Loss of control

On 5 June 1992, the pilot received a one hour checkout in the aircraft from an instructor. On 12 June the pilot flew the aircraft from Coldstream to Lilydale, where his passengers were waiting. While the pilot was checking the weather forecasts an instructor commented that they indicated that the weather conditions were unfavourable. However, the pilot decided to commence the flight and assess the actual enroute weather conditions.

Melbourne Air Traffic Control Radar recorded the track and groundspeed of the aircraft from Lilydale to the area of the accident. The aircraft had passed close to Mangalore Aerodrome, where the cloud base was about 1,500 ft above ground level (agl). It then deviated from the planned track and subsequently penetrated an active military restricted area. Soldiers on the range heard the aircraft approaching and ceased all firing. The aircraft was observed to be flying at about 300 ft agl and clear of cloud. There was no rain in the immediate vicinity and the visibility was reported to be good.

After flying through this and an adjacent restricted area, the track of the aircraft became erratic. During the final minutes of the flight, the recorded groundspeeds varied from 148 kts to 75 kts. The last speed recorded was 138 kts. No radio transmissions were recorded from the aircraft.

Witnesses near the accident site observed the aircraft flying at about 300 ft and reported that the engine noise was particularly loud. Weather conditions were overcast, with the cloud base at about 500 ft and patches of rain and drizzle in the area but not near the accident site. The aircraft was then seen to bank progressively to the left and descend. Impact marks indicated that as the aircraft passed about 140 degrees of bank angle, it clipped the tops of gum trees and then struck the ground. The impact marks and degree of disintegration indicated that the aircraft impacted the ground at high speed.

A detailed examination of the wreckage did not reveal any fault or malfunction with the structure, engine and associated systems of the aircraft which might have led to the accident. The landing gear and flaps were retracted and there was ample fuel on board the aircraft. The weight and centre of gravity were estimated to have been within the prescribed limits.

The area in which the accident occurred was open and relatively flat, with several sites suitable for precautionary or forced landings. Tests conducted in the area indicated that radar coverage existed down to about 250 ft above ground level, with radio communications possible almost to ground level.

The postmortem examination revealed that the pilot had coronary artery disease, but it was not possible to determine whether this had led to an in-flight incapacitation. In addition, the pilot had a history of hypertension, which was controlled by medication. He was also on a weight loss program, which involved taking fenfluramine as an appetite suppressant. Common adverse reactions from fenfluramine include mild sedation, lethargy and giddiness.

The investigation was unable to determine the precise circumstances leading to the apparent navigation difficulties experienced by the pilot, although the weather conditions may have contributed. The behaviour of the aircraft and pilot in the vicinity of the accident site, erratic airspeed, excessive bank angle and failure to take advantage of suitable landing areas, may have been related to the physical problems suffered by the pilot. The onset of any such problems may have been too sudden to permit the pilot to conduct an emergency landing.

Significant Factors

1. Weather conditions were marginal for visual flight.

2. The pilot was probably uncertain of his geographical position.

3. It is possible that the pilot became incapacitated in flight

4. Loss of control occurred at a low height above the ground.

FACTUAL INFORMATION

History of the Flight

At 0700 CST on 23 July 1992, two foreign national pilots, who were undergoing airline transport pilot licence training acquired the keys and documentation for TB20 aircraft VH-LQB in preparation for a daytime instrument flight rules (IFR) navigational exercise.

The aircraft departed at about 0930. After carrying out practice instrument approaches at several aerodromes along the route, they arrived over Ceduna at 1330 where an NDB approach was made before landing. While positioning the aircraft for refuelling a scraping sound was heard from the front of the engine. After the aircraft was refuelled and the engine restarted, the same noise was heard. An examination revealed that the starter motor was remaining engaged. The pilots contacted the operator and requested assistance. The operator despatched a maintenance engineer who replaced the starter motor.

The aircraft commenced taxiing at 1854. The pilot established radio contact with Adelaide Flight Service Unit (FSU) advising that he was taxiing for Parafield, IFR, and would be using runway 11.

