TCAS vs. ATC: who takes priority?
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TCAS vs. ATC: who takes priority?
Hey again, still feeling inquisitive 
I'm sure that there's probably one definite answer for this in the ol' Pilot's textbook, but I was just curious about it:
When it comes to traffic avoidance, who takes priority, ATC or TCAS?
If ATC says, "Callsign 1234, alert, traffic, cease ascent!"
...and the TCAS says, "Traffic, traffic, climb!"
...what must the PF do? I imagine this must be incredibly disorienting. I know I wouldn't like to be the PF in one of these situations!
Thanking you for any insight
I'm sure that there's probably one definite answer for this in the ol' Pilot's textbook, but I was just curious about it:
When it comes to traffic avoidance, who takes priority, ATC or TCAS?
If ATC says, "Callsign 1234, alert, traffic, cease ascent!"
...and the TCAS says, "Traffic, traffic, climb!"
...what must the PF do? I imagine this must be incredibly disorienting. I know I wouldn't like to be the PF in one of these situations!
Thanking you for any insight
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As PT6 says, comply with the TCAS. This is what can happen in circumstances where you don't Bashkirian Airlines Flight 2937 - Wikipedia, the free encyclopedia
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TCAS RA's ALWAYS......
Euro control have some info about TCAS here:
http://www.eurocontrol.int/ra-downli...%2022Nov07.pdf
Euro control have some info about TCAS here:
http://www.eurocontrol.int/ra-downli...%2022Nov07.pdf
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Follow TCAS and declare "TCAS RA" to ATC, they stop transmissions/clearences up to your "Clear of conflict, resume .......".
That's in Euroland, guess somewhere else still using "TCAS Climb/Descent".
FB
That's in Euroland, guess somewhere else still using "TCAS Climb/Descent".
FB
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Follow TCAS for vertical, and ATC for headings
Never turn when TCAS is issuing instructions. The TCAS software solution is based on 'wings level' and commanding rate of climb or descent.
Turn during an RA or TA and you throw your protection out the window.
"Traffic" or RA? Follow instructions. Don't turn. RA trumps ATC. Advise ATC iaw local AIP.
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ITCZ,
Hmmm, only just considered that scenario. So, if you're in a turn and get an RA, the automatics come out and you follow the RA command while rolling wings level?
Genuine question - I probably should have considered it before but RAs always seem to come when S+L in the sim.
Have you got a reference for a description of the wings-level software solution?
Cheers,
B&S
Hmmm, only just considered that scenario. So, if you're in a turn and get an RA, the automatics come out and you follow the RA command while rolling wings level?
Genuine question - I probably should have considered it before but RAs always seem to come when S+L in the sim.
Have you got a reference for a description of the wings-level software solution?
Cheers,
B&S
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Our ops states: If a TCAS RA and ATC controller's breakout instructions occur simultaneously, comply with the TCAS vertical guidance and follow the controller's turn/heading instructions.
For goodness sake!
This has been covered so many times!
TCAS is followed as the highest priority. Controllers know this and flight crews know this. Surely there is no longer anyone in any doubt?
Last time someone got this wrong people died.
This has been covered so many times!
TCAS is followed as the highest priority. Controllers know this and flight crews know this. Surely there is no longer anyone in any doubt?
Last time someone got this wrong people died.
I got an RA recently, called "ABC 1234 TCAS climb" and ATC came back with "negative maintain niner thousand".......hard to believe I know but that was the response. I just said "negative abc1234 TCAS climb"
So it does happen where they put you in that position of deciding.Full report followed of course.
So it does happen where they put you in that position of deciding.Full report followed of course.
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If I misheard "ABC 1234 TCAS climb" as "ABC 1237 request climb" (and I think that could be most easily done), I would come back with "negative maintain niner thousand"... if I believed there was traffic above. Aust AIP says "TCAS RA..." which I have heard a couple of times (both false alarms obviously, I'm still in the business) and really got my attention.
