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Crew ignored TCAS RA

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Crew ignored TCAS RA

Old 12th Nov 2016, 07:33
  #121 (permalink)  
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Basil :
I wonder what additional protections the AirBus system has to avoid the situation mentioned by Aerocar?
T
The partial answer was in Aerocar message :
our RADALT was sending bad info
Question is : is this a regular event or 1 in the minus 6 , or a more Boeing problem? ( e.g. TK1951 in AMS)
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Old 12th Nov 2016, 08:47
  #122 (permalink)  
 
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It was a Dash 8. It was several years ago that it happened, but I think the radalt wasn't sending any info at all to the TCAS so the TCAS low level inhibits weren't active. I don't know enough about that specific system to know how likely it is to happen again. Airline pilots fly with stick pushers that are also capable of pushing the nose towards the deck at low level but a bit of fail safe engineering makes that very unlikely. We have five seconds to respond to an RA, if a fully automated system announced the RA then paused for a couple of seconds prior to flying the manoeuvre then we'd have a reasonable chance of disconnecting the autopilot in time to prevent an unsafe RA.
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Old 12th Nov 2016, 08:56
  #123 (permalink)  
 
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It seems to me that those advocating not following an RA are extracting the one caveat from the regs/docs that suits them, without understanding, or choosing not to understand, the full document or operation of TCAS.
Maybe training and understanding of TCAS is deficient in their organisations?

Yes, the PIC has the option not to follow an RA, just as the PIC has the option to not follow other warnings and best practices, if in their judgement, it is safer to do so.

But TCAS is collaborative. It functions based on the actions that two or more aircraft crews are going to take to resolve a conflict.
If one crew is only ever going to assess the situation and choose by themselves what to do, then surely the correct mode for that crew to operate in is

TA-only ?

In this way, any other aircraft in the scenario will have RAs that take into account this response.
The same mode as when you are engaged in an emergency descent, an engine out, or the mode that should be automatic in certain parts of the flight, such as close to terrain (unless the system has a problem)

BTW. In case of any pedants reading this, I am not advocating to operate in TA mode only.

Surely the training should be- Follow the RA. It's a really easy manouver, which takes a couple of minutes to train in the sim, unless you are ham fisted. In which case ask for a little more time to train in this complex manouver.
Your situational awareness cannot take into account what actions those many other aircraft around you are taking, until they have clearly taken it.

Last edited by Lancelot de boyles; 13th Nov 2016 at 07:14.
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Old 12th Nov 2016, 11:04
  #124 (permalink)  
 
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I wonder what additional protections the AirBus system has to avoid the situation mentioned by Aerocar?
I believe even the Airbus has an autopilot disconnect button?
What do you do if you do an autoland and the aircraft misbehaves (if you are not a SQ pilot, that is)?
All automatic systems can fail.
I suspect Airbus automated the TCAS because we, even after what we have learned, what we have trained and after a number of people got killed, still have pilots out there who think they know better.
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Old 12th Nov 2016, 11:36
  #125 (permalink)  
 
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Correct MAS. The A380 automated TCAS / RA response feature from the operational perspective prescribes a rigid FMA adherance. In the unlikely event that the automation does not work there is a back up sop to fly the manoeuvre manually. The automation is incorporated in both f/d and a/p modes. Whether you are flying a fully automated A380 /A350 or a less sophisticated aircraft you must follow the RA even @ aircraft certified ceiling. Regardless of 'taking a chill pill' any alternative is ill - informed drivel. As I stated before, any professional pilot on this site who thinks differently why not 'debate' the point with your TRE on your next LPC.
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Old 12th Nov 2016, 19:20
  #126 (permalink)  
 
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I think what that F16 pilot fails to understand is the consequence of his actions on the other aircraft and it's passengers.

He has already caused an unnecessary RA to a passenger carrying aircraft which resulted in injury and still hasn't learned.

What he also doesn't understand is that passenger carrying airliners have more than one pilot. If the pilot flying decides to ignore an RA, how does he/she confer with the other pilot on the flight deck that they are doing so to "increase safety" (unless it's obvious or SOP such as below 1000' RA).

The only way to defend ignoring an RA is that if following it would have jeopardised the safety of the aircraft. In F16's examples, that is clearly not the case.
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Old 12th Nov 2016, 22:38
  #127 (permalink)  
 
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Couldn't agree more TangoAlphad

Some single seat pilots find the transfer to a twin pilot world terribly difficult!

The lack of psychic abilities in their co-workers must be enormously frustrating!
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Old 13th Nov 2016, 08:17
  #128 (permalink)  
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ICAO DOC 8168 - Aircraft Operations:

"in
the event of an RA, pilots shall:
1) respond immediately by following the RA as indicated, unless doing so would jeopardize the safety of the aeroplane;
Note 1.— Stall warning, wind shear, and ground proximity warning system alerts have precedence over ACAS.
Note 2.— Visually acquired traffic may not be the same traffic causing an RA. Visual perception of an encounter may be misleading, particularly at night.
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Old 13th Nov 2016, 08:56
  #129 (permalink)  
 
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Already quoted in post #97.
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Old 13th Nov 2016, 10:35
  #130 (permalink)  
 
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Note 2.— Visually acquired traffic may not be the same traffic causing an RA. Visual perception of an encounter may be misleading, particularly at night
As I recall it there was an old adage in the fighter world along the lines of "It's the one you don't see that gets you..."

