Four significant investigation reports on accidents from previous years have been published in the past six months.
Chronologically, these were the October 2001 SAS Boeing MD-87 collision with a Cessna Citation CJ2 on the runway in fog at Milan Linate airport, Italy; the November 2001 Crossair BAE Systems Avro RJ100 crash on approach to Zurich airport, Switzerland; the 1 July 2002 mid-air collision between a Bashkirian Airlines Tupolev Tu-154 and a DHL Boeing 757 freighter over Uberlingen, southern Germany; and a FedEx Boeing 727C accident on 26 July 2002.
Both the Crossair and FedEx events were controlled flight into terrain (CFIT) accidents that occurred during final approach at night. The first was a VOR/DME non-precision approach in poor visibility with light snow; the second was a night visual approach in good weather. They both hit tree tops with not far to go to the runway and both crews, according to the reports, had allowed their aircraft to get well below the approach profile they should have flown. No-one was killed in the FedEx accident, although the aircraft was written off by impact damage and fire, but in the Crossair accident 24 people died. The US National Transportation Safety Board attributed the FedEx accident to a combination of factors, including crew failure to follow procedures; insufficient crew cross-monitoring; fatigue; and the co-pilot's colour blindness, which impaired his ability to read the precision approach path indicator lights.
In the Crossair report the crew and the airline were heavily criticised, but if the flight arrival had been 6min earlier it would have been possible to carry out a precision instrument landing system approach to the main runway and an accident might have been avoided. Because of a curfew on that approach, the crew was required to reposition the aircraft to another runway for a VOR/DME non-precision approach.
The only party in the Milan Linate runway incursion collision to be uncensured by the Italian inquiry was the SAS crew, which had been cleared to take off when it hit a Citation CJ2 that had taken an uncleared taxi route, effectively got lost and entered the runway in fog. All 110 people on board the MD-87 were killed, as were the four aboard the CJ2 and a number of people in the cargo centre. The entire Linate air traffic control and operational system was criticised. The report found that virtually no systems or practices at Linate followed approved procedures or worked as they should and, by implication, all the Italian safety oversight agencies were also slammed.
In the case of the Uberlingen mid-air collision, the only participants to avoid criticism were the DHL crew. When their airborne collision avoidance system (ACAS) provided a resolution advisory requiring descent, the pilot complied and advised air traffic control. The Bashkirian pilot's actions were criticised because he followed a last-minute ATC instruction to descend when his ACAS had advised him to climb, although at that time in Russia, where a minority of aircraft were ACAS-equipped, the standard procedure was to follow ATC instructions if there was a clash. That has now been changed in Russia and international practices have been clarified. When both aircraft descended, they collided, and all 69 people on the Tu-154 and both pilots on the 757 freighter were killed.
Meanwhile, the Swiss air traffic services provider Skyguide, responsible for the separation of the two aircraft that collided, faced a long list of recommended changes to working and organisational practices and was censured for not operating a safety standards monitoring system, even though it had one.
Source: Flight International