A Cessna Conquest, VH-ANJ, commenced taxiing at 1859, with its pilot being unable to see VH-LQB take-off. He reported taxiing to Adelaide FSU and advised that his departure would be from runway 29. Approaching the threshold of runway 11 he noticed the navigation lights of VH-LQB as the aircraft climbed, and estimated the aircraft to have been at 100 to 200 ft above ground level. He then commenced to back track along the runway for a departure to the west.

Witnesses, located to the north of the Flinders Highway, noticed the lights of an aircraft departing from Ceduna Airport, tracking in an easterly direction. Although several kilometres away from the aircrafts track, they believed it was lower than normal, having watched many aircraft depart, including three or four that day. The aircraft lights then descended towards the ground and an orange flame appeared, followed by the sound of an explosion.

VH-ANJ informed Adelaide FSU that they had observed VH-LQB depart, and then saw a fireball appear in that direction. Adelaide FSUs were unable to contact VH-LQB. VH-ANJ was requested to locate the fire when airborne and direct emergency services to it. The fire was located approximately 5 km from the airport, 3 km to the right of runway 11 centre line. It was subsequently identified as the wreckage of VH-LQB.

Injuries to persons

Both pilots of VH-LQB were fatally injured.

Damage to aircraft

The aircraft was destroyed by impact forces and post-impact fire.

Other damage

There was no other damage.

Personnel information

The pilot-in-command held a current Private Pilot Licence with a Class 1 medical certificate, and a Command Instrument Rating for single-engine aeroplanes. He was qualified to fly the TB20 aircraft and had accumulated 61 hours on the aircraft type. His total flying experience was 189 hours, which included 26 hours of instrument flight time, 26 hours of simulated instrument flight time, and 11 hours of night flying experience. He last flew at night on 17 June 1992.

The other pilot held a current Private Pilot Licence with a Class 1 medical certificate, and a Command Instrument Rating for single-engine aircraft.  He was qualified to fly the TB 20 aircraft and had accumulated 65 hours on the aircraft type. His total flying experience was 192 hours which included 38 hours of instrument flight time, and 15 hours of night flying experience. He last flew at night on 14 July 1992.

Aircraft weight and balance

The weight and centre of gravity were within limits at the time of the accident.

Meteorological information

The Ceduna weather was fine with 1 octa of strato-cumulus cloud at 3500 ft. The wind was from 170 to 180 degrees at less than 5 kts. It was reported to be a very dark night with no discernible horizon. Moon rise was not until approximately 0100.

Wreckage and impact information

Ground impact marks indicated that the aircraft had been on a heading of 150 degrees in a shallow dive, with a bank angle of 15 degrees to the right, at an estimated speed of approximately 140 kt when it impacted the ground in an area of open pasture. The right wing separated from the fuselage. The aircraft continued in the southerly direction, breaking up as it went, with the cabin consumed by fire. Propeller contact with the ground caused a torsional failure of the crankshaft at the propeller attachment flange. The propeller travelled in a direction of 210 degrees for 65 m, leaving a trail of slash marks in the ground as it continued to rotate. The engine left wing and other components separated during the impact sequence. The engine bounced away on a curved track to the right for a distance of 110 m in a direction of 240 degrees from the main wreckage trail. The remains of the fuselage, consisting of the fire gutted cabin and tailplane, came to rest 166 m from the initial point of impact.

Fire damage was confined to the cabin area, which was totally consumed, except for the two instrument panels and co-pilot's seat, which were thrown clear.

No evidence was found to suggest a pre-existing defect in the aircraft structure or control systems prior to the accident. The propeller damage, condition of the engine and its components, and specialist analysis of exhaust pipe temperatures at impact, indicated that the engine was delivering power at impact. The temperature of the exhaust pipes was determined to be approximately 500 to 600 degrees Celsius at the time of impact. The vacuum pump frangible coupling, made from a ductile polymeric material, had failed under torsional load. Laboratory examination determined that there was no rotational damage to the failed coupling faces which indicated that the engine ceased operating immediately following the coupling failure.

Medical and pathological information

There was no evidence that either pilot had any medical or psychological condition which might have contributed to the accident.

Fire

A fierce fire, fuelled by aviation gasoline from the ruptured fuel tanks, engulfed the aircraft's cabin, reducing to ash the area between the engine firewall and the tailplane. The remainder of the wreckage suffered little or no fire damage.

