake?

A. Correct."

83. Mr Tizzard opined that flight instructors are fallible. He provided the example of an instructor being distracted by monitoring the student. He did not believe that instructors would always be vigilant and familiar with the area in which they fly. During his oral testimony, Mr Tizzard testified as follows (T27.6-26):

" HIS HONOUR

Q. What is your experience with distractions, in your years being of being an instructor?

A. Your Honour, having taught the first lot of Papuans to fly I have a lot of experience in distractions of students perhaps unwell or unsure of themselves, and that is a big distraction as a flying instructor if your trainee is having difficulty, your Honour.

O'SULLIVAN

Q. And are you able to tell his Honour of what other matters may cause a pilot to become distracted whilst in control of an aircraft?

A. Your Honour, that's enormously complicated: Position of the sun, turbulence, concerns about fuel state. The answer to that could go on infinitum.

HIS HONOUR.

Q. Would that also depend upon the experience of the pilot?

A. Yes, your Honour, that could be a factor as well."

84. According to Mr Tizzard, "the experience levels of many young flying instructors have been question[ed] recently by CASA as evidenced by its practice of increasing the frequency and rigour of its flight testing of flight instructors": ex A, par 30. He did not believe that it was prudent to assume that all flight instructors would never allow a dangerous situation to develop. When questioned on the possibility of a collision with the tower in a simulated emergency, Mr Tizzard gave the following evidence (T66.1-27):

"Q. In relation to the simulated emergency, you would accept that in the majority of cases The Oaks the carrying out of pilot training and pilot certification which involves a simulated emergency in the circuit area to which we are concerned will be able to continue without risk of incident, in the majority off cases?

A. Now, you have added majority of cases, yes, ma'am, I would agree.

Q. To the extent there is any risk, you say that risk would manifest itself only in circumstances where both the pilot and the student, or the pilot being certified, have either failed to become aware of the Telstra pole through their past experience with the airfield, failed to see it, or forgotten about it?

A. Yes.

Q. That would require both pilots simultaneously to be under those conditions?

A. Well, ma'am, the first bit of your question, yes but very complex interactions going on in the aviation classroom of the sky.

HIS HONOUR: I didn't hear the answer.

WITNESS: My comment is, in the classroom of the sky the aeroplane is moving at several hundred feet a second and all sorts of complex interaction. I agreed with the comment ordinarily. But there is the nonordinary circumstance. One might have forgotten, one might have seen it, one might have thought the other seen it, and that's why I was hesitant in giving that answer."

85. During cross-examination, Mr Moore testified that in a student instructor situation it was possible but not very likely that an occasion could be created when the reaction was not fast enough to stop a collision. From the literature he had read the reaction time to avoid a collision was between 10 or 12 seconds. He estimated that a small plane departing to the north from about the middle of the eastern runway and turning right could reach the tower in something like six or seven seconds. As the plaintiff pointed out in written submissions no margin is left for error.
86. As to pilots flying solo for the first time or shortly thereafter, Mr Moore was of the opinion that they would be able to cope with emergencies that may arise as their training would be fresh in their mind. Recent training, however, does not present a bastion against an inability to cope with an unforseen exigency during a solo flight. The truth is that a pilot's inexperience increases the risk. Unexpected turbulence or windshear, for instance, could make a precautionary search and landing particularly hazardous for an inexperienced pilot when flying below 200 feet in the vicinity of the tower, as could these weather conditions on an actual or simulated engine failure on take-off to the north.
87. I accept the evidence of Mr De La Hunty and Mr Tizzard that the presence of the tower will heighten the risk to pilots using the airfield for flight training.

Gliders

88. There was some disagreement between the experts as to the risk that the tower might create for glider operations from the airfield. Mr De La Hunty expressed the following opinion (ex C, par 33):

"...glider pilots are trained that if a glider is being towed on take-off by a tug aircraft and the tow rope breaks, the tug is to turn to the left and the glider is to turn to the right. If this were to occur on take-off to the North, the glider would turn right, directly into the airspace occupied by the Tower."

