Precautionary search and landing
49There 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.
50Mr 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.
51In 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.
52The 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.
53Although 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."
54Mr 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.
55In 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.
56As 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.
57It 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."
58Mr 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.
59Although 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.
60Mr 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)
61It 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.
62During 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.
63As 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.
64Mr 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. "
65I 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.
66On 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.
67Furthermore, 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.