The safety briefing before flight explains the use of the drop down oxygen masks. People do of course pay attention to that, don't they?

There is an expression in aviation for priorities - 'Aviate, Navigate, Communicate' in that order. Passengers not immediately being told what is happening is not going to kill them. A PA can wait until a suitable moment, carrying out an emergency descent is not a suitable moment.

One of things not much thought about with the A380, great aeroplane that it is, is the lack of airports able to handle it. A large aircraft diversion stretches any airport not accustomed to handling one so an A380 in BAKU is a headache for the airport, airline and passengers.

Why not simply continue until reaching a more suitable airport, after all the A380 has 4 engines and is apparently designed to reach a such and not divert into any hole .... :}:}:}

(sorry, is only meant to make the super-jockeys jump ..... )

" all the A380 has 4 engines "

Not quite. There are 119 of these aircraft in operation that makes 476 engines.

Paper towels
 

On the ATP when the crew said there was whistling from rear door we packed it with towels and told them to worry when the whistling stopped.

:E

4 or 2 what's the big D they were all working,would be great to find some place more suitable but Baku is the only in the vicinity,Turkey few hours away as well as Emirates

how big a leak is needed?
 

An element of this incident that puzzles this non-pilot is the relationship between the probable scale of the door-seal leak and depressurization.

I have the impression that in normal conditions the air paks provide considerable excess flow which only fails to over-pressurize the aircraft by leaving through a large outflow valve.

Presumably a fault in a door seal alone would need to leak more than the normal discharge of the outflow valve in that state of flight even to cause a reduction in cabin pressure. Of course if there were other abnormal leaks, or the outflow valve or controls suffered a simultaneous fault which prevented it from closing sufficiently, then a door seal leak could push an already degraded operating point past the edge.

Too much speculation--so I'll switch to questions.

Do people here have actual experience of a door-seal leak alone (which I understand to be common) causing a cabin pressure departure from allowed limits in an otherwise fully healthy aircraft?

Approximately what is the normal outflow air flow through the valve at cruise altitude?

What do you mean, outflow valve only regulates cabin altitude by differential pressure in cruise within about 7-8psi at this altitude

Who knows what flow rate is out of that valve, it's operated by computer and varies according to flight phase

As an Airbus (not 380) Capt, your:is about spot on :ok: A leaky door seal is hardly rare, and just makes an annoying noise. I think Packs / Pressurisation are designed to cope with 1 (or more?) windows blown out.

We'll see, seems to me pretty standard decompression, flown correctly, land. It is also pretty standard Pax are frightened / alarmed / think they were going to die *...

NoD

PS * and they are unlikely to be "reassured" by the Captain trying to make a PA whilst wearing an Oxygen mask :ooh:

I'm with you archae86 . I don't think a leak in a door would be, by itself, enough reason to depressurize an A380 to the point of deploying oxygen masks. There has to be something else, that was not disclosed yet.

When a "slow" depressurization occurs, pilots get an ECAM advisory indication and, if incapable of solving the problem, they may start the emergency descent in order to reach the cabin altitude before oxygen masks deploy.

There are, of course, other reasons to deploy the masks even when reaching cabin altitude "in time". Minimum obstacle or of route altitudes, come to mind.

As usual, lets wait and see...

If I may respectfully beg to differ...

An aircraft door is not designed to leak nor should (in these days) an aircraft be knowingly flown with a reported door leak problem. Never mind the quotes about 'noise being heard' and 'doors being checked' the photographic evidence alone shows there was a major problem with the door.

I'm sure the apparently craggy old long-timers will talk about stuffing wet rags in the holes and nicotine stains on the fuselage etc but that was then, this is now and it's unacceptable.

Have you ever flown in an AA 757 from Man to ORD in the emergency exit row? I have many times and all their doors are leaky. To the extent they made up "hot" water bottles as the interior walls were that cold. Old BA 747's the same. Did I panic once and say impending doom was all around me? No thank goodness stiff upper lip and all that!!

Get a life for God's sake and stop whinging!! You make all us SLF's sound paranoid.

When I refer to "standard decompression" I mean the actions of the crew / perceptions of the Pax. Steep "terrifying" dive, shortly after it started masks came down (shows crew ahead of the game), dove ~20000'+, no PA, Pax all frightened.

That to me is "pretty standard". There is no "pretty standard" cause, and is not terrible relevant to the crew or their actions at the time - you deal with the symptoms.

You'll find a lot of cancelled flights then ;)

There is, to the best of my knowledge, no way a "rapid decompression" will happen solely due to a faulty door seal. It would take more fundamental door problem... Whilst not want you might want to hear, but we tend to "carry leaky" door seals until a convenient time to repair them - and often after the door is opened / closed, the problem goes away.

NoD

How long would "decent" ~20000' dive take pls Nigel?

That's right and the outflow valve will just shut trying to keep cabin altitude, bleed demand will increase and all that

Considering there was no exploding decompression they'd keep max speed and it'd take about 4min

No it doesn't. What it shows is that a problem occurred en route.

Sounds to me as if you are agreeing with the previous poster's point:

Granted, a leaking seal doesn't endanger the aircraft or mean the door is about to depart, but purely on the grounds of passenger discomfort (both noise and temperature), "unacceptable" strikes me as a pretty apt description.

(descent) The Pax say was ~2mins - probably approx right. You can get significantly more than 10,000'/min, but it takes time to get that going, and also level off.

There are 2 descent profiles - 1 if you think there may be structural damage, the other if not. In the latter, it is idle, full speedbrake, as fast as you can go. In the former you are more restrained :ooh:

Crew and Passengers can survive for a long time on Oxy Masks at cruise altitude, albeit cold. However, the assumption is that some in the cabin will not have listened to the Safety Video, and will not be on oxygen. They have ~15s of consciousness and 3mins to possible brain damage. Very roughly, once below 20K' the brain damage issue has gone. So you can see the priority...

Usual aim is to level at 10K', but terrain may limit that and around Baku is a factor.

EMER DESC
 

If I remember correctly the magic sequence after oxy masks on and establish communications is:
TURN/PULL (ALT) - PULL/TURN (HDG) - PULL (SPD).

All kinds of auxiliary tasks by PM of course and second round for both PF and PM.

If I remember correctly then MAN OXY ON is a checklist item (the so-called 'lawyers switch' - you manually deploy oxy masks even if they have been deployed automatically already.

Emergency descent is never initiated by the aircraft. If nothing is done the crew (and pax) would fall unconscious eventually, A/P would maintain FL and everyone would perish while F16 (or MiG 29) pilots watch the aircraft run out of fuel and dive (remember Helios?).

After emergency descent initiation, communication with the Pax goes out of the window as pilots will be busy checking MSA, range at lower level, diversion airports etc.

Job well done by flight deck crew it seems!:D

A night at Baku airport without water is a survivable event (unlike slow or rapid decompression at FL380 without action being taken by the flight crew).