Emergency Descent, 90 degree turn?

[Spodman]

I've just done an training module where it was claimed that the first thing (after putting on. . the oxygen mask) a pilot will do is turn 90 degrees off track (unless in a holding pattern). . .. .I was aghast I could play in this wonderful industry for this long without knowing this, but it seems a bit unlikely. Can anybody confirm this procedure?. . . . <small>[ 16 March 2002, 00:03: Message edited by: Spodman ]</small>

[106027]

There is a bit more to this than that. It would be wiser to instruct to turn into the most favorable direction. On top of that, with TCAS, we have the possibility to see other possibly conflicting traffic.

[yxcapt]

I've seen many different types of procedures for the emergency descent. Two reasons for the turn include getting off the airway or track, and/or to keep a positive 'G' load on the airplane during the initial push over.

[pigboat]

The generic way is to roll the aircraft either right or left to forty five degrees of bank, all the while reducing power and operating the speed brakes/lift dump. Allow the nose fall through the horizon to about twenty degrees or so nose down, level the wings and let the airspeed to build to MMO/VMO. As yxcapt says, the roll will apply positive G and turn you off the airway. If you suspect structural damage to have occurred, you may want to carry out the descent in a high drag/low airspeed configuration. In that case in addition to speed brakes add the gear and flaps and instead of MMO/VMO descend at the maximum IAS for the configuration.. .Different aircraft types no doubt have different procedures, but with minor variations the above one is pretty general.. . . . <small>[ 16 March 2002, 05:02: Message edited by: pigboat ]</small>

[BOAC]

A well-established procedure. Far less likely to hit something on the way down when you are outside the airway than in it with levels below you allocated?

[Pegasus77]

It most often is not SOP, but merely airmanship. No one would sink through many flightlevels in a congested airway. Only country I know of where it is mandatory to turn off the airway, is Russia, where you have to make a 30deg turn to your right.

[NorthernSky]

Practically, the best thing to do (in a radar environment), is to make your RTF call:. .. .'Pan Pan Pan, London Control, Bloggsways 123, emergency descent, descending FL100, we can fly radar headings'.. .. .This will enable the controller to shift you away from the thirty aircraft under you, rather than the thirty aircraft away from under where you're going. Especially important where those aircraft are under control of another sector.. .. .Also, in an SSR environment, squawking 7700 will 'force' your datablock through onto the displays of the controllers working airspace under you, who have height filters on to display only their traffic (and a bit more, vertically speaking), thus enabling them to see you coming before you plummet into 'their bit' (technical ATC term) at 6000fpm plus.. .. .Perhaps a couple of current ATCOs could back this up and add to (or even subtract from) it? (eyeinthesky, where are you when I need you?). . . . <small>[ 16 March 2002, 23:08: Message edited by: NorthernSky ]</small>

[Checkboard]

It's one of those things you can use to amuse your mind as you fly along on autopilot. Just as in light singles, you may have looked out of the window to spot suitable forced landing sites, in an airliner you think about safe directions to fly should you have to perform an emergency descent, along with the drift down altitude you will require in the event of an engine failure.

[BOAC]

Northern Sky - thank you for your input - worth progressing and perhaps it needs reviewing. The only caveat I would place here is that we (flight crew) have to think about operating in many FIRs, not just UK, and without being unkind... well...........

[NorthernSky]

BOAC,. .. .Quite right. When flying into unfamiliar FIRs, I review the appropriate procedures coming up to the boundary, and have the charts to hand.. .. .A couple of points: First, be wary of making that turn to clear the airway if it will take you into a danger area or military training area or what-have-you, second, I would think that in a busy CTA (Daventry, for example), a ninety degree turn without instruction to do so could put you well and truly in the brown stuff.

[BOEINGBOY1]

this is standard procedure when flying nat-track routings if you require rapid decent. due to the absence of radar this procedure instantly seperates you from all other traffic.

[Young Paul]

I think in either RVSM or MNPS, the turn off track is mandatory. Can somebody shed light on this?. .. .As for the "generic" emergency descent, it certainly isn't the specific one for B737 or A320. Furthermore, if structural failure is suspected, speedbrake and acceleration are discouraged as well.

[Fresca]

The airspace over the N-Atlantic is RVSM, so it is both MNPS and RVSM. As most planes crossing the Atlantic fly the precribed tracks (A,B,C,D and so forth) and the tracks are seperated by 60 NM laterally and 1000' seperation vertically on a same track it is recomended to turn of the track during emergency descent and the fly offset by 30 NM. This should keep the troubled aircraft away from other traffic as there is no radar coverage over most of the N-Atlantic (except from the Faroe Islands, Iceland and Greenland).

[DontSink]

I`ve nerver been told to turn while starting descent unless you`re in NAT airspace, turn 90º and offset by 30 NM. . .. .But over europe in our sims we`ve always been told, not to turn unless instruted by ATC to do so, and you can indeed turn without letting ATC know, in case you know there is traffic bellow, or congested airway and no other airway or traffic to the side, weel... GOOD CAPTAIN JUDGMENT!!! <img border="0" title="" alt="[Roll Eyes]" src="rolleyes.gif" /> But first have a look to the TCAS and see the traffic and have a tought about the terrain, look to the charts or enquire ATC. . .. .Turning while putting the oxygen masks on, <img border="0" title="" alt="[Confused]" src="confused.gif" /> is against safety. Acording to the Boeing FCTM (I don`t know the airbus procedures) you put the oxygen mask on, talk to your partner to see if he is ok (bad time for a pilot incapacitation) and then analyse... structural damage or not? Only after that you can start the descend and turn wherever you want! . .. .Cheers <img border="0" title="" alt="[Wink]" src="wink.gif" />

[manuel ortiz]

Spodman ,. .. .Now , don't consider the turn as your only option.. .In some cases you may have the time to coordinate with ATC and staying on the airway may represent the best course of action due to terrain or traffic.. .. .An emergency descend can have different reasons and levels of urgency to be executed .. .We all know the scenario for which we train the most but you can also find yourself in a situation which perfectly allows for a more prepared and coordinated event.. .. .Rgds. .. .manuel

[tired]

The answer to this depends entirely on where you are.. .. .If you're on an airway in one of the more distant parts of the world - NAT tracks, Africa, Siberia, Northern Canada etc etc etc - then IMHO it makes sense to turn off the airway (giving due thought to high ground etc) as soon as you can. The most likely place for conflicitng traffic to be is on the same airway as you are. As for contacting ATC first, well in some of those places........ .. .If you're in congested airspace - Europe, New York TMA, LAX TMA etc etc - then you've probably got an equal chance of hitting other traffic whatever you do - turn, or continue straight. The safest thing then, if you've got the time, is to talk to ATC before you start down (but the emphasis has to be "if you've got time"!!). .. .It's horses for courses.....

[Fat Boy Sim]

Forty five degrees of bank and nose down twenty degrees....Gulp!!!

[Spodman]

Thanks for all the information. It appears almost anything can happen!!

[mcdhu]

Canada, also, expects you to turn to the right. See the Aerad FIS under'In-Flight Contingencies'.. .Cheers. .mcdhu

[RedUnderTheBed]

Turning away from any danger is the trick. NAT tracks etc have specified procedures for this.. .One skipper in our mob always briefs a turn towards the equator. When I asked why he replied; "The water's warmer.". .. .If all other things are equal... <img border="0" title="" alt="[Smile]" src="smile.gif" />