89. Although Mr Moore agreed that a glider pilot who experiences a tow cable break during take-off will turn to the right, he opined that "if the failure occurs at a low height such that the glider cannot circle to land safely, the pilot is unlikely to turn so far to the right as to prevent the runway being used to land the glider if sufficient height is available to do so": MA, par 36. He considered that the likelihood of an encounter with the tower in these circumstances was low because the glider pilot would usually elect to land on the runway if possible.
90. Mr Tizzard accepted that it was more likely that a glider would attempt to land at the airfield upon the tow rope breaking, but opined that it was certainly possible that it could collide with the tower depending on its position and altitude at the time of breakage: ex A, par 31.
91. During cross-examination, Mr Moore said that it was extremely unlikely but possible and not far-fetched for the glider in an emergency situation to be placed in the position such that it was manoeuvred towards the tower. He also said that the glider pilot would see the tower immediately if he was not already aware of it but as he had been operating from the airfield, he would be.
92. Somewhat surprisingly, it seems to me, it was Mr Moore's testimony that turbulence or wind would have little impact on the glider pilot's decision to get the glider back on the ground. I have difficulty understanding how, for example, strong westerly crosswinds would not have a significant impact on a glider on take off to the north at the airfield when the tow cable breaks or, furthermore, the glider encounters severe turbulence. Mr Moore's opinion that the tower would be seen by the glider pilot makes no allowance that the pilot dealing with the emergency might be distracted from looking out for the tower. Considerations of the glider pilot's experience might also arise.
93. I prefer and accept Mr Tizzard's opinion that whilst it was more likely that the glider pilot would attempt to land after a tow rope breakage, it was possible that the glider could collide with the tower depending on its position and altitude (to which I would add prevailing weather conditions) at the time of breakage.

The Collision Risk Model

94. Mr Moore used the Collision Risk Model (CRM) "to assess the risk of an aeroplane or helicopter colliding with the mast during IFR [Instrument Flight Rules] operations": MA, par 45. He explained that the CRM is designed to provide risk computations (separately for all obstacles and for individual obstacles) to a specific set of conditions and runway environments, and to provide minimum obstacle clearance altitude (OCA) or obstacle clearance height (OCH) values for a specific set of conditions and runway environments. The CRM is used globally, Mr Moore stated, to determine whether the precision instrument approach procedure altitudes are safe: MA, par 46.
95. The CRM assessed the risk of an aeroplane or helicopter colliding with the tower during IFR operations as 9.6 in 100 million approaches. He stated at par 51:

"At the rate of 200 movements per day (or 73,000 annual movements) claimed by Mr Onus..., this is equivalent to less than one collision every 136 years on average. This assessment is conservative in that it assumes that all movements are landings and that there are no take-offs. If take-offs are included as half of the claimed movements, the likelihood of collision during an approach to land reduces to (10,000,000 / 36 500) or approximately one collision every 274 years on average. The probability of a collision with the mast during VFR operations is less than this because of the greater manoeuvring precision associated with VFR flight. Acceptable (or trivial) risk criteria used by CASA are based on the acceptability of one chance in 10,000 each year of one fatality resulting from a particular type of aircraft accident. This is equivalent to one in 100,000 for 10 fatalities and one in a million for 100 fatalities. At 73,000 annual movements the probability of a single fatality arising from a collision with the mast during a visual approach is more than 250 times lower than the acceptable risk."

96. The information required for undertaking the modelling, Mr Moore recounted, consisted of the distance measured along the extended runway centreline from the runway threshold to the tower (137 metres), the perpendicular distance from the runway centreline to the tower (180 metres) and the height of the tower above the runway threshold (35 metres): MA, par 49.
97. Mr Tizzard criticised the use by Mr Moore of the CRM as the airfield is an ALA used by light aircraft flying under VFR rather than IFR and Mr Moore had modelled something that could not happen at the airfield. Mr Tizzard stated that the CRM may be relevant when considering "collision risks for large jet passenger aircraft carrying multi-million dollar sophisticated computerised systems linked to an airport based Instrument Landing System... at a major airport, but not for modelling the behaviour of small aircraft and gliders flown, in many cases, by student or inexperienced pilots": ex A, par 34.
98. Mr Tizzard believed that the "Swiss Cheese" accident model was more appropriate for modelling aviation risks at the airfield.
99. The plaintiff did not introduce into evidence any mathematical or statistical material to assess the risk of aircraft collision with the tower but argued that the CRM has very little to do with what happens in real life at the airfield.
100. In cross-examination, Mr Moore agreed that the CRM did not take into account the full range of aircraft movements at the airfield but said that the model was not intended for that purpose. By including the CRM, he had tried to demonstrate "the relative precision of manoeuvring an aeroplane by visual references as distinct from manoeuvring the same aeroplane without visual reference to the ground": T130.42-45. He accepted that in order to give a proper impression, the operations at the airfield such as precautionary search and landings and simulated emergencies would need to be addressed.
101. The usefulness of the CRM, it seems to me, is dependant upon the reliability of Mr Moore's conversion of the assessment of the risk of the collision during IFR operations to a risk assessment of collision during VFR flight. As the CRM modelling does not take into account the operations conducted during pilot training at the airfield (other than baulked landings) and that 80 per cent of the movements at the airfield involve student pilots, I have concluded that the CRM analysis is of little assistance in the calculation of risk in the present case.

