Airbus procedure : ask clearance before emergency descent ?

[C.M]

About 2 years ago I came across a synoptic list of changes in Airbus procedures, and one of them required pilots to ask for ATC clearance to initiate an emergency descent . Can someone direct me to where this issue is reflected in any airbus manual since I cannot find it ?

(P.S : Such procedure is already ask by in i.e the German airspace rules and regulations , it could be the case that Airbus took such issue and incorporated it in its procedure)

[FlightDetent]

Do you have a reference to the German proc, that we need a permission before EMGD? :E

[C.M]

Not anymore . I had access to CRARs (Country Rules And Regulations) but not for now . I was reading something in the German CRAR where it was prompting pilots to ask for a descent clearance even in emergency because of German airspace being so congested . I read that shortly after changing procedures in my previous employer ; we were requesting clearance in emergency descent , the justification being basically what I saw in the German CRAR. But it wasn’t until I saw the list of changes in Airbus procedures that I realized it was probably Airbus itself which probably mandated this . The thing is , you will not find this in their manuals.

[fantom]

Never mind all that. If you need an emergency descent, just do it. It is the job of the controllers to manage their situation.

Airmanship.

[FlightDetent]

C.M., welcome to the forum, I forgot to say that at the beginning.

You have me perplexed a bit. The whole idea that you'd need somebody's clearance to start emergency descent is completely out of this time-space continuum. I do not think that's what you ment, but without a reference it is hard to discuss.

Current AIB procedure here:
3956

AIP Germany: did not check, not available online f.o.c.

LIDO eRM CRAR Germany: nothing there and I assume the publishing house does have that one right

FCTM: not in the latest...

What you may have seen is a re-location of the ATC ... advise item in the procedure flow, which happened around the time FCOM went digital. But that whole PNF loop was cancelled altogether.

The main reference would then be ICAO Doc 7030 Regional Supplementary Procedures - EUR (https://www.icao.int/EURNAT/EUR%20and%20NAT%20Documents/Doc%207030%20-%20EUR%20and%20NAT%20SUPPs/EUR%20SUPPs%20working%20copy/Doc%207030%20(EN)%20-%20Edition%205,%20Amd%209+APP%20[EUR].pdf) para 9.1.1 and 9.1.2.2.(b)

[compressor stall]

Could it be that you were seeing the effects of a change to the operating procedure introduced by Airbus some ~6 years ago where there was a line item before the commencing the descent of announcing Emergency descent to the cabin.

It changed again 2-3 years ago with - as I understand it - the A350 certification and CCQ differences where that same announcement to the cabin is now made on the descent.

For the last decade or more, unaltered A320 Airbus procedures has ATC announcements have always been made in the way downward.

[C.M]

Flightdetent , believe it or not (as I have mentioned in my second post ) the request for a descent clearance to perform an emergency descent became a procedure where I used to work before . The actual callout from the pilot flying to the PM became “ Emergency Descent - request descent “ . Whether I disagreed or not it became a procedure.
Not long after we came up with this procedure I was reading some CRARs (I believe it was for Germany ) which actually mentioned that the airspace is so congested that pilots are to advise ATC ASAP of intenting to perform an emergency descent ( no one will deny the initiation of course but it gives the controller an immediate plan on how to divert traffic immediately below you ) . By the end of the month I will have again full access to all those CRARS and check that again .
Now let me go to the Airbus thing I mentioned . It was a list of changes made to procedures ( given as sections to their manuals along with a very brief justification for the change .... one of the changes had a justification going like this “ the change is to reflect the need for pilots to request clearance when intending to perform an emergency descent especially over congested airspace... “ ... this is not the exact statement , but pretty much the nature of what it was saying . It was really bad I didn’t check the specific section it was referring to , and all attempts thereafter to locate it didn’t lead anywhere .

