Introduction
This analysis was conducted on the 75 fatal aeroplane accidents which occurred in the period 1 January 1988–31 December 1990. Seventy-four accidents involved general aviation aircraft and one accident involved a regional airline aircraft. One hundred and sixty-two deaths resulted from the accidents. Most of the accidents (57 of 75) involved single-engine aircraft. Accidents to rotary wing aircraft, gliders and sport aviation aircraft were excluded.
Type of operation
The largest proportion of accidents occurred on flights categorized as private or business. One accident in the sample occurred on a regional airline flight (low capacity airline).
Type of occurrence
Many accidents involve a sequence of events. The following graph indicates the first event in the accident sequence. Each event may have been followed by further events not reported here. For example, an aircraft which sustained an engine failure may have then been involved in a hard landing. The most frequent first event leading to fatal accidents was loss of control. The next most frequent first event was collision with terrain, control unknown where the investigation could not determine whether the pilot was in full control of the aircraft. Controlled impact with terrain refers to accidents in which the aircraft struck terrain while apparently under the control of the pilot. Such accidents typically occur in conditions of reduced visibility. Collided with object (not wires) includes cases in which an aircraft collided with trees, buildings or other obstructions. Collision with power lines is treated separately under wire strike.
Broad accident factors
Seventy-two per cent of the accidents were judged to involve pilot factors. Weather was a factor in 17% of the accidents. Other personnel contributed to 12% of the accidents. Other personnel refers to people other than the pilot of the aircraft, and includes air traffic controllers, other flight crew and maintenance workers. Note that accidents may be assigned multiple factors.
Pilot factors
Figure 4 indicates the most frequent pilot factors in the sample of accidents. The most commonly assigned factor was poor judgement. Other common factors were in-flight decisions or planning and attempted operation beyond experience or ability. These results are consistent with the general worldwide finding that inadequate decision making contributes to a large proportion of accidents in general aviation and airline operations. Examples of inadequate decision making or poor judgement are knowingly continuing a flight into adverse weather, engaging in unauthorized low flying and continuing a flight with a known low fuel state. Medical factors were relatively rare. These factors included mismanagement of fuel system and selected unsuitable area for landing or takeoff.
Further detail on human factors terminology
Poor judgement
For many years it was assumed that good judgement was an inevitable by-product of flying experience. However, the data that BASI has accumulated indicates that errors of judgement are made by experienced and less-experienced pilots alike. Airlines around the world recognized in the 1970s that even experienced crews could make serious errors of judgement. For example in 1979, the crew of a United Airlines DC8 were distracted for so long by a landing gear problem that they eventually ran out of fuel1. Many major airlines have now introduced crew resource management (CRM) training to ensure that flight crew apply principles of judgement and teamwork. However, for general aviation and regional airline operations, pilot judgement continues to be a significant accident factor. In the 1980s, the Australian Department of Aviation and equivalent bodies in the USA and Canada sponsored the development of judgement training courses for pilots. The results indicated a significant reduction in aircrew errors 2)In 1987, the US Federal Aviation Administration (FAA) released a series of manuals