Collision with terrain

The pilot was conducting a flight to satisfy distance, height and duration requirements for the silver endorsement on his gliding certificate. One of the requirements was that the flight should last for at least five hours. After about three hours flying the pilot felt slightly nauseous, and about an hour later he became extremely nauseous and vomitted. His condition then improved, and he elected to continue the flight. He subsequently arrived in the circuit area at an indicated altitude of 2500 feet, and intended over- flying the field before joining a left circuit to land. He was aware that the angle was unusual but deferred to his altimeter, assuming his perception had changed as he had been above 5000 feet for most of the flight. He then realised that the aircraft was much lower than the indicated height and that a landing on the intended strip would not be possible. While manoeuvring to land on another strip, the left wing tip touched the ground and the aircraft swung through about 120 degrees before striking the ground heavily. After the accident the pilot discovered that he had inadvertently set 1000 feet instead of zero on his altimeter before DEPARTURE. The pilot was aware of the problems of sun exposure and had taken suitable precautions. These precautions were apparently insufficient to counter the effects of dehydration and heat stress.

The pilot hired the aircraft privately from his employer to conduct a holiday flight during his leave. The journey commenced at Moorabbin on 25 August and the aircraft arrived at Cairns about midday 30 August, after stopovers at Coolangatta and Proserpine. The pilot and his passengers then spent the next three days at leisure in the Cairns area. On the day of the accident, the pilot attended the Cairns Briefing Office where he collected the relevant weather forecasts and submitted a flight plan. The flight plan indicated that the flight would be conducted in accordance with Instrument Flight Rules. It contained a deficiency in that no details were given for the first route segment from Cairns to Biboohra. It is apparent that the pilot had not noticed that the tracks to the west of Cairns, on the relevant enroute chart, emanate from Biboohra and not Cairns. There was no track line which joined Cairns and Biboohra. Such a line might have alerted the pilot at the time he planned the flight. The error in the flight plan was not detected when the plan was submitted. When the pilot was issued with an airways clearance prior to DEPARTURE it was apparent that he did not understand the terms of the clearance, which gave the initial tracking point as Biboohra. The location of this point was explained to the pilot and he subsequently accepted the clearance. He elected to depart using visual procedures, after being offered a choice of these or the published Standard Instrument DEPARTURE profile. A visual DEPARTURE from the particular runway in use allows an aircraft proceeding towards Biboorha to intercept the required track sooner than is possible with an instrument DEPARTURE. The aircraft was issued with takeoff instructions which included clearance for the pilot to make a right turn after takeoff. Witnesses observed that the aircraft complied with this clearance and headed in a south-westerly direction before turning to the north-west and subsequently entering cloud. The cloud base was estimated to be between 2000 and 2500 feet above mean sea level. No further communications were received from the aircraft and a search was commenced that afternoon. The search effort was hampered by the weather and the wreckage was not located until the following afternoon. Inspection of the wreckage indicated that the aircraft struck the the top of a ridge line, 250 metres south-west of the highest point of the Mt Williams area. At the time, the aircraft was on a west-north-westerly heading, flying wings level and climbing at a angle of about five degrees. No fault was found with the aircraft that could have contributed to the occurrence. At the time the aircraft entered cloud, the pilot should have reverted to Instrument Flight Rules procedures. To comply with these procedures a pilot is required, inter alia, to ensure that adequate terrain clearance is achieved during climb to the lowest safe altitude. The relevant altitude for the route segment Cairns to Biboohra is 4500 feet above mean sea level (amsl). As the aircraft was apparently under control at the time of impact with the ground at about 3250 feet amsl, it was likely that the pilot had overlooked the lowest safe altitude requirements.

The pilot and passengers were overseas visitors taking part in an aerial safari. The flight apparently proceeded normally until a series of garbled radio transmissions were recorded from the aircraft, which then failed to reply to further calls. Despite an intensive search, the wreckage of the aircraft was not found for 2 months. It was evident that the aircraft had collided with trees at high speed while in a steep descending attitude. Examination of the wreckage did not reveal any pre-impact fault that could have contributed to the accident. A post analysis of the prevailing weather conditions indicated that areas of rain showers and low cloud existed over the higher terrain in the region. It is probable that the pilot lost control of the aircraft after inadvertently entering cloud.

