Human Failings Underscored In Report of 2002 Mid-Air Collision Over Germany

Air Safety Week,  May 31, 2004  

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The countdown to collision reads like a slow-motion movie of impending disaster. As an historian once said, history is written in retrospect but is lived forward, so one can know the end but never know what it was like in the beginning only. Knowing the end in this case, however, makes the transcript of events all the more sobering. Because the apparent size of another aircraft remains small, until "exploding" into view moments before impact, the pilots may not have been aware of their mortal peril until only a second or two before impact.

Using the classical "Swiss cheese" model of accident causation, numerous defenses against disaster were penetrated. The BFU report dwelled critically and at some length on the safety breaches. We focus here on three of the many issues raised by the BFU. First, regulations published by the International Civil Aviation Organization (ICAO) and other national regulatory bodies were "not standardized, [were] incomplete and partially contradictory. The BFU said that in its opinion, "only one procedure can be permitted in the case of an RA." If air traffic control issues a conflicting instruction, follow the RA and advise ATC accordingly. (ASW note: refer to the latest regulatory activity regarding TCAS, advising pilots to ignore an RA fail indication and to comply with RA aural guidance, injecting a comparable level of potential confusion evidenced in this mid-air collision; see ASW, May 24, and April 19. See also May 21 item in table).

Second, the guidance in the TU154 manual described TCAS as an additional system for indicating intruder traffic and that ATC is the basic system for collision avoidance. The BFU said, "This reference devalues the TCAS system's priority, as it indicates the TCAS is a back-up when ATC is not available, and not a last resort defense .... even in the presence of full ATC services."

Third, CRM training does not appear to be achieving the desired effect. Even though the Russian PIC was a CRM instructor, he made his decision to descend in a peremptory manner, and continued the descent even though the copilot twice questioned the decision in the face of the conflicting RA alert to climb. Whether CRM training is having the desired effect on cockpit decisionmaking has been raised recently in this publication (see ASW, Jan. 26).

A few additional comments are in order. Skyguide and other European ATC service providers have since banned the previously tolerated practice of sleeping on night shifts. The first principles of ATC require supervision, backup and anticipation to be consistent and continuous. The fact that ongoing maintenance on the night of the accident was going to undermine efficiency and safety simply was not factored into the staffing situation and the condoned sleeping on watch. A report issued by the German regulatory authority, the Luftfahrt-Bundesamt (LBA), a year before had found SkyGuide radar equipment, training and procedures to be wholly deficient. SkyGuide has since tightened ship, but the needed changes occurred after the accident.