Tests and research

Flight profile

A similar aircraft was used to attempt to replicate the accident flight profile from various altitudes. Six flights were conducted. The first flight followed the Ceduna to Adelaide track on climb to a point abeam the accident site. Normal climb power settings and speeds were used. The next four flights used a 10 to 15 degree angle of bank to the right, with the aircraft being held in a dive so as to arrive at the accident site without changing the climb power or trim settings during the descent. The final flight was conducted with power off and the controls left unattended from the top of climb.

The investigation was not able to establish the actual flight profile of the aircraft. However, from the flights it was considered possible that the aircraft may have descended from approximately 500 ft at an indicated airspeed of 140 kts.

The effects of somatogravic illusion were considered. Acceleration after take-off, into a dark horizonless sky accentuates the illusion giving the impression of a steep nose-up attitude. This illusion may cause a pilot to assume that the aircraft attitude is to nose high, and to respond by lowering the aircraft nose. However, studies have shown that this illusion is only likely to have an effect during the take-off rotation and initial climb phase of flight.

Attitude indicator

Tests were later conducted with a similar type of aircraft to establish the time for the attitude indicator to topple following a vacuum source failure.

This was simulated by ground running the engine at 2000 RPM for 5 minutes to ensure the gyro was fully erect, then shutting it down. This test, with a vacuum indication of 4.8 inches of mercury was conducted several times resulting in an indication of a bank to the left.

Gyro instruments

Detailed inspection of the gyro instruments failed to reveal any defects which may have prevented their normal operation.

Additional information

Following replacement of the starter motor the battery was found to be flat requiring the use of an external power source for starting. It was after last light by the time the repairs had been completed, and the pilot who had flown the aircraft to Ceduna carried out the engine run following the starter motor replacement. He then remained in the left pilot seat during the preparations for departure, as it was considered easier to leave the engine running than jump start it again, so by default he became the pilot-in-command for the return flight.

While talking to the pilots prior to departure the instructor who accompanied the engineer to Ceduna did not consider giving them a night operations briefing but was satisfied that they were capable of conducting the flight.

Flight and duty times

On the day of the accident the pilots had planned to complete the exercise during daylight hours. They had commenced duty at 0700, prepared and submitted their flight plan, checked the aircraft, then departed at approximately 0930.  One pilot being in command for the Adelaide to Ceduna sector, the other for the return sector to Adelaide. The flight to Ceduna took approximately 4 hours.

Training

Prior to commencement of night flying training, this operator ensured that all student pilots received classroom instruction in night flying techniques. In the syllabus of training the operator also covered the subjects of somatogravic and other illusions which can effect pilots under limited visual conditions.

The initial night flying training was carried out at Parafield, and students were subsequently taken to country airports, away from the lights of built-up areas, so they could experience dark night operations.

ANALYSIS

Following an apparent normal take-off the aircraft then descended back into the ground in what appeared to be controlled flight.

It is unlikely that the aircraft was lower than 500 ft above ground level when it commenced the descent. At this height the effects of acceleration and therefore somatogravic illusion would not be experienced by the pilot.

After becoming airborne the pilot may have become involved in recording the departure time, making a departure call on the CTAF, and changing to the Adelaide FSU frequency to advise them of the departure and next estimate, while failing to give sufficient attention to flying the aircraft.

At departure the pilots had been on duty for 12 hours, and it is possible that fatigue may have contributed to the accident.

The reason for the accident could not be established.

The pilot was conducting a rice sowing operation and had entered the procedure turn on completion of the first swath run of his first load for the day. The aircraft appeared to be operating normally at about 300 ft, however, as it turned back towards the treatment area it was seen to overshoot the alignment for the reciprocal swath run. The nose then pitched down, and the engine noise was heard to increase significantly as the aircraft descended to the ground at a steep angle.

A small fire in the engine area was extinguished by the two markers, who arrived from the treatment area within minutes of the impact.

The aircraft had struck the ground in a left wing low, steep nose-down attitude. The left wing folded up against the fuselage and the engine was displaced to the right. Impact forces were high, causing major disruption to the fuselage, although the cabin area dimensional and structural integrity remained substantially intact.

No evidence of a pre-impact failure was found in the aircraft or its systems.

