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

Air Safety Week, May 31, 2004

While a bit of conjecture, had the TU154 leveled at its assigned altitude of 35,000 feet, it would appear according to the detailed graphs in the BFU report that the B757 would have passed closely overhead by about 50 feet (a miss by that amount being as good as a miss by a mile, practically speaking). As it happened, the TU154's attempt at climbing back to the assigned level made matters worse, the collision occurring at 34,890 feet. The TU154 not only failed to comply with the TCAS RA but also then failed to level off accurately at its assigned altitude.

Training trumps culture

Too much should not be read into simplified perceptions of an authoritarian Russian "culture." Why did the Russian crew feel it necessary to follow ATC instructions and disregard TCAS? The crew was very experienced, but with the absence of a simulator they had not been trained on the mandatory reaction protocols associated with TCAS. This situation recalls the lack of training concerning the B747 para-visual display (PVD) cited by the Aviation Safety Council (ASC) of Taiwan in its investigation into the fiery October 31, 2000, takeoff crash on the wrong runway of Singapore Flight SQ006 (see ASW, March 5, 2001).

Further, the operating procedures for the flight crew specifically required compliance with ATC at all times. It was not Russian "culture." It was poor, incorrect or absent training.

Big sky - little sky

This tragic case should end the "big sky" notion that the air traffic controller's ultimate savior will be the vastness of the airspace and the smallness of the airplanes. Satellite navigation accuracy, RVSM and automated, computerized flight controls have combined to kill the big sky theory. Dense clusters of airplanes headed in both directions and separated by half the 2,000-ft. vertical separation of yesteryear can make the sky along preferred tracks very small. Constructing a mid-air collision is now as straightforward as putting two trains on one set of tracks. In this accident, the controller tried to close the switches after the locomotives had passed by on their intersecting tracks. Technical refinement of navigational tracking accuracy and heightholding precision has increased the efficiency of preferred airspace use, but at an increase in the risk of mid-air collisions. Controllers now need to become sensitized to the "small sky" theory. For pilots, the "see and avoid" principle of collision avoidance may no longer be sufficient.

The 'strange attractor'

For pilots, sighting the threat can lead to a greater hazard that might be called the "strange attractor." This term describes a scenario where two pilots at night without a defined horizon become fixated on keeping each other's lights in sight. In this mid-air collision, note that the TU154 changed its heading from 264[degrees] to 274[degrees] about two seconds after sighting the B757. The result can be a mutually maintained constant relative bearing on each other, which can greatly increase the risk of collision or near-miss. The control inputs by both pilots in the last few seconds tends to bear out the sudden arousal of imminent collision as each "target" blossomed in size.