The Ambidji report

102. The defendant did not seek to rely on the Ambidji report (the report) in these proceedings. The plaintiff submitted that the defendant did not do so because it was "obviously flawed": par 87, submissions. Various complaints were made in the affidavits of the plaintiff and Mr De La Hunty about the report and the plaintiff submitted that any development consent granted on the basis of the report was questionable.
103. In response, the defendant contended that the plaintiff's submissions failed to recognise that the Council approval was unimpeachable in these proceedings and the report was largely irrelevant. The defendant argued that it did not need to defend anything other than the claim before this court, namely whether the tower constitutes an actionable nuisance and the terms of the report and the plaintiff's concerns did not assist in the resolution of this issue.
104. In my opinion, the defendant's submissions are to be accepted. These proceedings are not a challenge to the Council's development approval, which remains valid until declared otherwise: Coalcliff Community Association Inc v Minister for Urban Affairs and Planning [1999] NSWCA 317; (1999) 106 LGERA 243. I regard the report and the plaintiff's criticisms of it to be irrelevant to my determination of whether the plaintiff's claim in nuisance has been established. I should add that the approval of the development application does not mean that the plaintiff is prohibited from establishing a public or private nuisance. The Council's approval is not a defence in these proceedings: Hunter & Ors v Canary Wharf Ltd [1997] 1 AC 655.
105. It is convenient to mention here that CASA's advice that the tower does not penetrate within the "obstacle free area" as defined in CAAP 92-1(1) is a matter to which some weight is to be given but it does not follow that the plaintiff is disentitled from the quia timet relief that he seeks. Also worthy of mention is the RA-Aus guideline for the safe conduct of a take-off which sensibly provides at par 11.7:

"...it is also prudent to avoid taking off in a direction that takes you close to structures, trees, masts, and powerlines unless you are sure that the aircraft will clear them by whatever safety margin you consider acceptable within the existing atmospheric conditions."

Assessment of risk - a conclusion

106. I am satisfied on the balance of probabilities that the potential risk to aviation safety that a 35 metre high tower will create, is not confined to the scenarios referred to in pars 12 and 13 of the defendant's closing submissions. The risk may arise during emergencies, precautionary search and landings, baulked landings, glider operations and unfavourable weather conditions as has been canvassed earlier on in this judgment.
107. The degree of the probability of the occurrence of the risk will vary in each of the discussed operations. Although the probability of a tower collision occurring will be low in the case of an experienced pilot or instructor, the degree of the probability of the risk increases when the experience of the pilot or instructor is limited. The dominant use of the airfield is for pilot training and the likelihood of the risk is heightened in the case of student pilots flying solo or recently licensed pilots. The level of the risk arising during an emergency will be dependent upon its nature and the experience of the pilot.
108. I do not accept the defendant's argument that any risk is so remote to be no real risk at all. I am satisfied on the balance of probabilities that the risk is not one which is far-fetched or fanciful. There is a reasonably foreseeable risk that aircraft will collide with the tower and that death, or at the very least serious injury, will be occasioned to the occupants of the aircraft.

Public Nuisance

Legal principle

109. The elements of the tort of public nuisance include common injury to a section of the public: R v Rimmington [2005] UKHL 63; [2006] 1 AC 459 at 484. In Attorney-General v PYA Quarries Ltd [1958] EWCA Civ 1; [1957] 2 QB 169 Denning LJ observed at 190-191:

"The classic statement of the difference is that a public nuisance affects her Majesty's subjects generally, whereas a private nuisance only affects particular individuals. But this does not help much. The question, "When do a number of individuals become Her Majesty's subjects generally?" is as difficult to answer as the question, "When does a group of people become a crowd?" Everyone has his own views. Even the answer "Two's company, three's a crowd" will not command the assent of those present unless they first agree on "which two". So here I decline to answer the question how many people are necessary to make up Her Majesty's subjects generally. I prefer to look to the reason of the thing and to say that a public nuisance is so widespread in its range or so indiscriminate in its effect that it would not be reasonable to expect one person to take proceedings on his own responsibility to put a stop to it, but that it should be taken on the responsibility of the community at large."

110. Another element of a public nuisance is that the defendant must have knowledge, or ought to have known (because the means of knowledge were available to the defendant) of the nuisance to the public: R v Goldstein [2005] UKHL 63; [2006] 1 AC 459 at 485. Further elements of the tort are:
     • The defendant has the means to abate the nuisance; and
     • The defendant fails to take appropriate steps to abate it.
       