[C.M]

By the way thank you the document . I did check the relavent sections . Section 9.1 says “ initiate a turn away from the assigned route or track before commencing the emergency descent; “ Considering how slow aircraft turn at high speeds / altitudes , there will be adequate time for ATC to be notified before the aircraft establishes the new heading to commence the emergency descent .
But when talking of ATC procedures , individual needs of each country might be different that’s why they publish CRARs and maybe one of them might include (or have included ) what I was talking about .
Give me sometime to gain complete access to all that stuff and I’ll dig it out

[RAT 5]

I think one of the things that can cause a 'once in life time, not very much practiced procedure' to go wrong is when it is rushed. The major reason for a 'startle/surprise' emergency descent to be performed is the pressurisation scenario. We assume that pax & crew are on O2. The a/c is controllable. ATC is part of the team. Some are better than others and will help in differing qualities.
Consider; the first ATC see is an alarm on their radar that XYZ is not maintaining FL. What is their first reaction? After a WTF startle moment it will be to instruct XYZ to return and maintain their FL. They have no idea what is going on. Hole No.1. XYZ's check list does not include 'TA only' as a recall priority time. Shortly after commencing a 'shuttle entry procedure' XYZ gets an RA that reverses the decent. They ignore it. The a/c that is the impending target then starts shouting at ATC, WTF, or reacting to their RA and alerting ATC to that fact, who blocks it out because they are calling XYZ. Holes No. 2 & 3. Then other a/c start getting RA's and calling ATC who has by now lost the plot because they have no idea if XYZ is under control or not. There is a bowling ball hurtling downwards and hoping to miss the skittles.
In the sim, after the rapid depressurisation bang, it was very common to see 2 pairs of arms flying around the cockpit like 2 orang-utans on acid. Communication and awareness broke down. Rushing this a great way to convert a manageable scenario into a right mess.

Or: "Mayday x3. XYZ FL 370 HDG 250 emergency descent." ...'Roger XYZ turn left 30 degrees descend FL 250 call you back." ......."ABC turn right 30 degrees."..........."XYZ maintain HDG decent FL 100."......"DEF matin HDG. HIJ....turn left 20 degrees.......MON maintain HDG. All aircraft, XYZ is making an emergency descent HDG 220 FL 100. You may see this on TCAS."

How long does that take? ATC is part of the team. CRM techniques are not limited to the flight deck. A successful outcome is the objective. Why not give yourself the best chance. 15 extra secs is not going to make it a failure. 15 secs less just might. IMHO.

Emergency decent training & checking was not the best quality in airlines I've experienced. There was not a lot of imagination in the scenarios. It was often a 'tick the box' exercise with a rapid depressurisation and a 'do it by numbers' exercise. Not necessarily a bad thing as that allows training to kick in when required. But, there are more reasons than just a rapid depressurisation. Indeed, most real events are subtle depressurisation. Imagine a bleed or pack trip in the climb. It resets, but then fails again. You decide to continue climb as MEL/DDG allows you to do so. Then, still climbing the remaining pack starts to falter. What do you do and how do you do it? What about if you are at cruise on a single pack, fed from one bleed, and that bleed trips and does not reset. Can the pack be fed from the other bleed without problems? How long do you have to consider? Do you descend straight away while you consider? How do you descend and organise with ATC? There's training and there's checking. The former needs reflecting on what have been real life events. Training = education. Checking is different. I've heard of crews who forgot the packs after takeoff; got pressurisation problems at FL 130 and made a full emergency descent, including dropping the masks, to FL 100. Hm? It's a complicated subject and needs some thought in training & execution.

I expect many differing opinions, and as the scenario is no longer a possibility for me, I'm not that fussed, but am interested in the debate; mainly because there are so many differing philosophies both in the air and on the ground. I heard a couple of years ago that ICAO was looking to design a worldwide standard technique. Good luck with that, because it needs to be so, but the obstacles to standardisation will be formidable.

I know this thread was started as an Airbus discussion. I'm not sure how a type influences the technique for this manoeuvre. Surely this an ICAO matter not a manufacturers. Also, I do remember the issue of emergency descent technique, not by type, being thrashed out on here a few years ago, but to no conclusion.

[C.M]

RAT 5 I agree with everything you said . I agreed internally upon thinking about it after the procedure was introduced 2 years ago.
there are situations that force me to produce evidence ( the original documentation) of things I have read , and with a vast amount of dispersed technical / legal information out there it’s sometimes hard to trace the original source

[FlightDetent]

Just not to lose focus.

- There is no, nor has there ever been, any procedure from Airbus to delay starting the emergency descent pending an approval from ATC. As well, no manufacturer has any authority to issue such guidance.

