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Kestrel Mayday (TCAS discussion)

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Kestrel Mayday (TCAS discussion)

Old 12th Mar 2003, 10:33
  #21 (permalink)  
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I must admit I am glad to read the last replies.
Considering it was the first real "Mayday" I had to face everything went fine despite all the unseen coordinations and work we had to carry out (the pilots, controllers and everybody else involved) to solve the problem.
I certainly hope not to experience the same situation again but if I do, I hope evertyhing will work as smoothly and proffessionally as it did yesterday.
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Old 12th Mar 2003, 10:47
  #22 (permalink)  
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As an ex blip driver at LATCC for a short time, and now on line pilot, I can really appreciate what's going on as we used to do the recurrent emergency training. There's considerable activity off RT because of course the first thing that happens is to give a one to one service for the aircraft in question for a start. There is a better appreciation of the workload / stress going on in the cockpit, and the last thing is to start pressurising the pilot before he has had time to sort things out eg Kegworth.
Mayday it must always be because accidents are often a combination of 4/5 problems which can be interconnected, and although the first instance is loss of 50% power, until stablised at a FL who knows other consequential effects that may turn up. And don't forget that a bogie can wreak havok with other aircrafts planned flights. You can rehearse all you like for incidents but the reality of human behaviour can be very different when faced with crises. I was CRM instructor for a while with Airtours and had the privilege of knowing 2 captains involved in incidents. It's easy in a Sim............
Very well done to controllers and crew
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Old 12th Mar 2003, 10:53
  #23 (permalink)  
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Considering the lack of impact a PanPan has in some countries as they do not recognise at all the time I would always go for the mayday as soon as I am unable to hold altitude, period.

The best line I was ever taught was: if you have two options use the safest! Thus Mayday will always cover any doubt you might have.. (this is a 73 perspective though... 74 or A340 is differant of course)
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Old 12th Mar 2003, 10:58
  #24 (permalink)  
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I'll type slowly so that you can keep up. Some co's may need to update their SOPs as it appears that from some comments made by drivers earlier in the thread that they don't consider it a Mayday call to lose an engine and make an emergency descent. I was pointing out that maybe they need to rethink that position, for the reasons given. I sort of realise that they can't maintain height dahhh. But thanks for your input. The adults are talking at the moment. You can have a turn later.
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Old 12th Mar 2003, 11:54
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I had an engine failure on t/o out of LHR a couple of years ago. All I transmitted was "Mayday (Callsign) engine failure". ATC acknowledged and kept quiet. My colleague and I were left to carry out the drills in peace. To my lasting embarrassment I never said "thanks" to the controller afterwards.

Just because nothing is heard on the R/T, it doesn't mean nothing is happening on the aircraft, nor (I'm sure) on the ground. Quite the reverse in fact.
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Old 12th Mar 2003, 12:59
  #26 (permalink)  
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An engine failure may, or may not, be an emergency. It's not wrong to call Mayday, and it's not wrong not to. It depends on the situation. Your call, and you get paid to make that decision.

What of the MyTravel A-330 that landed single engine in ARN a few days ago? Any info on that one? Heard the crew just informed ATC they where coming in on single engine (no Mayday), and ATC made the decision to push the big button.
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Old 12th Mar 2003, 16:56
  #27 (permalink)  
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Even in a non-event like you say ManaAdaSystem, some (most) ATC agencies have further procedures themselves as directed by the overall Airport Authority. Captain calls only on one engine, no emergency, ATC have to put on a local standby at the least, possible Full Emergency so the Airport Crews are fully prepared for duty should the a/c on much reduced braking action fail to stop in time. So its not just what the aircrew perceive, we can and often do put on emergency action because we have SOP's of sorts too.
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Old 12th Mar 2003, 18:45
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<<An engine failure may, or may not, be an emergency. It's not wrong to call Mayday, and it's not wrong not to. It depends on the situation. Your call, and you get paid to make that decision>>


In fact, in the above thread, it is NOT the Engine Failure that warrants the Mayday. It is the immediate, unavoidable descent (if required). As was pointed out, Mayday implies "immediate assistance required", and ATC are unable to assist with the failed engine! They are however, able to immediately assist with the descent, and in slower time (hence maybe downgrade to PAN), with the diversion...