Might still be worth bearing in mind..................
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Old 13th Nov 2016, 10:43
  #131 (permalink)  
 
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Not wishing to support ignoring an RA, but: F16Guy is in an a/c with vast spectrum of electronics sensors, displays of a swarm of bees (friendly), a large + & - g capability and a bubble canopy. The ability to see & avoid is different for them than us. Should they receive a "descend now.. increase rate" RA he could roll & pull in the wink of an eye. What he would then do on the subsequent RA from traffic 10,000' below would be interesting. He might also have the option to manoeuvre laterally, which we do not yet have.
Either way it's not apples & apples. I expect the military have more flexible SOP's than us.
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Old 13th Nov 2016, 11:27
  #132 (permalink)  

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Guys. We've got to post 140 on this, and are still disputing it. FOLLOW THE RA. End of story, and rant.
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Old 13th Nov 2016, 11:37
  #133 (permalink)  
 
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Yes, once again these rules have been written in blood and are there for a reason.
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Old 13th Nov 2016, 16:41
  #134 (permalink)  
 
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Reading this thread has just scared the cr@p out of me.
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Old 13th Nov 2016, 16:57
  #135 (permalink)  
 
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End of story
No, it's not. You fly into busy,one way in, same way out mountain airports and needlessly follow the RA on the aircraft you've seen for the past couple of miles, you're asking for trouble. Could you be seeing another aircraft, yes but the chances are greater the RA will introduce a threat than resolving one. This especially so when both are talking to the tower in Class D airspace. I've been in the situation where id have been put into a precarious position had I followed the RA, the other guy (which I've been on many an occasion) is now placed into a position of having to fly an emergency terrain extraction needlessly at places like KASE.

Few rules or conventions is so universal that you can say something is an absolute or "end of story" to use your words.
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Old 13th Nov 2016, 18:37
  #136 (permalink)  
 
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I hope this matter can be now put to bed, but.....anecdotes are just fun, sometimes. I was subject to the JFK guys 'pushing tin'. Approaching finals, No.5-ish, at 90 degrees and 210kts. I was asked to go to 230kts to slot in and establish on LOC. ATC never stopped talking. I was then given 'clearance to land'. (don't go there; it's been discussed at length). Meanwhile I can hear the guy behind me being asked to slow to 180kts - I assume to stretch it out behind me, a heavy. Meanwhile I'm still steaming in at 230kts and visual with all a/c ahead of me & the runway. I'm trying to get a word in & request to slow down to get flaps etc. out for landing. No chance. Johnny Carson on ATC is in full flow. I now get a TA on the a/c in front. He's slowing down. Soon that is going to evolve into an RA. Then what? That is going to be a climb, I hope, but I'm still at 12-15nm on the glide. I'm watching the range decrease, and, just before I start to get real twitchy, ATC give me 90 degrees right, 180 left, 90 right and I'm still No.5. No doubt there was an 'oops' moment in the radar pit. However, I always wonder what would have been the outcome if TA had become RA. There was no chance of collision; it was a closing speed thing and all I had to do was slow down; I had penetrated the bubble on the guy in front; except I was under ATC command. If I'd slowed down to maintain separation at the limit of the bubble it would have domino'd down finals behind me. So what, but under ATC we are 'trained' to follow orders.
It all worked out, but an interesting encounter of the 3rd kind.
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Old 13th Nov 2016, 20:38
  #137 (permalink)  
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RAT5 :
There was no chance of collision
Then you will never get an RA.
The collision geographical model is very complex ,not many people really understand it 100% ( me included) but when TCAS works normally, you need to be on collision course to get an RA. In your JFK case, if you follow someone slightly slower it will just be a long TA...until you get very close of course, or below 1000ft AGL.
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Old 13th Nov 2016, 20:55
  #138 (permalink)  
 
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There are many fools flying after reading this thread.
ALWAYS FOLLOW RA'S
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Old 14th Nov 2016, 08:06
  #139 (permalink)  
 
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I think the most important point, which keeps being stressed then ignored, is that THE RA MAY NOT BE CAUSED BY THE AIRCRAFT YOU CAN SEE.

In RAT 5’s example above, it would have been easy to fixate on the aircraft in front (not implying you were, RAT 5) especially if you were already getting a TA. When it turns into an RA it could be another aircraft attacking from the side that you weren’t previously aware of. I actually had this exact scenario happen at JFK on long final and it was VFR traffic that wasn’t talking to Kennedy...
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Old 14th Nov 2016, 08:16
  #140 (permalink)  
 
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Forgive my ignorance but my training has always taught me that TCAS RAs MUST be complied with.
Now skygods, I´m only a lowly Citation driver - I have been taught exactly this:

follow the RA.

HAVE I BEEN LIED TO ?

Yes or No, please.
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