111. There are three ways that an action for public nuisance at common law may be commenced:
     1. On the Attorney-General's own motion;
     2. By an individual in a relator action where the fiat of the Attorney General has been obtained; and
     3. By a private action for public nuisance where the individual can demonstrate that he has suffered substantial particular damage beyond that suffered in common by all other members of the public affected by the nuisance.
112. In the present proceedings, the plaintiff brings his claim for injunctive relief without obtaining the Attorney General's fiat. It is necessary for him to establish that he has standing to bring such an action. In McFadzean v Construction, Forestry, Mining and Energy Union [2007] VSCA 289; (2007) 20 VR 250; Warren CJ, Nettle and Redlich JJA, when discussing the question of standing in respect of public nuisance, said at 284:

"An injury for public nuisance is not actionable unless it be the "direct, necessary, natural and immediate consequence of the wrongful act". Consequently, as Lord Hanworth MR and Lawrence LJ both held in Harper v GN Haden & Sons Ltd [1933] CH D 298, a private individual cannot maintain an action in respect of wrongful obstruction of the highway unless the individual has suffered particular substantial injury beyond that suffered in common by all other members of the public affected by the nuisance. A claimant may establish "particular" damage where he or she has suffered injury or inconvenience which is a direct and not merely consequential result of the public nuisance and is of a substantial character so as to distinguish it from the inconvenience suffered by the public at large."

113. A complicating feature in discussing the legal principles applicable to the tort of public nuisance is that in Brodie v Singleton Shire Council, Ghantous v Hawkesbury City Council [2001] HCA 29; (2001) 206 CLR 512 the feature of the tort was raised in obiter dicta by Gaudron, McHugh and Gummow JJ. Their Honours said at 570:

"The time has now come, by parity with the reasoning in Burnie Port Authority v General Jones Pty Ltd [1994] HCA 13; (1994) 179 CLR 520 at 556 to treat public nuisance, in its application to the highway cases, as absorbed by the principles of ordinary negligence. In any event, as has been indicated above, the intrusion of nuisance into this field in the mid-nineteenth century lacked any firm doctrinal basis".

114. These remarks were adopted by Gleeson CJ and Hayne J in Leichhardt Municipal Council v Montgomery [2007] HCA 6; (2007) 230 CLR 22. It is, however, unclear whether the absorption of public nuisance into the law of negligence will extend beyond the liability of highway authorities. As the present claim for injunctive relief does not involve a highway authority, I propose to determine the plaintiff's claim in accordance with the long established principles of the tort of public nuisance.
115. I should mention the onus of proof. The plaintiff bears the onus of establishing a public nuisance on the balance of probabilities. Once the nuisance is proved and the defendant is shown to have caused it, then the onus shifts to the defendant to justify or excuse itself: Southport Corporation v Esso Petroleum Co Ltd [1954] EWCA Civ 5; [1954] 2 QB 182; Hiscox Syndicates Ltd v The Pinnacle Ltd [2008] EWHC 145 (Ch).

Argument

116. The plaintiff argued that the tower will constitute a public nuisance in that it will create a danger to aviation safety. Aircraft flying at low altitude within the tower's vicinity will be unsafe in the circumstances identified by Mr De La Hunty and Mr Tizzard. The defendant submitted that the plaintiff had neither proven an interference with the public nor that he suffers particularly as a consequence of that interference. Rather, the evidence established that the public at large (the neighbourhood) was not affected by the tower nor was general aviation. The defendant argued that the evidence, therefore, failed to identify an impact on a group of persons sufficient to constitute the public as is required to compromise a public nuisance. Even if the plaintiff was able to demonstrate a nuisance to the public, the defendant put to me that a particular damage such that the plaintiff would have standing to bring the proceedings had not been demonstrated. There was no evidence of direct interference with the use of land nor was there evidence that people will choose to fly and land elsewhere if the tower is installed. This was submitted to be "generally the least" that would be expected to establish standing.
117. The plaintiff's suggestion that he will have to close a runway and therefore lose money, the defendant contended, was a cost not arising as a consequence of the tower but of the plaintiff's fears that are unsupported by the evidence. This response was unreasonable and could not be attributed to the tower.
118. During oral submissions, Ms Duggan drew an analogy to an open roadway where the majority of the public can continue to drive along the roadway and "some distance from the roadway, is a structure which only some people may come into conflict with if they operate outside the ordinary norms of driving": T194.23. No one would suggest that such a structure, Ms Duggan said, would comprise a nuisance. She put to me that the present case is the same because to the ordinary flow of traffic in and out of the airfield, the tower will pose no constraint whatsoever.
119. Ms Duggan further submitted that the question of safety would not have an impact in relation to a public nuisance but such a question becomes relevant, if it be found that the interference is capable at law of comprising a nuisance, in then deciding whether it is an unreasonable interference with the rights of the public.
120. Ms Duggan did not cite any authority in support of that proposition and I do not think it is correct. After all, a public nuisance is an unlawful act or omission, which endangers the life, safety, health, property or comfort of the public: In re Corby Group Litigation [2008] EWCA Crim 2177; [2009] QB 335. I do think that whether the act or omission endangers the lives, safety or health of the public is a factor which can be taken into account in assessing whether the act or omission is a public nuisance.
121. On the issue of reasonableness, Ms Duggan submitted that any interference was not unreasonable. She pointed out that if the plaintiff's land use is more sensitive to interference than the normal user, the plaintiff is not entitled to relief, the rationale being that if the plaintiff's use requires some extraordinary protection he should have bargained for it. Ms Duggan cited what was said in Robinson v Kilvert 41 ChD 88 by Cotton LJ at 94:

