A few words from one who was close to it:
being an incident investigator at the unit next to Swiss Radar (we expected DHX611)and taking care of our controllers this particular night I was running a few replays of the incident. Emotions were extreme. We saw it coming, our STCA (short time conflict alert) flashed the labels in bright red 132(!) seconds before the impact. Our controllers tried to reach Zürich over all landlines they had but could not get through until it happened. This is a horrible feeling. An incident like this showed up some times before but passed as a "close shave". It´s man against machine; TCAS says acft1 climb, acft2 descend. Controller´s solution is acft1 descend, acft2 climb. Both are ok but should have the same participants. Here we had two solutions with only one participant each. DHX611 (Dilmun) performs a TCAS descent, BTC2937 (Bashkirian)has a corresponding TCAS-RA "climb" but believes the controller and descends, too.
Both acft too close and too fast to let TCAS switch the RA for the "Dilmun" into a climb. Only solution for TCAS: "increase descent". This is from 1.500fpm to 2.500fpm, normally. Such a rate is ridiculous for a TU154 being asked to "expedite descent" . Both acft hit at FL354 in the descent.
Our thoughts are with the victims and with the one survivor: the controller at Skyguide who was in charge. We consider he cannot be happy no more for the rest of his life.
What can we do to solve this "man against machine" problem?
Edited to remove text which could identify the poor soul involved ..... PPRuNe Radar
Last edited by PPRuNe Radar; 10th Jul 2002 at 09:57.