David Learmount / Washington DC

North America and western Europe's accidents fall as levels for rest of world stagnate

The difference in controlled flight into terrain (CFIT) risk between world regions is large and growing fast, a new study reveals. CFIT remains the accident category accounting for more fatalities than any other, having killed over 3,000 people in the past 12 years in crashes involving 53 large commercial aircraft, according to Honeywell chief engineer Don Bateman.

In the same period, 270 smaller turbine aircraft and 360 piston aircraft have been lost to CFIT, he says. Meanwhile, for large jet aircraft registered in North America and western Europe, the risk of CFIT has been reduced by a factor of 100 since 1975 to one in 93 million flights, according to the study by Bateman presented at the 10-13 November Flight Safety Foundation seminar in Washington DC. This compares with the rest of the world, where the risk is "stagnant" at one in 16 million flights. The risk is unchanged since 1975 in "many parts of Asia, South America and Africa", he says.

Bateman attributes part of the improvement to the fact that terrain awareness warning systems are compulsory in North America and western Europe, and the fleet equipage rate for large aircraft registered there is much higher.

Bateman says airport or terminal area air traffic controllers often seem concerned with traffic separation to the exclusion of local-area terrain awareness. He cites a Boeing 737-300 leaving Las Vegas in December 2002, for which the departure controller was supposed to be giving a radar vectoring service, but he left the aircraft continuing towards terrain until its pilot was warned by its enhanced ground proximity warning system (EGPWS).

Controllers with the minimum safe altitude warning system (MSAWS) CFIT prevention tool do not always use it. A Philippine Airlines Airbus A330 on approach to Agana, Guam, in December 2002 missed Nimitz Hill by a few metres after a GPWS warning. Bateman says the controller received an MSAWS warning but cancelled it without warning the pilot.

Source: Flight International