- There is no requirement, in ICAO or national CAA level to do the above either.

Awareness, wide co-operation as mentioned by RAT5, and taking smart choices, absolutely YES. But no rule.

[Denti]

When talking to ATCOs over here in germany one thing becomes quite clear: In case of an emergency descent even more important than telling them that you do that is squawking 7700. The reason is the very densely used airspace, which in turn means very small ATC sectors both laterally and vertically. Additionally there are different agencies controlling different altitude bands. And usually aircraft that fly below or above the sector an ATCO works are filtered out so he can't see them, based on either Mode S ID or squawk.

However, 7700 is displayed on all sectors regardless of other filters and they can start much sooner to clear the path.

[RAT 5]

In case of an emergency descent even more important than telling them that you do that is squawking 7700.

Nice theoretical idea, if possible. Rapid depressurisation, we are told, can cause severe misting and low vis. Not to mention the plastic face masks. If the reason is other than that it shud be no problem. That is alerting ground based agencies: I still think TA Only is a huge priority for our end of the procedure, but appears far to low down the checklist for my comfort, and well educated professionals should be able to find that knob in the dark. IMHO it was one of the first things I did from memory; even though I was told it was wrong as it was not a 'recall' item. Oh dear.

[C.M]

I still think TA Only is a huge priority for our end of the procedure, but appears far to low down the checklist for my comfort,
RAT5 I assume that is a non Airbus related checklist , correct ? Setting TA only is not part of the Airbus emergency descent checklist ( neither as it appears on ECAM or the QRH)

[RAT 5]

Setting TA only is not part of the Airbus emergency descent checklist

Really? Not sure what it has to do with type. It is an airmanship and ATC matter, not type related. Years ago, about 2009, there was Eurocontrol bulletin, I think #9, highlighting this issue. I brought it to the attention of my Boeing operator. It did not appear in the Boeing or company checklist. It took a while for 'the eyes to open' and for them to understand, but it did eventually arrive into the checklist. Eurocontrol's advice was that anything which compromised the normal performance capabilities of the a/c should result in electing TA only. At the time the only B737 checklist that did this was an engine shutdown; and even then it was No.9 on the checklist, i.e. a long way down the checklist. In the sim I watched crew take a long time to reach and action this item. Given that all the engine failure scenarios were conducted at low level and the check list actioned in level flight, there was never a problem. Hence, perhaps, a lack of appreciation to the consequence in the real world. Now imagine an engine failure at cruise level and a descent required. As always ANC. To protect the a/c and organise the descent will take priority, then the checklist will be actioned possibly during the descent, unless a drift down delays the descent. Thus the a/c can be descending quite a few 000' below cruise before TA Only is selected. Not a good time to have an RA with which you can not comply.

[C.M]

Really? Not sure what it has to do with type. It is an airmanship and ATC matter, not type related
I can understand setting TA in case of engine failure . It is very likely you will not have adequate performance to comply with an RA command and when dealing with an engine failure things tend to move rather slowly giving adequate time for an ATC arranged separation
But in a very fast moving scenario such as an emergency descent ( for the Airbus you can reach about 6000fpm in a typical emergency descent configuration ) I would tend to believe that if the system detects the need for an RA during such rapid descent it’s sure better to comply and accept the lower rate of descent rather than risking an actual collision. In a congested airspace such as Maastricht , Germany , overflying London TMA ,etc the controllers will sure try to arrange a separation during a descent but such instruction may not reach each and every individual aircraft on time . I would like the hear the perspective of a controller on this matter

[Denti]

Interesting topic, as the emergency descent should be flown on automatics if possible and some busses can and do fly TCAS RAs automatically that would be indeed interesting to see that. As mentioned above the minibus can reach quite high rates of descent, i have done over 7500fpm in normal operation already, the autoflight system will probably be challenged by an RA.

I doubt ATCOs do read this forum, but you can post something on their part of pprune, and they will surely answer.

