Executive summary
Australian aviation is, by world standards, extremely safe. Fatal accidents in regular public transport (RPT) operations are low and, since the late 1960s, have been confined to low capacity operations. Australia has not had a high capacity RPT fatal accident since 1968 and has not had a RPT jet fatal accident.
The vast majority of Australian civil fatal aircraft accidents occur in general aviation (GA) operations. This study examined Australian ‘VH-registered’ civil aircraft involved in GA fatal accidents for the period 1991 to 2000, and covers fatal accident numbers and rates by aircraft type and operational grouping, timing of accidents, injury levels, pilot demographics and fatal accident types.
Between 1991 and 2000 inclusive, there were 215 fatal accidents and 413 associated fatalities. Over the ten-year period there were 1.2 GA fatal accidents per 100,000 hours flown. The annual fatal accident rate decreased from 1.6 fatal accidents per 100,000 hours flown in 1991 to 0.9 in 2000. While this decrease was not statistically significant, subsequent data to the end of 2002 do indicate a statistically significant decrease. Statistically significant variations were identified at certain times of the day and week, indicating that occurrences were more likely to be fatal accidents at certain times. The rate of general aviation fatal accidents was found to be significantly higher during the evening between 1700 and 2059 than the rest of the day and the private/business fatal accident rate was found to be significantly higher over the weekend than during the week. Reasons for these findings could not be clearly identified.
The population of pilots involved in fatal accidents was compared with the present population of active general aviation pilots against certain demographic criteria.
The risk of a fatal accident per hour flown was greater for pilots who had between 50 and 1,000 hours aeronautical experience than pilots who had more than 1,000 hours experience. However, with the low number of pilots involved in fatal accidents, small changes in the demographics of pilots involved in fatal accidents can lead to large changes in the risk associated with different age and experience groupings.
The fatal accidents were grouped using a classification scheme developed within the ATSB so that a consistent and useful description of the accident types could be achieved. The re-classification and re-coding of the accidents enabled a more accurate description of the larger groupings of fatal accidents, which could provide a greater opportunity to accurately target specific risk areas in general aviation operations.
The majority of fatal accidents (82 per cent) fell into three main groups:
- controlled flight into terrain
- managed flight into terrain
- uncontrolled flight into terrain.
For the purpose of this report these accident types were defined as:
- Controlled flight into terrain (CFIT) - an event where an aircraft collided with obstacles, objects or terrain during powered, controlled flight with little or no awareness on the part of the pilot of the impending impact.
- Managed flight into terrain (MFIT) – an event where an aircraft collided with obstacles, objects or terrain while being flown under limited control or reduced performance, with insufficient height/performance to reach a designated landing area.
- Uncontrolled flight into terrain (UFIT) - an event where an aircraft collided with obstacles, objects or terrain after control of the aircraft was lost in-flight (includes cases where the pilot became incapacitated) but the aircraft structure did not change prior to impact.
UFIT fatal accidents were the most prevalent of the fatal accident types (46 per cent), followed by CFITs (30 per cent) and MFITs (6 per cent). Accidents that did not fall into one of these three main groupings were categorised separately, but were not sub-categorised to the same extent.
The vast majority of low-level UFIT fatal accidents (approximately 90 per cent) could be described as accidents where the pilot’s control inputs (or lack of inputs) initiated a loss of control. In almost a quarter of these cases, turbulence or windshear may have also contributed to the loss of control. In contrast, UFIT fatal accidents during ‘normal’ operations were more likely to have had an initiating factor such as a loss of engine power, loss of reference to the external environment, aircraft system or airframe problem, pilot incapacitation etc., with around 20 per cent being primarily the result of pilot action or inaction. This disparity suggests that many of the loss of control events during low-level operations could have been recovered had the aircraft been at a greater height. For fixed wing operations, a higher proportion of UFIT accidents were private/business operations (2/3), compared with MFIT or CFIT accidents (1/2).
The next largest fatal accident grouping was controlled flight into terrain accidents (CFITs). The majority of CFIT fatal accidents occurred during low-level operations, when the pilot could see the environment. Most of these accidents were wirestrikes. Pilots involved in CFIT fatal accidents who were flying aircraft unnecessarily low, accounted for a quarter of all the fatal CFITs and 42 per cent of fatal CFITs during low-level flying. The large majority of CFIT fatal accidents from ‘normal’ operations occurred when the pilot was not able to see the outside environment, whether operating under VFR or IFR.
The accident classifications used in this report promote greater understanding of the types of fatal accidents that have occurred by focusing on the state of the aircraft at the time it sustained damage or a person was fatally injured. The events or circumstances that precipitated the accident types highlight areas where it is possible to intervene in the sequence of events to avoid a fatal accident or reduce the severity of an accident.
The characteristics of each accident group were markedly different, and the sub-categorisation of accidents within each group was therefore also different. The majority of CFIT fatal accidents were initiated by an impact with an obstacle or terrain. In UFIT accidents the event that led to the situation becoming a fatal accident generally happened while the aircraft was still flying. MFIT accidents were generally fatal because of the nature of terrain encountered at the time of impact, rather than because of the nature of the event that precipitated the accident.