"But no case has been cited where the doing something not in itself noxious has been held a nuisance, unless it interferes with the ordinary enjoyment of life, or the ordinary use of property for the purposes of residence or business. It would, in my opinion, be wrong to say that the doing something not in itself noxious is a nuisance because it does harm to some particular trade in the adjoining property, although it would not prejudicially affect any ordinary trade carried on there, and does not interfere with the ordinary enjoyment of life".

122. Ms Duggan argued that as the interference which is asserted in large part only arises because of a particularly sensitive use of the plaintiff's land as a training airport and the peculiar areas of that use which the plaintiff says will be affected, the court would not find that the nuisance is unreasonable.

Decision

123. The evidence does not demonstrate that the tower will interfere with 'normal operations' in and out of the airfield. By 'normal operations' I mean when nothing material goes wrong. As has been previously observed, the degree of the probability of the occurrence of the risk that the presence of the tower will have upon the safety of aviators will depend upon variables such as the nature of the flight operation, level of emergency, meteorological conditions and pilot experience. I note that any aircraft that uses the airfield may experience an emergency.
124. Even if the occurrence of a collision between an aircraft and tower takes place rarely, this does not mean that the tower's presence does not amount to a public nuisance. The certainty is that if an aircraft collides with the tower, the consequences will be horrendous. As Denning LJ said in PYA Quarries at 192:

"But an isolated act may amount to a public nuisance if it is done under such circumstances that the public right to condemn it should be vindicated".

125. Whilst I do not doubt that flying is a potentially dangerous activity, the construction of a 35 metre high tower at a distance of 147.59 metres from the edge of the eastern runway of an airfield that is predominately used for pilot training will, I am satisfied on the balance of probabilities, materially add to the risk to the safety of occupants of aircraft which use the airfield. The increased risk is neither trivial nor fleeting.
126. I am satisfied on the balance of probabilities that the potential threat to aircraft safety by the erection of the tower constitutes a nuisance "so widespread in its range" and "so indiscriminate in its effect" ( PYA Quarries per Denning LJ at 191) upon aviators and their passengers who use the airfield that it is a public nuisance.
127. As to the element of knowledge of the nuisance to the public, it is clear that the defendant was aware that considerations of safety may arise and commissioned the Ambidji report, whose authors considered that the tower did not present a hazard to the safety of aircraft. Having had the advantage of the evidence in this case, I have concluded otherwise.
128. There is evidence, in my view, of facts, matters and circumstances from which the defendant ought to have known of the nuisance and the defendant has constructive knowledge of it: Rickard v Allianz Australia Ltd [2009] NSWSC 1115.
129. The question remains whether the plaintiff has standing. It seems to me that the tower has a direct and adverse impact upon his enjoyment of his land due to the increased risk to the safety of occupants of aircraft operating into and out of the airfield to whom he owes a duty of care. The steps that the plaintiff said that he would take if the tower was erected (see [24] above) were not challenged by the defendant in cross-examination. The defendant's criticism was founded upon the plaintiff's understanding that all aircraft using the airfield would be at serious risk of colliding with the tower.
130. In the event of the tower being constructed to the height of 35 metres the plaintiff will be immediately confronted with the reasonably foreseeable risk to the safety of the occupants of aircraft using his airfield. I consider, on the evidence, the steps he proposes to take to lessen the danger arising from the public nuisance to be reasonable. The runway closures and prohibitions and advices against flying that the plaintiff envisages, will, I accept, diminish the airfield's utility for pilot training and reduce the revenue from landing fees. The defendant's criticism that there was no evidence that aircraft would go elsewhere lacks substance. All of these measures reflect the seriousness of the direct impact that the tower will have upon the plaintiff's enjoyment of his land. I am satisfied on the balance of probabilities that he will suffer particular substantial injury beyond that suffered in common by those who fly in and out of the airfield. I find that he has standing to seek injunctive relief to restrain the public nuisance.
131. I am satisfied on the balance of probabilities that the plaintiff has proven a public nuisance.
132. I turn to the issue of reasonableness. In Elston v Dore [1982] HCA 71; (1982) 149 CLR 480; Gibbs CJ, Wilson and Brennan JJ were of the opinion at 488 that the "proper test to apply in most cases" concerning what would be considered a reasonable use of land was the statement in Sedleigh-Denfield v O'Callaghan [1940] UKHL 2; [1940] AC 880 by Lord Wright at 903:

"It is impossible to give any precise or universal formula, but it may broadly be said that a useful test is perhaps what is reasonable according to the ordinary usages of mankind living in society, or more correctly in a particular society."

