David Learmount/LONDON

THE AMERICAN Airlines Boeing 757 crash in Colombia on 20 December contributed to a plunge in world airline-safety figures during the last six months of 1995, following the most promising first half-year period in history. Provisional figures show that there were just over 1,200 deaths in around 60 fatal accidents during the year.

Worldwide analysis of 1995 shows that 585 people died in nine fatal accidents on jet-powered scheduled flights, with four of those accidents and 382 of the fatalities occurring in December alone. There were 353 fatalities in nine accidents involving non-scheduled passenger aircraft. Regional and commuter airlines suffered 24 fatal accidents in which a total of 220 people died, while 16 accidents to cargo flights accounted for 40 aircrew deaths.

The American 757 crashed into a 12,000ft (3,600m) mountain near Cali, Colombia, killing all 160 people on board. The accident has already been attributed by the US and Colombian authorities to aircrew error. Now US Federal Aviation Administration Administrator David Hinson has ordered a review of American Airlines' pilot training and cockpit procedures. Colombian accident investigators confirm that the 757 crew failed to carry out a pre-descent approach briefing or checks. Cali Airport is in a steep-sided, north/south-orientated valley.

The co-pilot first called Cali air traffic control (ATC) when the flight was 63 miles north of the Cali VHF omni-range/distance measuring equipment (VOR/DME) navigation beacon, descending to 20,000ft. He received clearance to descend to 15,000ft and proceed direct to the Cali beacon. This is south of Cali airport and is the key beacon in a VOR/DME step-letdown to the runway (01/19). The northbound runway direction (01) is normally used because it has an instrument-landing system. The 757's autopilot was engaged and the flight-management system (FMS) selected to the lateral navigation mode. ATC has no effective surveillance radar once aircraft reach mountaintop level - about 15,000ft.

Because the airport wind was calm, the controller offered the crew an approach to the southbound runway (19). The crew accepted, and was cleared for "the VOR/DME 19 Rozo One arrival", and told to report reaching Tulua VOR. Tulua, 63km (34nm) north of Cali Airport, marks the start of the Rozo One VOR/DME approach; Rozo is a non-directional navigation beacon on the approach 5km north of Cali Airport.

The aircraft, however, had already passed the Tulua beacon, but the pilots apparently did not realise this.

The crew requested clearance direct to Rozo and then "...do the Rozo arrival". ATC had said, after some further exchanges, "...affirmative, direct Rozo One and then runway 19", but repeated that the crew had to report over Tulua first.

ATC advised that, after Tulua, the approach consisted of reaching 5,000ft by 21nm DME [from the Cali beacon].

Meanwhile the crew continued descent through the cleared 15,000ft, with airbrakes selected to increase the rate of descent. When they finally entered Tulua on the FMS, the aircraft began a fatal 90s left turn (initially eastward), to return to the beacon.

Then the pilots selected heading mode on the FMS and turned the aircraft right. The aircraft hit the mountain with the ground-proximity-warning system ordering "pull-up". The airbrakes were still deployed.

Full analysis of 1995 world airline safety will appear in Flight International, 17-23 January

Source: Flight International