David Learmount/LONDON
Airline safety is improving more quickly than traditional statistics indicate, says a study by Airclaims in association with the European Union.
The annual number of aircraft totally destroyed in airline accidents has been steady since 1970, despite a 350% expansion of the world fleet and an increase in the number of flights from 6.8 million to 18.8 million, says Airclaims, one of Europe's leading loss adjusters.
Air accident statistics based on hull losses alone are not an accurate reflection of flight safety, Airclaims director of air safety Paul Hayes points out, because older aircraft are often written off by insurers despite receiving relatively slight damage. The proposed new risk-evaluation method separates those aircraft totally destroyed from the other "hull losses" which were merely uneconomic to repair.
For example, last year there were 24 hull losses involving Western-built jet airliners, but only 15 of the aircraft were destroyed. In 1958, however, there was little difference between the annual numbers of aircraft destroyed compared with hull losses, whereas "in recent years" the difference between the two figures has been growing.
To make accident assessments reflect accurately the seriousness of accidents, Airclaims proposes a system of assessing "percentage damage". Since aircraft age differs at the time of accidents, the "economic loss" resulting from damage is factored to assume that they are new when the accident occurs, which better reflects the seriousness of the damage and therefore of the accident.
Airclaims is using the percentage damage system to assess over 1,000 airliner accidents since 1970. Whereas traditional assessment declared 50% of the aircraft write-offs, the "percentage damage" formula determined that only 40% were destroyed, indicating a 20% safety improvement when damage severity is taken into account.
Since 1970, says Airclaims, the annual number of hull losses has increased slowly, "perhaps by about one every five years", but the trend for aircraft destroyed is flat. Taking into account industry growth, in 1970 the trend was for an aircraft to be destroyed every 500,000 flights, but now the rate is one in every 1.3 million, Airclaims says.
Similarly, in 1970 a jet airliner faced a risk of one accident with 10% or more damage about every 300,000 flights, but now the trend for 10% damage accidents is one in every 500,000-600,000 flights.
Source: Flight International
