Air Transport World

An incomplete solution. (Airports & Airways).(Standardization of air traffic control procedures)

Standardization and harmonization of TCAS/ACAS procedures around-the world, plus increased attention to cultural factors, is vital if the systems are to succeed to the full extent of their lifesaving functions

It is extremely unlikely that the pilots of the DHL 757-23APF and the Bashkirian Airlines Tu-1 54M saw each. other in-the final seconds-before they collided in the night sky over southern Germany last July 1. However, it is not so much what the pilots saw that will be the subject of extensive discussion and second-guessing, it is what they heard--and how they responded.

There is no argument that both cockpits received audible conflict warnings from their respective L-3 TCAS II Change 7 devices and that the DHL pilot was instructed to descend and the Bashkirian pilot to climb according to the solution devised by the systems to avoid the impending midair. In fact, each received further advisories to "increase descent" and "increase climb" respectively just 8 sec. before the crash., But the Tu-154M captain, Alexander Gross, 57, also heard Zurich ATC instructing his crew to descend not once but twice in contradiction to the TCAS advisories, and it was these instructions he chose to follow with fatal results.

The probable cause of the tragedy, in which 71 persons died including 52 children, is still. under study and a final report is months away. Much of the focus no doubt should and will be on the performance of the Swiss privatized ATC organization Skyguide and what appear to be a series of lapses on the part of that organization that placed the airplanes in harm's way. The information that emerged shortly after the disaster includes reports that only one controller was on duty, that only one phone line was operational and that the short-term conflict alert system was down for maintenance. …

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