The greatest gains in reducing aviation accidents could be achieved by reducing skill-based human errors, according to a new report on human factors by the Australian Transport Safety Bureau (ATSB).

Improvements in aeronautical decision-making and the modification of risk-taking behaviour could also reduce aviation fatalities, the ATSB says.

The study looked at the type of human errors in Australian civil aviation accidents and compared the results with a sample of accidents in the USA. The bureau found that while the types of accidents between the two countries varied, the pattern of aircrew errors was remarkably similar.

In both countries skill-based errors were the most prevalent, followed by decision errors, violations and perceptual errors. Further study is needed to determine which skills need improving, the ATSB suggests.

Meanwhile, the bureau has found that the average age of the Australian fleet of turbofan aircraft is low and continuing to decrease, while the average age of the country's piston engine fixed-wing fleet has risen to 30 years.

While the average age of many aircraft in the country is increasing, this should not affect their safety if quality maintenance systems are in place, says the bureau. However, it suggests that the high average age of multi-engine piston aircraft needs to be considered in relation to their safe operation in passenger services.

The average age of turbofan-powered aircraft used in regular passenger transport operations - in the 50,000-100,000kg (110,000-220,000lb) category - is low at six years. This figure is two years lower than that found in the last study in 1995, thanks largely to the expansion of Qantas and the use of new aircraft by Jetstar and Virgin Blue, says the ATSB.

In the larger turbofan-powered aircraft category, above 100,000kg, the fleet is on average 11 years old.

The country's turboprop fleet, which primarily operates on low-capacity airline services, has an average age of 18 years - two years older than in 1995. Additional and specific maintenance is key to ensuring that these aircraft meet the necessary airworthiness standards for passenger operations, says the ATSB.

The oldest aircraft are the piston-powered aircraft, including small single-engined aircraft used by flying schools and private operations and twin-engined aircraft used in charter and low-capacity operations. These aircraft are on average 30 years old and do not receive the same level of ongoing support from manufacturers as turbo­fan-powered aircraft.

The ageing aircraft population in the country requires co-operative approaches by operators, manufacturers and regulators to ensure any defects are notified to the industry, says the ATSB. "If quality maintenance systems are in place, ageing aircraft need not lead to reduced safety," it adds.

Source: Flight International