133. It appears that the plaintiff is not required to prove that the public nuisance is unreasonable but reasonableness of the defendant's use of the land is a defence to the plaintiff's claim. In Hiscox Syndicates , Hodge AJ said at [30]:

"The reasonableness and propriety of the contractors' operations operates by way of a defence to a claim in the tort of nuisance rather than the absence of it being a necessary ingredient of the adjoining landowners' cause of action. In my judgment, a cause of action is constituted by causing undue inconvenience or discomfort to one's neighbour. The evidential burden of proof, once that has been demonstrated, then shifts to the alleged tortfeasor adduce evidence to show that all reasonable and proper steps were taken to ensure that such nuisance would not occur."

134. What is known of the defendant's intended use of the land is confined to the Statement of Environmental Effects prepared by NGH Environmental. The tower is intended to provide improved mobile phone coverage to the local area on the defendant's Next G network. There is no evidence as to why the proposed height of the tower is thought to be necessary. I take into account that the defendant's use of the land has been lawfully obtained and has a legitimate commercial purpose. Another factor I weigh in the defendant's favour is the approval of the development application by the Council. It does, however, seem that there were three other options at the Oaks, namely the Dudley Chesham Sports Ground site in McIntosh Street, the Glendiver Road site and the cemetery site that were identified for the location of the tower. No issues of public safety or lack of adequate mobile coverage are identified in the summary of each of the candidate sites at par 3.2 of the NGH report. The present site was selected in the report for the reasons recorded at [17] above, namely "low environmental impact", the likelihood of causing "the least community concern", satisfaction of "Rural Fire Brigade requirements" and provision of "the necessary coverage for the target area". The evidence does not disclose what the requirements of the Rural Fire Brigade are nor does it suggest that they could not be met by the erection of the tower upon any other of the alternative sites.
135. On the evidence before me, the defendant's case for the location of the tower of the proposed height in close proximity of the airfield is hardly compelling. The issue of reasonableness requires a balancing exercise to be undertaken between the defendant's commercial interests in erecting the tower in accordance with the Council's development approval and the public interest in the safety of the occupants of aircraft which use the airfield.
136. I should mention that the present case is very different to the circumstances upon which Robinson v Kilvert was decided. In that case, the court was not concerned with issues of public safety or the gravity of the consequences that might arise because of the nuisance. Moreover, the predominant use of the airfield has been for many years pilot training and the strong probability is that the proposed construction of the tower will have a substantial prejudicial impact upon the ordinary enjoyment of the airfield by the plaintiff. The balancing exercise leads me firmly to the conclusion that the public interest in aviation safety must prevail.
137. I am further of the opinion that the defendant has not shown that all reasonable and proper steps were taken to ensure that the public nuisance would not occur. The plaintiff is entitled to injunctive relief.
138. Before cogitating upon how the discretion is to be exercised, I will go on to consider the plaintiff's assertion of a private nuisance. In view of the finding of a public nuisance, the discussion will be more succinct than it would otherwise have been.

Private nuisance

139. The plaintiff founds his assertion of a private nuisance on the steps that he will be required to take which are recorded at [24] above. In the plaintiff's outline of submissions, he particularly referred to the need to close the eastern runway and to prohibit certain types of flying in certain conditions and to the duty of care that he owed to persons using the airfield.
140. The defendant submitted that the plaintiff does not allege that the tower will interfere with the use of his land. Rather the defendant asserts that the tower will interfere with the activities of people who use the land once they have left it (and the airspace connected with that land) or when approaching the land (and its airspace). This argument was developed so as to identify the plaintiff's complaint to be "about the incapacity to use the land of another, being its airspace" and to the inconvenience of another to get to his land. The defendant put to me that except in special cases, nuisance will only arise in cases of an asserted undue interference where there is some emanation from the defendant's land to the plaintiffs. Reliance was placed by what was said by Lord Goff in Hunter v Canary Wharf at 686:

"At all events the mere fact that a building on the defendant's land gets in the way and so prevents something from reaching the plaintiff's land is generally speaking not enough for this purpose."