[C.M]

I will probably post this sooner or later . But so far there is not a single advice from Airbus it self (in any manual) for setting TA only during an emergency descent , and I have been in sims with TREs from Greece, Austria, Germany ,UK and it was never brought up

[RAT 5]

when dealing with an engine failure things tend to move rather slowly giving adequate time for an ATC arranged separation

A crew I knew had an engine rundown, at night, FL370. There was the startle factor, and they went for the Engine Malfunction analysis first. Very very quickly they got the stick shaker. And then what. The recovery at FL 370 will lose you >2500'. Thinks move faster than you think. And in that stall recovery you get an RA; then what do you do? Meanwhile you haven't contacted ATC yet during the WTF moment. There's more to TA only than an engine failure scenario. Read the Eurocontol bulletin as to the advisory reasons for TA only. Reflecting on the various airline training I've had over a career the appreciation of the TA Only selection was mis-understood and thus ignored and pilots were left in the dark; no discussion. If it wasn't in the checklist then it is not necessary attitude. When I put this scenario to a Boeing pilot I was told "I think TCAS will take care of it, but perhaps we need to consider it." IMHO thinking is not enough in a scenario when you need to be certain. I suspect he was thrown by a Eurocontrol advisory that had not drifted across to the USA yet, where they consider they rule the roost. Except they don't and that is why the Boeing Emergency descent checklist has 10,000' in it. Why? Trans Alt in USA is 18.000'. At 10,000' above UK you are in controlled airspace where the law says you mustl be on STD at a FL. Once, in the RST sim, I was told it was wrong to descend to FL 80 over UK. Hm. I doubt ATC will let you swany around at 10,000' amongst everyone else at FL's.

[C.M]

We are talking about a different kind of “moving slowly” . When saying things move slowly , I meant how the plane is self maneuvers in the 3D environment . Due to how the Airbus has its procedure set up during engine failure at high altitude , It’s drift down is slow . By the way what section of the advisory has the TA only ? It’s not in 9.1
You do acknowledge that there is a merit to what I posted before ... the scenario of an airplane doing a descent with a rate of 6000 rpm and more in an area such as Maastricht has the potential of ending up as I indicated before

[RAT 5]

"By the way what section of the advisory has the TA only ? It’s not in 9.1"

This is copy/paste from Eurocontrol ACAS II bulletin #9 July 2007.

Degraded performance:
TCAS II provides maximum benefits when operated in RA mode and when all RAs are followed promptly and accurately. However, when the aircraft performance is degraded (e.g. an engine failure, an emergency descent, etc.), it might not be possible to comply with a “Climb” RA.
Therefore, airlines must define clear procedures to address degraded aircraft performance situations, having in mind that:
• When operated in RA mode, non-compliance with an RA will adversely affect the efficiency of the coordinated RA triggered on- board the other aircraft.
• When operated in TA-only mode, collision avoidance is still maintained by the TCAS II of the other aircraft
The use of the TA-only mode is described in the following note that will be included in the next version of the ICAO PANS-OPS, Doc 8168, due in November 2007:
“Note 2. - The normal operating mode of ACAS is TA/RA. The TA-only mode of operation is used in certain aircraft performance limiting conditions caused by in-flight failures or as otherwise promulgated by the appropriate authority.”

Note the comment: "airlines must define clear procedures.........." When I brought this to my Flt Ops attention there was a blank stare, especially as there had just been an extensive RST program emphasising emergency descent procedures. It took a good long while but it crept into the QRH eventually. However, it was the most missed item in any exercise. When I suggested the whole matter of TA Only should be discussed, especially on command courses, the blank stare reappeared. Is it going to take a mid-air to open eyes.

[Vessbot]

A crew I knew had an engine rundown, at night, FL370. There was the startle factor, and they went for the Engine Malfunction analysis first. Very very quickly they got the stick shaker. And then what. The recovery at FL 370 will lose you >2500'. Thinks move faster than you think. And in that stall recovery you get an RA; then what do you do? Meanwhile you haven't contacted ATC yet during the WTF moment.

Surely you're not suggesting that this crew should have prioritized the changing of a transponder setting over flying the airplane during this "WTF moment" that led to a stick shaker?

[RAT 5]

Absolutely not. My point was about things moving faster than you think. i.e. they forgot to ANC when the a/c was severly compromised in performance and instead firstly went for a check list. If they had done ANC then the stick shaker would not have occured.
But, there is a team of 2 pilots and PF can do the AN bits & PM might have the capacity for some C bits.