Sequence of events
The Cessna A152 Aerobat aircraft was engaged on an aerobatics training flight with the pilot the sole occupant of the aircraft. The pilot was practising for an aerobatic competition and had been having problems conducting stall turn manoeuvres.
Before the accident flight, the pilot had completed an aerobatic practice flight with an instructor. The pilot then decided to fly a solo flight to practise stall turns without the effect of a second person's weight on aircraft performance in aerobatic manoeuvres. He then intended to practise his full aerobatic sequence, which the instructor later stated was well within the pilot's capabilities. Between flights the pilot refuelled the aircraft and consumed a bottle of soft drink.
After takeoff for the solo flight, the pilot discussed with his instructor by radio, his intentions for the flight and the criticisms of his manoeuvres during the dual flight. The instructor later reported that during the discussion, everything concerning the pilot and the aircraft seemed normal.
Witnesses some distance away heard the aircraft fly over. They later heard a thump and noticed smoke rising from the same direction as the source of the sound. There were no witnesses to the impact.
The wreckage was contained within a relatively small area, apart from two sections of fuel tank and the associated wing that were found about 40 m away. Most of the aircraft had been consumed by a post-impact fire.
Examination of the accident site revealed that the aircraft had impacted the ground in balanced flight at high speed in an attitude of approximately 70 degrees nose down. The engine was producing high power at impact. Examination of the wreckage did not reveal any technical defect that would have contributed to the accident.
The pilot was 61 years of age and had been flying since 1979. He held a Private Pilot Licence (Aeroplane), and a valid Class 2 medical certificate. He had accrued a total of 893.3 hours flying experience, including 7 hours in the last 90 days, probably all on type. In the last 30 days, he had flown 1.3 hours, all on the day of the accident. Since 1982, the pilot's principal interest had been aerobatics, and in recent years he had become involved in competition aerobatic flying. Since November 1994, he had held a CASA approval to conduct aerobatics down to 1,500 ft AGL. He had completed his most recent biennial flight review on 26 June 2000.
The pilot had a long history of hiatus hernia and taken medication for it but had not undergone surgery. At the time of the accident, he was not taking prescribed medication. For about 10 years, he had been prone to fits of coughing after eating and drinking. During these attacks, his ability to perform other tasks was impaired. About 45 minutes before the dual flight, the pilot had eaten a burger and chips. During the dual flight, he had suffered a fit of coughing during which time his attention to flying the aircraft was reduced.
Toxicological examination of the pilot revealed the presence of the drug doxylamine, at a concentration of 4.7 mg/kg in the liver. The finding was reported as `semiquantitative' with a possible error of 20 percent. However, regardless of any error, the pathologist regarded the concentration as sufficiently high to possibly affect the pilot's ability to fly the aircraft.
Medical information revealed that makers of pharmaceutical products usually include doxylamine with other agents such as paracetamol and codeine in strong analgesic medication for such conditions as migraine. In isolation, doxylamine is classified as an anti-histamine, but it has strong anti-emetic properties useful for treating motion sickness, nausea and similar conditions. It is also a drying agent used in a number of non-prescription cold and flu preparations. However, either alone or in conjunction with other substances, doxylamine can cause drowsiness, visual disturbance and can contribute to disorientation.
The reason for the loss of control of the aircraft could not be positively established. Pilot incapacitation leading to a loss of control was a likely factor.
Due to his medical condition, the pilot might have suffered a coughing fit in flight that impaired his ability to fly the aircraft. Alternatively, the concentration of doxylamine in his system might have led to drowsiness or even disorientation associated with aerobatic manoeuvres. Other possible reasons for a loss of control of the aircraft include pilot incapacitation for some other reason, and loss of consciousness, or partial loss of consciousness, due to the onset of g loadings when conducting an aerobatic manoeuvre.
- The pilot suffered from a medical condition that could have adversely affected his ability to fly the aircraft.
- The pilot lost control of the aircraft and did not regain control before the aircraft impacted the ground.
|Date:||12 September 2000||Investigation status:||Completed|
|Time:||1805 hours ESuT|
|Location:||9 km NW Inverell, Aero.|
|State:||New South Wales||Occurrence type:||Collision with terrain|
|Release date:||02 October 2001||Occurrence class:||Operational|
|Report status:||Final||Occurrence category:||Accident|
|Highest injury level:||Fatal|
|Aircraft manufacturer||Cessna Aircraft Company|
|Type of operation||Private|
|Damage to aircraft||Destroyed|
|Departure point||Inverell, NSW|
|Departure time||1800 hours ESuT|
|Role||Class of licence||Hours on type||Hours total|