COMM FAILURE

[fernando]

Scenario:

An aircraft is departing from Manchester to Tenerife North and the Flgiht Plan has been filled. Manchester and all surronding aiports are with OVC clouds at 800 ft. The canary islands weather is few at 1500 ft and 25ºc. (so far not a tall story)

Sometime after departure the aircraft stops transmiting, there is no way to get in contact with this aircraft, you have a real comm failure.
Their Xponder signal has also gone.

The pilots comply with the comm failure procedure.
-climbing to the cleared level
-60º turn to leave controlled aispace
-climb to the filled FL on a heading out of controlled airspace for 5 minutes
-then at filled FL joint controlled airspace.

So far, the pilots have done as expected.

But they see that the South of England is Sky clear and then the the question rises.

"Should we continue across Europe and Down to the Canary without radio or should we just land at any of those airports, say for instance Gatwick?"


What ATC expects from the pilots?


------
This situation is difficult to occur but there is a small change of happening, otherwise there will not be such much staff written down about it.
------
-----

[Snooze Vortex]

What they should do is continue to their destination! But I bet they wouldn't. Cardiff or Bristol look good for a diversion, A/c weight permitting. Why not put this on the pilots forums and see what response it generates?

It's a cracking question!

[Numpo-Nigit]

Interesting question !!!!

A few, less-than-comprehensive, thoughts -

Let's assume a filed level of FL330, a typical value I'd guess. OK, the aircraft was cleared to FL190 and then goes RTF. Turn to leave Alpha two-five at that level and then climb outside CAS to filed level. As all airspace above FL245 is effectively a controlled environment, how can this be done?

Having lost the transponder as well, nobody will know what is happening. Following recent policy decisions to progressively remove primary radar cover from "less busy" areas of the UK, the chances are that this aircraft will not be visible to LATCC anywhere south of the Brecon area. So, combining the loss of R/T, loss of transponder, sudden 60 degree turn, and then loss of primary contact - the likelihood is that we'll be assuming "the worst" and Plymouth RCC will be getting involved.

As for the idea of diverting to a southern UK airport in these circumstances. Bristol, Cardiff, Filton, Exeter, St Mawgan - perhaps, with extreme care. Gatwick, or any other LTMA airfield - no way !!!!!

Discussions of what a pilot will or will not do in the event of RTF are always a good bet for a quiet moment ( remember those? ), but when it actually happens - anything goes!!!

[fernando]

snooze, in VMC, they should follow ICAO procedure. As this is the presented case.

they should do:
-continue on VMC, (which is not VFR)
-land at the NEAREST SUITABLE aerodrome
-report their arrival

Please administrator , do move/copy this post if you think it is required.

I think it is a very rare and serious emergency, and as NUMPO says "anything will do in a real emergency". but it will help if have some clues on where might they be flying to, not just to give them a green light to land.

[Bagheera]

Get out your mobile phone ,make sure P1 has got a fim grip of controls, phone previously saved area centre phone number,scream at operator to put you through to sector,ask them what you should do! :)
We have this technology why stick to the old rules. Imagine an aircraft just south of MCT, for example, turning L/R 60 degrees on a busy northabout day. :eek:

[fernando]

Are mobile phones within range above 33000 ft?
Will it be possible to make a phone call?

I do think some rules are up to date and diffcult to follow (if not impossible) but ... (keyboard aint transmitting)

[Sick Squid]

Interesting point, particularly the bit about leaving controlled airspace to make the climb (assuming a "Request level change en-route" clearance.) Not the easiest thing to achieve in the UK, certainly out of the major South East airports.

What will be going on in the cockpit is some of the above plus the following: an awful lot of frantic referring to the extremely complex chapter in the AERAD Europe and Middle East Guide, both as a refresher on the ICAO basic procedure, and any specific procedures for the aerodrome if aplicable, but also the unbelievably complicated table of scenarios under United Kingdom rules. The relevant Aerad (Sorry, Racal or Thales or whoever it is this week) charts would also be being pulled out from the morass in our chart book. All this whilst bearing in mind the first part of the Aviate, Navigate, Communicate Triumvirate..... TCAS would become our single best friend for a while as well.

Now once we had sorted out what we were going to do in accordance with all of that, and having given in to the fact that we will undoubtedly get "something" wrong that we will be bollocked over later, I can tell you that I for one would not, repeat not, nay never do a dirty dive from 35,000 to a suitable airport just because I could maintain VMC, without other overriding circumstances. We are on an IFR flight plan after all, in controlled airspace and I firmly believe that the VMC curve-ball exists for those aircraft who lose contact on climbout and can continue in the circuit to land at a suitably quiet airport or piece of airspace.

In your scenario above, I'd squawk 76, and continue as-per the ICAO basic procedure towards TFS, including the procedural approach from altitude descending in the hold... the controllers there would have had plenty of heads-up time, and would be expecting that from us.

However, what if you get a failure inbound LHR from the north, filed on a BNN 1A? ICAO says, hit BNN at altitude at c.ETA, then descend to land in 30 minutes. As an LHR based pilot, I would do the following, on a 76 squawk... descend in accordance with the published restrictions on the STAR, hit BNN at the last restricted altitude, hold for a minimum of ten minutes whilst descending to lowest stack level, then approach proceduraly... (I'm writing from memory, here, this would of course be modified by a frantic read of the book.)

I might be wrong in certain aspects of this, but it is such a grey area... one which I was running over in my head just this very evening....

Thoughts? Sorry for the disjointed nature of the post, but it is an accurate reflection of the disjointed thought process that accompanies any discussion or application of Radio failure in controlled, and busy airspace. The real world and the books seldom tie up and I suspect there would be a lot of second guessing going on.

