Analysts trying to identify the secret of Western carriers' success in reducing their accident rate to almost nothing generally conclude it is the result of a combination of factors: greater engine and systems reliability in the generation of aircraft produced since the early 1980s; improved cockpit technology that has provided flightcrews with better situational awareness - once they have become accustomed to working in a digital cockpit - and technological advances such as the enhanced ground proximity warning system (EGPWS), generically known as a terrain awareness and warning system (TAWS).

In addition, crew resource management is now an accepted part of airline pilot training culture, with few exceptions, even though its wider introduction was greeted with scepticism 20 years ago.

These are all probable factors in improved safety, as is the use of flight operations data monitoring (FODM) - known in the USA as flight operations quality assurance (FOQA). It has long been recognised that modern aircraft have a better safety record than those built before the advent of the glass cockpit, but analysts say there is now a measurable difference between the safety rates of Western airlines that have been using FODM for many years and those that have not.

Don Bateman, chief engineer of EGPWS manufacturer Honeywell, has kept a database of GPWS warnings and CFIT accidents for many years. Since EGPWS was fitted, he says, there have been more than 30 incidents in which the equipment provided "timely warning" of terrain to the crews. These might otherwise have become 30 CFIT accidents.

TAWS is compulsory for all aircraft operated by airlines in Europe and North America, and Honeywell says it has now delivered 30,000 systems. The equipment has been standard on all new Airbus and Boeing aircraft for many years but, according to Bateman, the retrofit rate "in many parts of Asia, South America and Africa" is low. He observes that although the CFIT risk has been reduced by a factor of 100 in North American and western European airlines, down to one in 93 million flights, the risk level remains "stagnant" in much of the rest of the world at a level of one in 16 million flights.

In the case of the only two probable CFIT events this year - according to data currently available - both aircraft were twin-turboprop commuters in which EGPWS is not required.

Source: Flight International