Your synopsis of the BFU's comprehensive report on the accident at Lake Constance provides reflective and philosophical food for thought. An accident chain with the most bizarre and unforeseen links in the entire history of mid-air collisions without parallel.
Consider an ATC centre without its "short term conflict alert" system and its telecommunications disabled from the adjacent centre, also the mandatory second controller required in this scenario being on a rest break.
Add a late descent issued to the Bashkirian TU-154M to be incompliance with the RVSM airway structure to continue to Barcelona. On the Tu-154M the crew comprises a captain under supervision of his co-pilot captain, a superior under a subordinate, the former giving priority to TCAS commands and the latter to the reassuring human ATC, (the final accident link solidified).
The DHL crew had the F/O, who was the PNF in the lavatory when the initial TA sounded. The captain had to assume the role of PF and PNF while complying with the RA until the F/O could reposition himself to a PNF support position, in contrast to his previous status as PF.
Further considering the Bashkirian/Russian SOPs, the last thing the DHL commander considered was that the intruding aircraft would be diving after him in contravention to a TCAS "command".
The relative "luxury" afforded the Bashkirian crew by explosive decompression, which made the long fall to earth of little consequence, is in stark contrast to the long, spiral contemplation that was dealt the DHL crew.
The positive aspect is that the Lake Constance accident was so unprecedented and unparalled that it will never achieve the banality that characterises runway incursion accidents.
David Connolly
Brussels, Belgium.
Source: Flight International