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Old 12th Mar 2003, 19:43
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In a very similar event in my company the other week, a PAN PAN was called with no acknowledgement, it took a MAYDAY, re-enforces the point that PAN's don't seem to be picked up on as quickly.
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Old 12th Mar 2003, 20:39
  #30 (permalink)  

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I agree with most of the above

in nats air traffic we are encouraged to go for the higher emergency state just in case as it would be easier to downgrade than update the state of emergency and is a way of covering our backs

Hence as was said sort of above you may say no emergency and find a blue flashing light at every runway exit
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Old 12th Mar 2003, 21:06
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Good stuff

very enlightening - it sometimes needs pointing out before you realise whats involved !
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Old 13th Mar 2003, 02:39
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Assuming you nice ATC chaps can't get the other traffic out of the way. If an aircraft is descending due to an engine failure, it is very unlikely that the TCAS would issue a 'climb' command during coordinated action.

If the aircraft was descending towards another aircraft the level/climbing aircraft would get a 'climb' advisory. If both aircraft were descending the most likely response from the system would be monitor vertical speed!

This should be a moot point though as in any event, aircraft SOPs dictate that the TCAS system is selected to Traffic Advisories only if the aircraft's performance is degraded. This means you would only get traffic information rather than resolution advice to enable you to decide the best way to avoid the threat.

When an engine is lost in the cruise the jet doesn't just plummet to earth, its kinetic energy is used to delay the descent for 30 secs or so whilst you decelerate to min clean. This delay should give the controllers time to clear the area or in procedural airspace the crew time to get onto a 90 away from the threats!

Hope that helps. By the way I thought you were a bit rude to 126.7. Even adults need the facts before they speak; just the other day I asked my 7 year old why she was behaving like a little girl....

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Old 13th Mar 2003, 04:27
  #33 (permalink)  
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I'm not sure I agree with some of your points there, Ghost.

The TCAS fitted to our aircraft (757/767) is not fully 'performance aware', i.e the TCAS assumes full a/c performance (at current weight ?) available at all times and is not fed any data on engine failures or shutdowns.

It is therefore perfectly possible for an aircraft on one engine to be issued a Climb RA which cannot be actioned. Thus, as you rightly point out, TCAS boxes should be selected to TA in the event of an engine failure. I also don't see why, in your scenario, the climbing/level aircraft would, de facto, be issued a Climb RA. As I'm sure you are aware, there are a complex series of interactions between two RA-enabled TCAS boxes, and the results, though always safe, are not necessarily predictable, are they ?

An RA issued simultaneously to a descending engine-out 757/A321 and a climbing ATR would, as far as I understand it, be more likely to ask the jet to climb or monitor vertical speed, as the boxes would have agreed the jet has better performance available.

With your box selected to TA, the ATR would get a more appropriate RA as the ATR system would be aware that no resolution would be issued to the jet.

Very interesting topic this, and this is only my understanding of how the kit works. Wonder if anyone knows any better !
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Old 13th Mar 2003, 09:16
  #34 (permalink)  
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Ghost, if you think all ATC need is 30 seconds to clear a safe path in this day and age, then its time to cash in your next Centre Visit ticket. Fair enough we can start the avoiding action rolling, but in a stack system?????????? Remember that avoiding the emergency a/c has EXACTLY the same priority as getting the others to still avoid each other too, even if reduced separation has to be used
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Old 13th Mar 2003, 09:49
  #35 (permalink)  
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ref 126.7 ;if he is going to treat me like a 5yo, I'll do the same for him. Honestly, it doesn't take too much effort to read the thread thru and be able to follow the discussion.

