PPRuNe Forums - View Single Post - Mid-Air Collision over Southern Germany (merged)
Old 3rd Jul 2002, 05:34
  #178 (permalink)  
NigelOnDraft
 
Join Date: Jan 2001
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There was a comment a few pages back, from an ATCO (?) about proposed SOPs now aircraft have TCAS. It was along the lines of "get lateral separation - let TCAS sort them vertically" when aircraft are getting close.

This seems excellent advice - and would apply to us pilots also. Use the TA to try and acquire the likely "traffic" target - prepare for RA, and plan a LATERAL avoidance maneouvre if necessary. Whatever you do, when you get the RA, follow it religously, not just in direction, but 'green sector' RoC/D / attitude.

We are experiencing a "problem" (others?) with the latest TCAS software, where not all "targets" are being displayed on the screen. We have been repeatedly assured that the target not on the screen IS being monitored by TCAS, and will give TAs/RAs. Therefore visible acquisistion is not a guarantee you have the correct traffic...

Swiss ATC - it is fine to say "an error" of theirs to call the descent so late (and I agree it seems the largest factor to date) - but what are the rules? You cannot "blame" someone unless there is a limit they broke... I was reassured by the (UK?) ATCO who stated that he considered he had failed if the aircraft had not "achieved 1000' separation by 20NM". Given, for a 1000' descent an average descent rate of 500' or less, he was never going to have 1000' separation by 5NM. I really hope his intial call to the Russian was prefixed with an urgency attention getter.

Finally, although it is good advice to "keep the lights turned down" etc, I doubt it would have altered anything here vertically - even if one/both aircraft FD lights were "up". It is very difficult to judge relative altitudes by day, let alone night, and I believe there was a mid air in the USA (near NY?) (1 ac a Constellation?) where correctly separated aircraft collided because they visually felt a collision would occur, and one climbed / descended into the other (sloping cloud I think).

Lessons to me - let TCAS look after the vertical, I'll try and help laterally, and I would hope ATCOs would consider likewise when standard distances of achieving vertical separation (well before TCAS would act) have been missed...

NoD
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