Circumstances:

The pilot had been spraying rice fields when the aircraft began to vibrate severely and lose height. He began a turn into wind to position the aircraft for a forced landing in a dry paddock, adjacent to the field under treatment. During the turn the aircraft struck a small earth bank which tore off the main landing gear. The reason for the vibration has not yet been established. However, a piston failure is suspected as pieces of piston and piston ring material were found in the engine sump.

Circumstances:

The pilot had engaged in gliding activities for more than thirty years. These activities were interrupted in December 1987 when he underwent coronary by-pass surgery. On receipt of a medical clearance from his coronary specialist, the pilot resumed flying gliders in February 1989. He had since accumulated 31 flights of which 18 were solo. On the day of the accident, the pilot arrived at the airstrip at about 0930 hours and during the day assisted with glider launch and recovery operations. Late in the afternoon the pilot was authorised by the duty officer for a solo flight. After a winch launch in a northerly direction in light wind conditions, the glider was observed to perform several steep turns before positioning for a right hand downwind leg for a landing in a northerly direction. The pilot reported his position by radio on the downwind leg in accordance with the gliding club's standard procedures. The flight was witnessed by numerous club members who were generally located at the southern end of the airstrip. They reported the approach appeared normal until the glider was established on base leg. The turn onto the final approach was delayed such that the glider lined up on the western side of the strip which is reserved for winch launches. Soon after, when the glider was at an altitude of about 150 feet above ground level, it commenced a turn to the left. The glider levelled out on a south-westerly heading and then entered a climb, from which it apparently stalled, and dived from view behind trees. The wreckage was found in timbered country about one kilometre from the southern end of the gliding strip. The wreckage distribution suggested the glider had rolled inverted and dived near vertically into the ground. A technical examination revealed no evidence of any pre-existing fault or defect. The manoeuvres following the turn onto final approach were consistent with the pilot being incapacitated. The autopsy revealed the pilot had suffered a heart attack.

Significant Factors:

The following factors were considered relevant to the development of the accident:

1. The pilot was incapacitated when he suffered a heart attack.

2. Loss of control in flight due to pilot incapacitation.

Following a 30 minute flight the pilot landed the balloon and the passengers waited in the basket for the retrieve vehicles to arrive to effect a passenger changeover. During this period a strong wind blew up, caught the balloon and dragged it towards trees. The pilot advised the passengers to adopt a crouch position and operated the burner to apply heat to raise the balloon. The balloon climbed steeply, cleared the trees then descended rapidly, bounced and the basket began oscillating about 30 degrees either side of vertical. The pilot was thrown out of the basket and 10 of the 11 passengers received injuries, although all remained in the basket. The balloon continued to be blown along the ground and one of the passengers climbed into the pilot's section of the basket and applied heat, this took the balloon aloft. The pilot chased the balloon and after one of the retrieve vehicles located him he was able to contact the balloon by radio and relay instructions on the use of the burner to the passenger. The balloon landed about 3.5 km from the position it had been waiting to changeover the passengers.

The owner of the aircraft is reported to have worn a neck brace to assist with his recovery from a neck injury suffered some years ago. On the evening preceding the accident he had complained of feeling unwell. The next morning he rose at about 0600 hours and apparently prepared the aircraft for a flight to a neighbour's property. The wreckage of the aircraft was located about four kilometres north of the pilot's homestead at 0830 hours. The aircraft was found to have impacted the ground in an inverted attitude. Examination of the wreckage indicated that the aircraft had been constructed and maintained to a high standard and no defect could be found that may have contributed to the occurrence. The aircraft was fitted with a serviceable emergency parachute which had not been activated by the pilot. The actuating lever was readily accessible within the cockpit. Post mortem examination revealed that the pilot suffered from coronary artery disease. It was also reported that he had previously suffered several periods of total incapacitation. It is considered possible that he may suffered incapacitation in flight.

