Emer.descent time limits.A320.

[Sergei.a320]

Hello everyone! In previous version of FCOM ( BEFORE NOV 20). In special operations chapter- flight without cabin pressuriz-n. There was a profile that stated that we're able to fly for 30' max above FL140 and below FL180. After Airbus updated the FCOM and deleted all performance data from it, they moved this special ops chapter to supp. procedures and deleted this profile data. So my question is : How long can we fly above FL100 in case of emergency descent in mountanious area where MEA/MORA is above FL 100. Lets assume that MORA is 12700 and time to des and overfly mountains exceeds 15 min (oxygen)...maybe you have regulation/fcom refernce?

[vilas]

Perhaps this may do.
Supplemental oxygen requirements:[EASA Air Ops Annex 1 to VIII, §NCC.OP.210] The pilot-in-command shall ensure that he/she and flight crew members engaged in performing duties essential to the safe operation of an aircraft in flight use supplemental oxygen continuously whenever the cabin altitude exceeds 10 000 ft for a period of more than 30 minutes and whenever the cabin altitude exceeds 13 000 ft.

[Sergei.a320]

that's what i need!:)many thanx!

[FlightDetent]

Not enough. There were about 4 limitations embedded in that graph.


https://cimg4.ibsrv.net/gimg/pprune.org-vbulletin/939x342/snippet_depress_464a8d68cbf3b55a7794a83f8d3db46eb3655228.png
This one's enhanced with 21 min. pax containers.


Besides: NCC.OP.210 refers to ANNEX VI Non-Commercial Air Operations with Complex Motor-Powered Aircraft [Part-NCC] although the wording in CAT.OP.MPA.285 looks identical.

It's CAT.IDE.A.235 Supplemental oxygen — pressurised aeroplanes that you are looking for, in the EASA world.

This is the original FCOM text
PASSENGERS

For flight at cabin pressure altitudes above 10 000 ft, up to and including 14 000 ft, there must be enough oxygen to supply 10 % of the passengers for the flight at those altitudes that lasts more than 30 min. For flight at cabin pressure altitudes above 14 000 ft, up to and including 15 000 ft, there must be enough oxygen for 30 % of the passengers. For flight at cabin pressure altitudes above 15 000 ft, there must be enough oxygen for all passengers.

That's two. Another one you're looking for is the 120 minutes for flight deck crew (hence we theoretically switch oxy mask to NORM after the EMERG DES is completed.

Last is the CS-25 requirements, somehow reflected in the MMEL. There's a restriction for max alt 31500 ft when 1 Bleed is INOP and you do not have speedbrakes. MMEL-MI-36-11-01 "E".

[Sergei.a320]

FlightDetent

Perfect! That's really useful! And about you FCOM qote .. when they talk about cabin altitudes, when aircraft is depressurized ,does it mean actual altitudes(FLs)?;)

[Reloald]

Get as much drag out as passable: spoilers, gear, and so on and dive as quick as possible. Mmo/Vmo.

[vilas]

VMO/MMO with gear down? You may not have gear for landing.

[FullWings]

...How long can we fly above FL100 in case of emergency descent in mountanious area where MEA/MORA is above FL 100.
Until you are clear of the mountains? :)

[mustafagander]

After spending many decades in long haul ops and especially over Afghanistan and China as well as trans oceanic, I really hesitate to extend gear for an emg descent. What if there is airframe damage unknown to you busting hydraulic lines? Gear down in the middle of the Pacific - you're going swimming. In other areas it's a complication you just don't need today.
Then there are the considerations about accelerating to Vmo/Mmo. Any airframe damage? In a deco event my old mob had Boeing is reported as telling management that accelerating to max speed would likely have caused a hull loss coz there was significant airframe damage unknown to the pilots.
As for staying high the procedures were frightening on the notorious "Silk Road" route with altitudes required to be abv F220 for quite a while, then F140 for a long time as I recall it. The diversion would take over 2 hours. All capped off with a landing in a busted aircraft in a high altitude shortish strip with minimal nav aids.
So then, have a long think about potential emg descents and "armchair fly" them several times so you really understand what is likely to happen on "the day". When I was still flying, almost without exception Cpts would plan to maintain crz speed and accept a longer time to descend. Think also how long it takes to extend the gear when decelerating to Vlgo prior to descent. Boeing figures tend to show, B747, that you barely gain any time and you are higher for much longer. Bad for the pax.

[FullWings]

I agree. Much better to have a controlled step down with plenty of CRM and SA, than to try and shave seconds.

When I brief for emergency descents, I often ask what people think the most important action is. Yes, we don’t want to hang around for afternoon tea at FL390 but getting your own oxygen mask on and working is critical. If that doesn’t happen, everything else is irrelevant....

[vilas]

FullWings

In Emergency Desc the emergency part is over with donning mask and communication with PM. Rest is a descent with speed brake with adaptations as required. If you had to spend a little time at 13000ft without supplemental O2, I don't see that happening but is OK. Airbus has changed the procedure where after memory items i.e. donning mask and initiating descent and turn, pulling present speed rest is read and do from ECAM/QRH.

[pineteam]

I would not worry too much about flying without oxygen at 13000 . It was pretty common practice in Zambia on the Caravan and the twin pistons. Was funny to see all those old people falling asleep so easily and farting quite often. I still remember one american passenger who was also a pilot trying to tell me that was illegal and dangerous. That was cute.

[vilas]

What was illegal? Depressurized aircraft or passengers depressurizing themselves?

[pineteam]

Flying at 13000 feet with no oxygen masks for the pilot or passengers.

[vilas]

AT 13000ft upto 30mts is legal for crew. Beyond 13000 crew need O2. Passengers can go even higher with some O2.

[FullWings]

I think there are some airfields in places like Tibet in the 14-15,000’ altitude range that take jets. That must be interesting in terms of SOPs and pressurisation. I presume they must be modded to stop the masks dropping when the cabin alt goes up on landing...

[pineteam]

On the A320 we have an optional '' HIGH ALT LDG '' push button switch on the overhead panel that you would use in case you operate to airport with an elevation of 9200feet or more which will only drop the oxygen masks if the cabin altitude reaches 16000 feet instead of 14000 feet.

[vilas]

FD Can you explain that graph in detail?

[KingAir1978]

Vilas, this graph is a profile that Airbus developed for airlines to analyse their routes. If you couldn't go straight to 10.000' you could follow this profile to develop escape routes. This particular one seems to come from the Airbus 330, which has 22 minutes of oxygen for the pax. If you're routing across the Himalayas your company should develop escape routes (laterally), to get you to 10.000' with the available oxygen on board (by following this vertical profile at the most critical point of the route). During the 'cruise' at FL140 first aid oxygen can be used.