Egpws/tcas
Thread Starter
Joined: Jul 2007
Posts: 21
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From: FL280 and below
Egpws/tcas
Hello guys,
Iam not sure if this has been discussed before, so I am starting new thread.
We were departing an airport in austria followed by an early right turn over mountaineous area with an MSA of 8600ft, in the climb I observed a target on the TCAS approx. 1500ft above, 8NM away with a high rate of descent (separation was safe). The question now:
Is it possible to get an TCAS RA "Descent" followed by an EGPWS warning "TERRAIN Pull up" a few seconds later?? I am not sure if both systems are communicating with each other?! Are there any procedures for a case like that??
I asked two of our TREs, but they were not sure either.
Thanks for your help!!
speed alive
Iam not sure if this has been discussed before, so I am starting new thread.
We were departing an airport in austria followed by an early right turn over mountaineous area with an MSA of 8600ft, in the climb I observed a target on the TCAS approx. 1500ft above, 8NM away with a high rate of descent (separation was safe). The question now:
Is it possible to get an TCAS RA "Descent" followed by an EGPWS warning "TERRAIN Pull up" a few seconds later?? I am not sure if both systems are communicating with each other?! Are there any procedures for a case like that??
I asked two of our TREs, but they were not sure either.
Thanks for your help!!
speed alive
Joined: Sep 1998
Posts: 1,615
Likes: 1
From: wherever
Might be different depending on type but I would say yes. TCAS descents are inhibited below certain heights but if your high enough theres no other reason as TCAS and EGPWS don't talk to each other. I know which one I would follow as apart from a sudden earth quake theres not much chance of the mountain avoiding you where as the other aircraft could.
Joined: Jul 2000
Posts: 91
Likes: 0
From: Germany
Usually (E)GPWS-Warnings have the highest priority of all aural warnings and thus will supercede TCAS-TAs/RAs.
We had a set-up in the SIM where you are level flight, quite low altitude (~ 2.200 AGL). An intruder descending from above sent us into a TCAS-descent. The fixed TCAS-descent-rate of 1.500 fpm lead to a (E)PGWS-Warning shortly after establishing the descent.
After some brainstorming it makes sense to me in so far as there's a chance you miss the other traffic while you would hit the ground for sure.
Regards, MAX
We had a set-up in the SIM where you are level flight, quite low altitude (~ 2.200 AGL). An intruder descending from above sent us into a TCAS-descent. The fixed TCAS-descent-rate of 1.500 fpm lead to a (E)PGWS-Warning shortly after establishing the descent.
After some brainstorming it makes sense to me in so far as there's a chance you miss the other traffic while you would hit the ground for sure.
Regards, MAX
Joined: Mar 2006
Posts: 1,115
Likes: 86
From: England
I do not wish to be patronizing, but a search of the forum would have found an answer;- the major warning systems have a system of priorities, as above. They may not ‘talk’ to each other, but the warning output is regulated to maximize safety.
An issue of greater concern is that several pilots do not know, or fail to recall, basic training aspects of this technical logic. This weakness might delay a pilot’s reaction in the event of a warning – a hazardous attitude – I know better, or let’s do it this way (because I am reconsidering it – an opportunity for error). These high priority warnings are some of the few which require action without thought.
I do not wish to focus on the individuals, especially those who ask questions. These have a positive attitude; self recognition that something is not known is a valuable skill.
What needs to be understood is why such information is not known. Has someone decided not to teach it (it’s not important), or has the subject been taught in such a way that memory recall is difficult?
Taking a wider view of possible deficiencies in technical knowledge, similarities might be found in most accidents discussed this year, which have involved the pilot–aircraft interface.
Has the industry something to learn?
An issue of greater concern is that several pilots do not know, or fail to recall, basic training aspects of this technical logic. This weakness might delay a pilot’s reaction in the event of a warning – a hazardous attitude – I know better, or let’s do it this way (because I am reconsidering it – an opportunity for error). These high priority warnings are some of the few which require action without thought.
I do not wish to focus on the individuals, especially those who ask questions. These have a positive attitude; self recognition that something is not known is a valuable skill.
What needs to be understood is why such information is not known. Has someone decided not to teach it (it’s not important), or has the subject been taught in such a way that memory recall is difficult?
Taking a wider view of possible deficiencies in technical knowledge, similarities might be found in most accidents discussed this year, which have involved the pilot–aircraft interface.
Has the industry something to learn?
Joined: Nov 2008
Posts: 22
Likes: 0
From: USA
EGPWS has an output when it is in an alert condition (caution/warning) that is connected to TCAS inhibit input. So if EGPWS is alerting, TCAS cannot alert until EGPWS alert has completed. But it certainly is possible (as said earlier) to get a TCAS alert followed by and EGPWS alert, or to have EGPWS alert interrupt a TCAS alert.