141. The plaintiff placed reliance upon decisions of Canadian and American authorities whereby structures on private lands nearby aerodromes were found to be both public and private nuisances. The cases cited were Manitoba (Attorney General) v Campbell (1983) 26 CCLT 168; United Airports Co of California v Hinman (1940) US Av R 1; Oakley v Simmons 799 SW 2d 669, (Tenn.Ct.App., 1990) and Commonwealth ex rel v VonBestecki , 30 Pa. D. & C. 137 (Pa.Com.Pl., 1937).
142. The courts in those cases did not feel constrained by the lack of emanation from the defendant's land to the plaintiffs. In United Airports , McCormick J, presiding in the United States District Court, Southern District of California, in granting an injunction to an owner of a private airport restraining the erection of structures more than 10 feet high upon the land of an adjoining land owner at or near the boundary of the airport said at 6:

"So that landing facilities at said airport be free from danger, it is imperative that no obstructions be placed in or about the approaches to said airport that will interfere with or prevent airplanes from approaching said airport and landing thereat in the manner aforesaid."

143. I do not propose to further detail these cases other than to state that none of the structures that were found to be a nuisance had a legitimate commercial purpose, which the defendant's tower has and, unlike the present case, the various menaces to air safety were improperly motivated.
144. In Hargrave v Goldman [1963] HCA 56; (1963) 110 CLR 40, Windeyer J defined at 59 the tort of private nuisance to be an unlawful interference with the occupier's use or enjoyment of land, or of some right over, or in connection with it. His Honour said at 62:

"In nuisance liability is founded upon a state of affairs, created, adopted or continued by one person (otherwise than in the reasonable and convenient use by him of his own land) which, to a substantial degree, harms another person (an owner or occupier of land) in his enjoyment of the land."

145. In Melaleuca Estate Pty Ltd v Port Stephens Council [2006] NSWCA 31, Giles JA (with whom McColl JA and Hunt AJA agreed) said at [22]:

"For the legal wrong of (private) nuisance, a nuisance is an unreasonable interference with the use and enjoyment of land: an "invasion of the common law rights of an owner or occupier of land" ( Hargrave v Goldman [1963] HCA 56; (1963) 110 CLR 40 at 60 per Windeyer J). Preferably used, the word denotes the result of the defendant's conduct, or perhaps the state of affairs created by the conduct and bringing about the result. Thus in Torette House Pty Ltd v Berkman [1940] HCA 1; (1940) 62 CLR 637, in which water discharged from the defendant's premises onto the plaintiff's premises, DixonJ said (at 657) that there was "no nuisance or other wrongful act on the part of anyone of which the plaintiff could complain until the water began actually to flow onto the plaintiff's premises". Also preferably used, finding a nuisance does not mean legal liability for the result of the defendant's conduct. In some circumstances there may be an unreasonable interference with the use and enjoyment of the plaintiff's land without liability in the defendant."

146. The plaintiff must prove on the balance of probabilities that there has been a substantial and unreasonable interference in the enjoyment of his property by the defendant. He is not obliged to show that the tower is an unreasonable use of the site by the defendant nor must the defendant prove that the use of the site is reasonable.
147. Some fault on the defendant's part must be established: Sutherland Shire Council v Becker [2006] NSWCA 344; Robson v Leischke [2008] NSWLEC 152; (2008) 72 NSWLR 98. The relevant fault in this case is foreseeability.
148. It is rarely the case that the use of land by a defendant which does not cause something to emanate from it, although its use interferes in some way with the use and enjoyment of the plaintiff's land, will amount to a private nuisance: Hunter v Canary Wharf at 685-686, Robson v Leischke at 118. There have been cases, however, where a private nuisance has been established although there was no material physical interference with the plaintiff's land or their use of it. For example in Thompson-Schwab v Costaki [1956] 1 All ER 652; [1956] 1 WLR 335 which concerned prostitutes operating in the street, Lord Evershed MR said at 339:

"The perambulations of the prostitutes and of their customers is something which is obvious, which is blatant, and which, as I think, the first plaintiff has shown prima facie to constitute not a mere hurt of his sensibilities as a fastidious man, but so as to constitute a sensible interference with the comfortable and convenient enjoyment of his residence."