Re TCAS; I looked at as much info as I could on the subject after Bodensee, and I learned a lot. One of the most important things I learned is that a lot of the participants (pilots and ATCers) don't have a good grasp of the various systems. (not everyone agrees on whether an RA supersedes an ATC instruction- ask a Russian (and there are plenty of them flying around)). You seem to believe that you wouldn't get a climb RA when descending one engine. I believe your chances are 50/50, but I'm willing to hear any arguments . I didn't know that it's your SOP to switch to TA (but how would I?- another failing in {recurrent} atc training, knowing what sort of things are in the checklists). Is that common?
Another misconception; do you expect me to notice you in unauthorised descent? I may, or I may not (the older equipment I work on doesn't have automated alarms for things like track-keeping, altitude-keeping etc). So you better rely on your call to me to alert me to the fact. When will that call come? Not amongst the first few items I would guess. How many 000's of feet would you be down before it happened? What about the traffic 1000' below? What if you can't call immediately/get stepped on?
Lots of things to think about- not the least of which is the (yet another) TCAS issue.
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Old 13th Mar 2003, 09:59
  #36 (permalink)  
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You would be surprised how many ATCers dont know didly about a/c. Plenty dont know that a twin cant maintain cruising level with one engine out.
Its mostly due to a lack of interest and virtually no contact with the flying types. Sad but true...
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Old 13th Mar 2003, 12:01
  #37 (permalink)  
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I declared a 'MayDay' last year (flying a parachute aircraft) It wasn't a engine failure (that would have been less frightening than the situation, and I was flying a single!) Once on the gorund safely and when one has calmed down it is easy to then think a 'mayday' wasn't required. However, I reported the problem initially and had to repeat it twice without much understanding. So I declared a MayDay. The aircraft was in danger, even if not 'immediate'. I did get assistance that helped me resolve the problem but there really wasn't a lot they could actually do for me and when they said "Roger, ....., what assistance do you require?" I thought..Good question, what the hell can they do for me?"
However, without the help they gave it might have turned out a lot worse."
Thanks guys! (Lakenheath Radar!)

On the subject of the incident being discussed, I would have thought a 'pan' would suffice if the aeroplane can maintain hieght and a 'mayday' would be definetely required if it was descending regardless off what was underneath.
I don't understand why a aircraft underneath would be get a TCAS 'Climb' resolution to avoid an aircraft descending from above?
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Old 13th Mar 2003, 12:47
  #38 (permalink)  
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Nigelondraft good summary

There is an awful lot of discussion and opinions here, so I'm just doing a double check on what I've got so far.

In the event of an engine failure

1) A Mayday call is the captains call, complemented by operator SOP's

His considerations are based on

a) Annuciated effects (fire, decompression etc.)

b) Aircraft performance vs commanded thrust (ability to hold altitude)

in this case he probably didn't lose 50% of available thrust, since he is not at max performance conditions

c) Potential ATC issues affected by reduced performance

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Old 13th Mar 2003, 13:07
  #39 (permalink)  
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I suggest "MAYDAY" every time if in any doubt, then details, then "STANDBY" (very useful word, STANDBY) if all you (the pilots) want in response is brief acknowledgement and then silence.

The point I'd mainly like to emphasise here is that dealing with an ATC query is only a small part of the problem -- the biggest side effect is a break in one's train of thought and a breakdown in pilot-to-pilot communication and co-ordination. One often has to start a task all over again, or one forgets to return to the task in hand before the call, probably because another task is by then demanding one's attention. A snowball effect can soon be established, from which there is no recovery, all set in motion by an apparently simple r/t call !

The pilots are also potentially under verbal assault, to a variable degree, from cabin crew of VASTLY varying ability/common sense (IMHO). That aspect bothers me, sometimes.

It's all about workload and giving the pilots a chance of coping with it.
Old 13th Mar 2003, 13:44
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Which is precisely why when you do call, you will just get an acknowledgement. We are trained not to ask or do anything to you. We realise that your workload is now very high. Rest assured, if you're dropping straight into someone else, I will be talking. We also have a lot of things to do off R/T.

Couldn't agree more about calling it a mayday first, then downgrading if warranted. It may be that call which makes someone in another cockpit sit up and pay attention (and get out of the way/stop talking over the top of you/ etc)

Frightening, the faith people have in TCAS.
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