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SQ B772 returns to SIN after loss of cabin pressure

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SQ B772 returns to SIN after loss of cabin pressure

Old 2nd Feb 2008, 14:05
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SQ B772 returns to SIN after loss of cabin pressure

http://www.channelnewsasia.com/stori...326502/1/.html





SINGAPORE : A Singapore Airlines Boeing 777-200 plane flying to Beijing had to return to Changi Airport some 90 minutes after takeoff due to loss of cabin pressure on Saturday afternoon.

Officials say Flight SQ 802, carrying 232 passengers and 13 crew, suffered loss of cabin pressure at an altitude of 36,000 feet.

So the pilot sent the plane first to 32,000 feet and then to 10,000 feet.

Because of the rapid 6-minute descent, oxygen masks were deployed.

However these were safely removed once the plane reached 10,000 feet, and was stable.

SIA says the captain, in accordance with safety procedures, immediately initiated a return to Singapore - the nearest suitable airport.

The plane landed safely and without incident at 1.48pm local time.

Passengers were transferred to a different aircraft to continue their journey to Beijing.

SIA says a detailed investigation is underway and apologises to passengers inconvenienced by the delay. - CNA/ch
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Old 3rd Feb 2008, 08:04
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If you are at FL360 and 90 minutes out of Changi then the 'nearest suitable' airport isn't Changi, but, provided the condition was contained then I would have opted for a low level return to my base where sorting out the problem would have been a lot easier than, say, Dar Nang.
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Old 3rd Feb 2008, 08:29
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Parabellum,

If one or more of your passengers died during your low level return to base as a direct consequence of oxygen deprivation earlier, and you had elected not to proceed to the nearest airport, you would need a very good lawyer to get you out of charges of gross negligence and involuntary manslaughter. Passengers may seem "alright" after a rapid descent, but with 300 or so passengers on board, there will be some with heart ailments etc., who need to get on the ground fast. Why take the risk?
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Old 3rd Feb 2008, 09:22
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Low Level returns to base may not be a problem in Australia, but overseas they could be a nightmare.

Cruising along in an airliner at 10'000ft is far from ideal.

High terrain, Military airspace, Restricted airspace, lack of communications, and controllers that probably have no understanding of what you are doing and where you are going.

As a first rule, it is generally best to land as soon as practicable! After that, anything is possible.
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Old 3rd Feb 2008, 10:10
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Nearest Suitable does not mean Nearest Usable ! (Unless you are on fire )

For example, LHR-JFK, pressure loss at 10W. Shannon may be nearest and suitable and usable, but availability of replacement aircraft, medical facilities, crews, engineering etc. means that the contained situation makes the return to LHR more Suitable.
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Old 3rd Feb 2008, 10:25
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Whatís the difference in terms of safety if an airplane (a SE or a WB) flies at FL100 or FL360 in a controlled airspace? It is safer only at higher levels, isnít it? Ok, those fellows that died on a B737 collision in Brazil thought the same.
If there is not a medical urgency or any other situation that affects the aircraft performance, a pilot doesnít need to rush looking for an immediate landing after a (rapid or slow) depressurization. Everyone knows that a jetliner can fly very well (nicely and safely) at FL 100 otherwise I canít imagine how short sectors (including in congested airspace) can be made. Searching for options in that area itís easy to find out that VVTS, Brunei or heading to HKG arenít better than a 180 degrees returning to SIN, coincidently SIA home base, a place with a good support, several hospitals and an extra airplane as well.
Crews must not fly an airplane considering what a lawyer would say. They should consider first what is the appropriate option for everyone involved, including their company Ö this is part of their CRM I suppose.
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Old 3rd Feb 2008, 11:18
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Hamil,

A rapid depressurisation is a serious event. Not all passengers are able to put on their oxygen masks. Not all drop down as they should, and the elderly, young and infirm will not always put them on. To then put them through additional, unnecessary unpressurised flight at 10,000, exposing them to further oxygen depravation for the sake of keeping the Company happy, is not only irresponsible but dangerous.

Hospitals are not much help to you if you are already dead.
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Old 3rd Feb 2008, 11:27
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It doesn't say "rapid depressurisation" anywhere in the article - it might have been a slow loss of pressure due to a leak or faulty valve or something. If that was the case, surely an alarm would have sounded as soon as it started to become unsafe... it doesn't necessarily mean the passengers were being starved of oxygen for a period of time, as would happen in the case of explosive decompression and subsequent inability to put on an oxygen mask. It sounds to me like, in this case, there was very little drama.
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Old 3rd Feb 2008, 11:28
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Just one man's opinon, but this looks very much like a commercial decision.

Knowing Singapore a little, I think it unlikely the commander made this decision without a fair amount of prior consultation to the company.

get-home-itis again?
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Old 3rd Feb 2008, 12:33
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Not all passengers are able to put on their oxygen masks. Not all drop down as they should, and the elderly, young and infirm will not always put them on.
...don't forget that these masks are mostly for decoration and "a good feeling" only, the positive effect in terms of O2 is very small, ask any doctor.
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Old 3rd Feb 2008, 14:23
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Personally I think it's wise to divert to a city that at least has some half decent restaurants!