The pilot was called out at about 0400 hours local time for an urgent medical flight from Wynyard to Melbourne. This required positioning the aircraft from its base at Devonport to Wynyard. The take-off from Devonport was made in darkness with an overcast sky and light drizzle. The aircraft then apparently continued on the take-off heading at high power and low level until it struck the ground at high speed in a forest area 25 km south of Wynyard and 56 km from Devonport. The cause of the accident could not be determined but the possibility of pilot incapacitation could not be discounted.

The aircraft had been chartered to transport a television film crew to Sydney, departing Armidale at 2130 hours. After rising about 0800 hours the pilot had spent the day working in his garden and watching television. At about 1600 hours he went to the airport to prepare the aircraft for the flight to Sydney and to submit a flight plan. He returned home at 1745 hours for a meal and planned to proceed to the airport at 2045 hours. Shortly afterwards he received a telephone call from another client requesting a charter flight to Sydney. He agreed to carry out the additional flight and DEPARTURE was made from Armidale at 1830 hours, with the return flight arriving from Sydney at 2130 hours. After landing the pilot refuelled the aircraft and waited at the airport for the film crew, who were delayed and finally arrived at about 2310 hours. The film crew requested that an additional passenger be flown to Sydney and after calculating the weight of the baggage the pilot agreed to the carriage of that passenger. The aircraft was loaded, with the front seat beside the pilot being occupied by Mr Phillips. The other three passengers were seated in the rear passenger area, one facing aft while the other two faced forward. All passengers fastened their seat belts, although Mr Phillips used only the lap portion of the lap/sash belt which was provided for the front seat passenger. After both engines were started, the aircraft was taxiied to the threshold of runway 23 where the engine checks were completed. The take-off run was commenced and a witness reported that the aircraft became airborne after a ground roll of about 1100 metres and then commenced a shallow climb.It then disappeared from sight. It was established the aircraft entered a descent and shortly afterwards it collided with a number trees in an apple orchard before impacting the ground about 1400 metres beyond the point where it became airborne. Subsequent investigation did not find any fault with the aircraft or its systems that would have contributed to the accident. At the time of the accident the wind was calm, the night was dark with no moon light. Once the aircraft passed the end of the runway no ground lights would have been visible to the pilot. These conditions may cause a pilot to experience sensory illusions; so he must rely solely on the flight instruments in order to establish and maintain correct aircraft attitude. Whether the pilot of VH-AWT was affected by such illusions on the particular occasion could not be positively determined. The pilot selected the initial climb attitude of the aircraft by referring to the runway lights. This technique is considered less than optimum, for the recommended technique requires reference to the flight instruments for attitude selection and maintenance. Reliance upon reference to runway lights during the initial climb may result in a lower than desired climb attitude where a runway slopes down in the direction of take-off. This condition exists on runway 23 at Armidale. ((1))

A group of pilots had travelled from a property strip to a nearby dam in order to complete training exercises on a float-equipped Bell 47 helicopter. VH-SRE was not fitted with floats but had been used to ferry some of the pilots to the area. At the conclusion of the training operation the pilot arranged to ferry VH-SRE back to the property strip. After take-off a practice autorotation was conducted over the dam and was followed by some unauthorised low flying in the vicinity. On arrival at the strip low level runs were performed along the strip with torque turns at each end. Control of the aircraft was lost during the third of these turns and the aircraft struck the ground in a steep nose-down attitude. Fire broke out on impact and engulfed the wreckage. The subsequent investigation did not reveal any evidence of a pre-impact defect or malfunction of the aircraft which might have contributed to the accident. Several of the pilots who observed the flight reported that the final manoeuvres performed were outside the normal operating parameters of the helicopter, and were conducted at an unsafe height above the ground. It was, however, not possible to establish which of the pilots was flying the aircraft at the time of the accident.