149. The facts of the present case are markedly different to those that have given rise to unsuccessful actions of private nuisance such as the erection of structures that spoil a view or restrict the flow of air or take away light or interfere with the enjoyment of television signals. The tower presents a danger to the safety of aircraft operating into and out of the airfield. I do not agree with the defendant's submission that the plaintiff's case must be unsuccessful because there is no emanation from its site. I think that this is a special case where the 'mere' presence of the tower of the intended height at a close proximity to the airfield constitutes an actionable nuisance.
150. There is a reasonably foreseeable risk that aircraft will collide with the tower causing death, or at the very least serious injury, to the aircrafts' occupants. The tower will materially add to the risk to the safety of pilots and passengers of aircraft that use the airfield. The plaintiff's long-standing enjoyment of his land has been as an airfield that is predominantly used for training. All of the steps that the plaintiff proposes to take are a reasonable response to the heightened risk to aviation safety. The airfield's utility for pilot training will be diminished and revenue from landing fees reduced. I am satisfied on the balance of probabilities that the plaintiff's enjoyment of his land will be harmed to a substantial degree. I cannot agree with the defendant's argument that the plaintiff's complaint is confined to the users of airspace and to their inconvenience in travelling to his land. I am further satisfied on the balance of probabilities that the substantial interference to the plaintiff's enjoyment of his land is reasonably foreseeable by the defendant.
151. Turning then to the question whether the substantial interference is unreasonable, a balance is to be maintained between the right of the defendant to erect the tower to its intended height on the site and the plaintiff's right not to be interfered with: Sedleigh-Denfield at 903. In undertaking the balancing exercise I give weight to the commercial interests of the defendant and the development approval.
152. On the other hand, the proposed construction poses a substantial threat to the utility of the plaintiff's land. The threat is not transitory and concerns the safety of the occupants of aircraft that use the airfield. There are alternative sites for the tower that do not share such a close proximity to the airfield.
153. I am satisfied on the balance of probabilities that the tower of the proposed height in such a close proximity to the airfield unduly interferes with the plaintiff's enjoyment of his land. I find that the substantial interference is unreasonable.
154. The plaintiff has established, in my opinion, a private nuisance for which he is entitled to injunctive relief.

Form of orders sought

155. Ms Duggan submitted that if the plaintiff was entitled to relief the court should not make the order in the form sought in the summons. The evidence, it was said, does not support the defendant being restrained from erecting any structure above 5 metres and the order sought goes beyond that reasonably required to protect any perceived infringement of the plaintiff's use of his land. It was further contended that the evidence was not that any structure above 5 metres was of concern. Rather the only occasion where the structure could affect flights "is somewhere yet undefined between 115 feet (35 metres) and 50 feet (15.24 metres)". The defendant put to me that there was no evidence to support an injunction to restrain a structure below a reasonably necessary height.
156. It appears that Ms Duggan's point as to the height between which flights might be affected by the tower is based on Mr Tizzard's evidence that after the first two flyovers by an aircraft in the course of a precautionary search and landing, the third flyover would be conducted at a height between 50 feet and 200 feet: T52.29-30.
157. Mr McCarthy responded by pointing out that there was no evidence that the defendant intended to do anything other than to erect a 35 metre high tower but the plaintiff would not contest or have an argument with an order that the tower was to be the height of the trees in the surrounding area, Mr McCarthy said those trees were 12 metres high.
158. A difficulty with that concession is that the trees on the airfield boundary range in height between 16 metres and 18 metres. Other than the trees, on the eastern side of the North-South runway are tennis courts with night lights around 12 to 13 metres in height and a football ground with light poles about 16 metres high. There is no evidence as to the precise distance any of these objects are from the eastern edge of the North-South runway but it appears from the photograph being ex B, annex GO-3 that the tennis court lights and trees are closer than the tower. At a height of 35 metres, the tower is twice the height of any of the nearby structures and almost twice the height of the tallest trees.
159. Another structure merits mention. Optus has erected a 20 metre high mast to the south of the Oaks township for its mobile network. The mast is to the east of the East-West runway. Although there is no evidence as to how far it is from the easterly end of that runway, it is apparent from the Google image in ex 4 that the mast is at a distance considerably further from that runway end than the tower is from the easterly edge of the North-South runway.
160. The aim of a quia timet injunction is to do justice between the parties having regard to all the relevant circumstances: Hooper v Rogers [1975] 1 Ch 43 per Russell LJ at 50. It seems to me that as the trees are closer to the eastern edge of the North-South runway than the tower and the tallest of those trees is 18 metres high, the probability that the risk to the safety of aircraft being increased by the construction nearby of a tower of a height not in excess of 18 metres is not substantial. A tower, not in excess of that height, is neither a public nor a private nuisance.
161. I do think that justice between the parties having regard to all relevant circumstances is achieved by restricting the maximum height of the tower to 18 metres.

ORDER

162. For the foregoing reasons, I make the following order:

The defendant, whether by itself, its servant or agent, is restrained from erecting any structure over a height of 18 metres at the property at 33 McIntosh Street, The Oaks, in the State of New South Wales, 2570 being the land comprised in folio identifier 21/730754.

I will hear the parties on the question of costs.

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