TCAS or ATC
Thread Starter
Joined: Dec 2005
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From: UK
TCAS or ATC
If 2 a/c are on a collision course, and the what the TCAS is saying is conflicting what the controller is saying, what should a pilot do?
In theory TCAS should always take priority, but then again the physiological factor will kick in, a pilot will most likely obey the controller as his/her voice may be more commanding as opposed to TCAS, and surely the odds come down to 50/50, bearing in mind the other pilot of the 2nd a/c may obey controller, thus conflicting with 1st a/c.
Its easy to say that we will do one thing, but up at 35,000ft with two chunk of metals coming at each other at 550mph leaving only a few seconds, what would you do?
All a question of mind over matter......right?
In theory TCAS should always take priority, but then again the physiological factor will kick in, a pilot will most likely obey the controller as his/her voice may be more commanding as opposed to TCAS, and surely the odds come down to 50/50, bearing in mind the other pilot of the 2nd a/c may obey controller, thus conflicting with 1st a/c.
Its easy to say that we will do one thing, but up at 35,000ft with two chunk of metals coming at each other at 550mph leaving only a few seconds, what would you do?
All a question of mind over matter......right?
Joined: Apr 2004
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From: NW England
Do a search on the internet or PPRUNE about the DHL 757 inccident over Germany last year. Situtation happen where one pilot listened to TCAS and one listend to ATC.
LOL that reply by Empty cruise just made my night LOL.
LOL that reply by Empty cruise just made my night LOL.
Joined: Sep 2005
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From: Aus
Article at www.casa.gov.au/fsa/2005/aug/37-39.pdf and a small debate over said article at www.casa.gov.au/fas/2005/oct/10-12.pdf
Joined: May 1999
Aviation Qualifications: ATP+Mil
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From: Quite near 'An aerodrome somewhere in England'
On 1 Jul 2002, a Bashkirian Airlines Tu 154 and a DHL Boeing 757 are approaching each other. Both aircraft are at 36000ft due to ATC errors.
21:34:42 Both aircraft receive TAs
21:34:49 ATC instructs Tu 154 to descend to 35000ft
21:34:56 Boeing 757 issued “Descend, descend” RA. Crew responds
21:34:56 Tu 154 issued “Climb, climb” RA. Crew continues to descend
21:35:03 ATC instructs Tu 154 to increase descent rate
21:35:10 Boeing 757 issued “Increase descent” RA. Crew responds
21:35:19 Boeing 757 advises ATC they are responding to TCAS RA
21:35:24 Tu 154 issued “Increase climb” RA. Crew continues to descend
21:35:32 Both aircraft collide overhead Überlingen
Time from first TAs to collision: 50 seconds
TCAS RAs always take priority over ATC instructions!
21:34:42 Both aircraft receive TAs
21:34:49 ATC instructs Tu 154 to descend to 35000ft
21:34:56 Boeing 757 issued “Descend, descend” RA. Crew responds
21:34:56 Tu 154 issued “Climb, climb” RA. Crew continues to descend
21:35:03 ATC instructs Tu 154 to increase descent rate
21:35:10 Boeing 757 issued “Increase descent” RA. Crew responds
21:35:19 Boeing 757 advises ATC they are responding to TCAS RA
21:35:24 Tu 154 issued “Increase climb” RA. Crew continues to descend
21:35:32 Both aircraft collide overhead Überlingen
Time from first TAs to collision: 50 seconds
TCAS RAs always take priority over ATC instructions!
ECON cruise, LR cruise...
Joined: Apr 2002
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From: MIRSI hold - give or take...
Sorry if I came across a bit less than enthusiastic about your question Link4 - we generally don't bite 
However, if you use the search function for 'TCAS' and 'Uberlingen' I'm sure you'll understand how many people feel about the issue (BEagle beat me to it!)
Keep asking away - it IS a good question, and that's one of the good things about Prooning - you get a lot of questions that you never thought about yourself
The answer for this one has unfortunately already been found, and as usual, the lessons learned were paid in a lot of innocent blood 
Empty
However, if you use the search function for 'TCAS' and 'Uberlingen' I'm sure you'll understand how many people feel about the issue (BEagle beat me to it!)
Keep asking away - it IS a good question, and that's one of the good things about Prooning - you get a lot of questions that you never thought about yourself
The answer for this one has unfortunately already been found, and as usual, the lessons learned were paid in a lot of innocent blood Empty
Location, Location, Location
Joined: Oct 2003
Posts: 142
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From: If it moves, watch it like a hawk: If it doesn't, hit it with a hammer until it does...
Choice 1:
Follow system that is 'talking' to other aircraft....
Choice 2:
Follow instuctions from controller with possibly 'out-of-date' information.....
mmmmmmm.....
In case you wondered....
Make a choice other than 1:/ and, as a pilot, you should be referred for re-assessment...
Follow system that is 'talking' to other aircraft....
Choice 2:
Follow instuctions from controller with possibly 'out-of-date' information.....
mmmmmmm.....
In case you wondered....
Make a choice other than 1:/ and, as a pilot, you should be referred for re-assessment...
Last edited by mocoman; 28th December 2005 at 00:09.
Joined: May 2002
Posts: 1,704
Likes: 1
From: Who can say?
You may be a PPL and still learning, but there is no excuse for not looking around here to see if your question has already been asked and answered here.
As it is, this one has been done to death.
Follow TCAS every time. Tell ATC what you're doing. End of story.
As it is, this one has been done to death.
Follow TCAS every time. Tell ATC what you're doing. End of story.