The weather conditions were fine and calm.

Findings

1. In an attempt to regain the alignment for the reciprocal swath run, the pilot tightened the turn, causing the aircraft to stall and enter an incipient spin to the left.

2. The height available was insufficient to permit the pilot to regain control of the aircraft.

Significant Factors

1. The aircraft stalled at a height from which the pilot was unable to effect a recovery.

Safety Action

During this investigation it was identified that the aircraft was fitted with an American Safety Inertia Reel Pt No 7260111-405 which does not comply with the requirements of CAO 101.17 for agricultural operations.

It is therefore recommended that the Civil Aviation Authority:

1. Advise agricultural operators that American Safety Inertia Reel Pt No 7260111-405 does not meet the requirements of CAO 101.17 para 5.9.3, and

2. Take steps to ensure that inertia reels which are fitted to aircraft engaged in agricultural operations do comply with the requirements of CAO 101.7 para 5.9.3.

On 19 June 1992, at approximately 1853 hours, a Beechcraft Baron 95-B55, registration VH-JDL, disappeared from Air Traffic Control radar display, without prior indication of difficulty. The aircraft wreckage was located the following morning on a moderately timbered slope, 700 metres above mean sea level and 45 kilometres north-east of Canberra, Australian Capital Territory.

The pilot and all five passengers were killed and the aircraft was destroyed by impact forces. The investigation determined that the aircraft departed Bankstown Airport loaded in excess of the maximum allowable take-off weight, and that the pilot did not comply with either Instrument Flight Rules or Night Visual Flight Rules rating recency standards required for the conduct of the flight.

While cruising at 8,000 feet, the aircraft entered a rapid descent, during which it reversed direction in a left turn. The descent was briefly arrested at a low altitude, however, the aircraft again turned left and descended rapidly. The aircraft exhibited flight characteristics consistent with those of an aircraft loaded to an aft centre of gravity position. There are indications that the centre of gravity moved further aft during the flight, until reaching a point at which the pilot was unable to prevent significant diversions in both climb and descent from the reference altitude, culminating in the rapid descent.

At approximately 2145 hours on 28 August 1983, in the course of a planned charter, Instrument Flight Rules night flight from Windorah to Toowoomba, Beech 200 Super King Air aircraft VH-KTE broke up in flight and crashed to the ground 3.5 kilometres south of Adavale, 201 km from Windorah, and on the aircraft's planned track. The pilot-in-command and the 11 passengers were killed when the aircraft fuselage, devoid of wings and empennage, impacted the ground, inverted. The Adavale police officer reported the accident to the duty officer of the Department of Aviation, Queensland Region. An investigation team from the Bureau of Air Safety Investigation assembled at Adavale on the morning of 29 August 1983.

Detailed examination of the burnt-out wreckage disclosed no evidence of any defect or malfunction which might have contributed to the accident. A loss of tail rotor effectiveness occurred for reasons which have not been determined.

The pilot was a member of the RAAF Richmond Gliding Club and was attending a camp, held annually by the club at various locations in western New South Wales, to gain experience at cross-country gliding.

Examination found no evidence of mechanical defect or malfunction which might have contributed to the accident. There was no evidence of pilot incapacitation.

VH-IQY was working, in conjunction with a number of stockmen on horses or motorcycles, to muster cattle some 20 km northwest of the station homestead. At about 1040 hours, the aircraft made a number of steep dives to tree-level, apparently to move cattle adjacent to a creek. After the last dive, it was observed to pullup to an estimated height of 400 feet, then stall and dive to the ground.

At approximately 1853:30 hours EST on 10 July, 1978, Partenavia P68B aircraft registered VH-PNW, with a crew of two and one passenger aboard, became airborne from Runway 26 at Essendon Airport, Victoria, and climbed to a height of 200 to 250 feet. Co-incident with the raising of the wing flaps from the take-off position and a simulated failure of one engine, the aircraft assumed a nosedown attitude and continued straight ahead on a descending flight path. The aircraft crashed into houses 286 metres beyond the western end of the runway. Six persons on the ground were killed, and one person received minor injuries. The aircraft was destroyed and the three occupants were seriously injured.

Pilot allowed glider to descend out to sea. Stalled at low speed, diced steeply into sea.