If an ATC has still not yet grasped the situation, the pilot is supposed to respond to any such instructions with "UNABLE TO COMPLY, TCAS RA (thinks: f%$#wit...)", or something like that.
Sounds like a dumb idea. On the other hand, if I have compromised separation and think the TCAS is possible RA'ing as I speak, (heaven forfend), I would issue an alert and a suggested heading and not screw around with the levels. I would leave the levels to the TCAS.
If nothing else that should tell the crews that the guys on the ground have bolloxed it up and trust your technology
If an ATC has still not yet grasped the situation, the pilot is supposed to respond to any such instructions with "UNABLE TO COMPLY, TCAS RA (thinks: f%$#wit...)", or something like that.
Follow TCAS for vertical, and ATC for headings
If nothing else that should tell the crews that the guys on the ground have bolloxed it up and trust your technology
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TCAS RA in a TURN???
I know the instruction must be followed over ATC instructions but my issue is whether you can continue the turn or must level the wings first and then Climb/Descend.
ITCZ you state that "Never turn when TCAS is issuing instructions. The TCAS software solution is based on 'wings level' and commanding rate of climb or descent. Turn during an RA or TA and you throw your protection out the window."
My Operations Manual clearly states:
"If an RA is given in a turn, the turn may be continued"
Can someone please clarify the action required (regarding roll) with a TCAS RA in a TURN please?
AkA.
ITCZ you state that "Never turn when TCAS is issuing instructions. The TCAS software solution is based on 'wings level' and commanding rate of climb or descent. Turn during an RA or TA and you throw your protection out the window."
My Operations Manual clearly states:
"If an RA is given in a turn, the turn may be continued"
Can someone please clarify the action required (regarding roll) with a TCAS RA in a TURN please?
AkA.
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A TCAS RA always has priority, but not a TA. The RA virtually eliminates human ATC or pilot error. Just be mindful of aircraft that are not operating mode c transponders, or formation flights where only one aircraft has a transponder turned on (rare, but it happened to me once).
Be sure to send in the required operations report, which should alleviate any record of wrongdoing by the pilot.
Cretan
Be sure to send in the required operations report, which should alleviate any record of wrongdoing by the pilot.
Cretan
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The bigger problem is that TCAS may solve an issue by issuing a climb and putting the aircraft at risk against a preceding higher traffic.
My suggestion has been to receive direct feedback of TCAS displays on the ATC radar console, particularly in approach, so the controller knows real time what instructions are being displayed to the pilots.
My suggestion has been to receive direct feedback of TCAS displays on the ATC radar console, particularly in approach, so the controller knows real time what instructions are being displayed to the pilots.
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TCAS is capable of giving an RA for multiple aircraft threats. It avoids putting you into another RA, but if it does, it will give the appropriate guidance. This is why you want to keep the RA vertical guidance in your scan during an RA, as it can change dramatically.
All of this is, of course, assuming that all target aircraft are equipped with at least a mode c transponder.
Cretan
All of this is, of course, assuming that all target aircraft are equipped with at least a mode c transponder.
Cretan
If I misheard "ABC 1234 TCAS climb" as "ABC 1237 request climb" (and I think that could be most easily done), I would come back with "negative maintain niner thousand"...
Iceman,
That is specifically and only tp do with breakout instructions during a PRM ILS procedure. In all other cases, RA should be complied with with wings level.
HOWEVER, the response to a TA is "Manoeuvre as required". There is no TCAS instruction with a TA, and no limitation on lateral manoeuvring. Rules of the air still state that aircraft on a collision course should alter heading to the right, so I think a turn to AVOID an RA situation is an appropriate response.
That is specifically and only tp do with breakout instructions during a PRM ILS procedure. In all other cases, RA should be complied with with wings level.
HOWEVER, the response to a TA is "Manoeuvre as required". There is no TCAS instruction with a TA, and no limitation on lateral manoeuvring. Rules of the air still state that aircraft on a collision course should alter heading to the right, so I think a turn to AVOID an RA situation is an appropriate response.