£6

[ 04 August 2001: Message edited by: Sick Squid ]

[davebuckley]

:confused:
1) Don't all commercial aircraft carry dual comms and dual transponders.

From a safety analysis point of view, i believe that dual UNRELATED failures are not considered.

Ultimately, is that not what pilots are there for. In an extremely unusual situation a human can plan, carry out the plan, and then modify the plan as necessary, which computers cant do (yet).

---------------------------------------------
"If the coffee is in your lap, roll through 180 degrees"

[Ondrej]

During training we've been told that failure of both radios is very unlikely, and if it happens, you just have to WATCH the screen, and act accordingly, MOVE TRAFFIC OUT OF that deaf guy's WAY, whatever he is trying to do. But we expect him to proceed according to fpl, maintain last cleared speed and level for 5 minutes, then climb to planned level, hold over the beacon serving the destination field....and so on...
BTW....in case both transponders goes off as well..... that makes a situation... you cant see his level, you cant see 7600, and in some centres you even cannot see a primary response.... AND, of course, if he is not squawking, other aircraft WILL NOT SEE him on TCAS, so Resolution advisory will not be issued..... all you can do is to sit and watch....8-)

[ 04 August 2001: Message edited by: Ondrej ]

[Sick Squid]

Hang on, RT'ing the F'in Q again.... a dual failure is highly unlikely, and would in general be down to a total electrical failure with an additional failure of Transponder 1 and VHF 1 at the same time... in which case comms problems would be rather low on my list of priorities. Then VMC to nearest suitable from altitude would become a probable option. Normally, dispatch with one of the 2 Txpndr systems is allowed (if at all) only if it is NOT the system which will remain when the aircraft is on battery power only; usually anything beginning with "1."

So re-reading the scenario above, even allowing for a lower-order freak five system failure (3x VHF, 2x ATC Txpndr and a bonus of 2x HF if fitted..) I have the distinct impression that certain other agencies might take a close interest in the progress of the flight, and the "Interception Procedures and Signals" page would be frantically reveiwed. I'd certainly welcome the attention...

Anyway, what is the International Signal for "Hang on 10 seconds whilst I get the book out?" ;)

£6

[ 04 August 2001: Message edited by: Sick Squid ]

[Sniff]

Sure a Homer Simpson face mask would suffice...... :)

[Numpo-Nigit]

Possibly a silly question, but...

Assume it is not a TOTAL electrical failure, however all transponders have failed. Will the TCAS still work on "receive" or is it so closely connected to the transponder that it will fail also? I realise that other aircraft TCAS will not "see" you, but will you still be able to "see" them?

[fernando]

thanks to all for your opinions.

If you have a transponder failure TCAS is gone. and if you have a complete comm failure, it is most likely that you have to deal with an even more serious emergency than the VHF,(anyway, it is always nice to tell somebody what you are doing.)

Having a complete comm failure is rare to occur, but ICAO has specified some rules about this emergency and many countries have adopted them but with some differences. the uk comm failure procedures are complex and some times questionable (as somedoby said: above FL 245¿? all the sky is controlled).

I think there arent many "suitable aerodromes" in the south of england for that type of emergency and probably the most suitable is your destitation. (this is my point of view) just imagine your are at the aerodrome tower ANYWHERE and you spot an aircraft on final, What atc will do shout louder in the mic wont do much good. obviously all ATC centers will have been alerted, ¿ALL?

But again, I will like to know what will you do.
will a pilot wander across europe without a "say again frequency"?
will ATC across europe will be pleased to have a pilot (most likely 2 of them) without a clue of where they are, doing and going?


It might all be too confusing, in that case dont worry about it, the chances of happening are very, very little.
But, in that case why publish all those procedures?

gracias a tod@s

[HugMonster]

With double VHF failure and TXPDR failed as well, we have no TCAS, and we are likely to have lost almost everything electric. If anyone thinks I am going all the way to TFS with no coffee machine working (s0d the radios) they have another think coming. I ain't gonna climb to filed level at all. I shall do what I can to clear controlled airspace, proceed VFR to wherever I can get in, or IFR back where I started. You guys can get everything else out of my way, or send a shepherd, or whatever you like, and sorry about the hassle, but, if you can't take a joke you shouldn't have joined! :)

[Rad1]

Going back to the point that MDS made, although most aircraft carry dual comms this does not mean that RT failure won't happen.

Whilst training another controller some years ago (but not that many!) I posed the question of my u/t if an inbound aircraft that we were watching but not yet working went RT fail - what would he expect it to do?
My u/t effectively declined to answer claiming that aircraft carry so much redundancy that it just won't happen. It was only meant as a discussion point to chat about the possible options - I didn't have a definitive answer.

Strangely, before the week was out, an inbound aircraft (a BA11, admittedly in corporate configuration but, presumably, with a similar fit to many aircraft flying around with cattle class seating) stopped talking to anyone. The first indication was when airways called to ask if we were talking to it as it was coming up to the usual handover point and they could get no response. The aircraft eventually called as it approached the overhead using a handheld radio that one of the crew carried in his bag.

The problem - a cup of coffee knocked over the comms stack.

Sadly my u/t wasn't there to eat his words.

In practice I did as Ondrej says, kept everything else out of the way and watched carefully. Chatting to the crew afterwards, I recall they were trying to follow the R/T fail procedure (but having trouble confirming that it was the 'right' one) and were uncomfortable doing so but grateful that it was generally VMC.

It brought it home that, even these days, RT failure can still happen.