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Old 3rd Feb 2008, 15:09
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A rapid depressurisation is a serious event. Not all passengers are able to put on their oxygen masks. Not all drop down as they should, and the elderly, young and infirm will not always put them on. To then put them through additional, unnecessary unpressurised flight at 10,000, exposing them to further oxygen depravation for the sake of keeping the Company happy, is not only irresponsible but dangerous.
Rapid descent can be a serious event but it is not a Russian roulette where some passenger will die or suffer severe injuries. After reaching a safe altitude F/Aís have to check cabin area and if medical assistance is required a decision to land as soon as practical should be considered. If the situation is under control there is absolutely no reason to put a loaded 777 in Ho Chi Minh or Brunei, for instance.


...don't forget that these masks are mostly for decoration and "a good feeling" only, the positive effect in terms of O2 is very small, ask any doctor.
Sorry man, if you are sure about it this is a premeditated crime. Therefore, Boeing, CAAS and SIA must be prosecuted.

get-home-itis again?
Not really. Air-ground coordination is one of the possibilities to use ACARS. That`s why airlines invest a lot of money to install it on every airplane.
Captain`s decision must be based on several aspects and returning to SIN, 90 minutes away, over the South China Sea can be considered as a good decision in this case ... or am I wrong?

Personally I think it's wise to divert to a city that at least has some half decent restaurants!
If someone likes spicy food or some strange broth SIN is a perfect place for a stopover
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Old 4th Feb 2008, 00:05
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Worn out rubber

"I would have done it this way because I've sat in front of a mirror and pretended this very scenario happened to me. I made up my own words, and I didn't panic. And now, seasoned aviator or aviatrix that I am, though I've not actually flown a real airplane, I can categorically state without reservation or shred of humility that the SQ fellow, seasoned aviator, unlike me, made a grave error of stupendous proportions and he better watch out because, because, because..."
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Old 4th Feb 2008, 05:39
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Regarding a rapid depressurization and subsequent actions, we do not know the full details of the SQ incident, and indeed whether they suffered a rapid depressurization at all.

However, if we look at an event in detail, we can perhaps work out the best option if it really does occur.

1. There will be an initial loss of pressure, which may be very sudden, and may be accompanied by an increase in noise and sudden changes in temperature.
2. The oxygen masks should now auto deploy. Some, however will not. (As demonstrated in Air Tests).
3. The passengers, now probably in a state of mild, moderate or extreme panic will (perhaps) put their oxygen masks on. Some will take a considerable time to put them on, others ( especially the young, elderly or infirm), may not even put them on at all.
4. About 6 panic stricken minutes later the aeroplane levels out at say, 10,000 feet, and the passengers remove their masks.

The cabin attendants can now assess the state of the passengers.

However, how do say 14 cabin attendants, who are not doctors or qualified nurses make an accurate assessment of the medical condition of say 300 passengers,who have just experienced a rapid depressurization?

The passengers may appear to be alright, but what is their real condition?
How much have they been affected by the event?
Did some of them not have their masks on during the descent?
Do some of them have heart ailments, and are perilously close to having a heart attack?
The majority of passengers will also probably be in a state of shock.

So what is the best course of action for the Captain now? (Assuming of course, the aeroplane structure is sound, and the cause of the rapid depressurization has been identified),

A) Not land at the nearest suitable, and land somewhere else where they may be a replacement aeroplane. Fly there at 10,000 feet, which is in itself an abnormal cabin altitude to fly at, and exposes the passengers to even more oxygen depravation than what they are normally used to when they fly. (Cabin altitudes are normally in the 4,000-6000 foot range). Keep the passengers in a state of shock and pehaps panic for longer than necessary because you need to get the aeroplane to where the replacement is. Risk having someone perhaps dying as a consequence, but no matter, the aeroplane will get back to base, or

B) Land at the nearest suitable aerodrome. Panic over, passengers can breathe sea level oxygen again, and real doctors can attend to those who need attention. If someone dies on finals, you would have done the best you could.

Last edited by Wornout Rubber; 4th Feb 2008 at 11:28.
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Old 4th Feb 2008, 11:08
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Wornout Rubber,

You werent the Captain! You didnt make the decisions! You most certainly dont have all the facts!

It sounds like this incident scared you and you werent even on the aircraft. If you are that bothered about it, I suggest you refrain from flying from now on!

OSOP

P.S. Amongst other things, on the aircraft I fly, the cabin regularly reaches 8000' and has been higher so I am afraid your arguments are wearing extremely thin!
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Old 4th Feb 2008, 11:45
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On Speed on Profile

I am not talking about what you would do on your Cessna 150 flying at 8,000 feet.

This is about us big boys flying the big jets.

It would help too if you read my first sentence:

"Regarding a rapid depressurization and subsequent actions, we do not know the full details of the SQ incident, and indeed whether they suffered a rapid depressurization at all."
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Old 4th Feb 2008, 13:34
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Warnout Rubber,
Regarding a rapid depressurization and subsequent actions, we do not know the full details of the SQ incident, and indeed whether they suffered a rapid depressurization at all.
By that statement alone, you should just stop, pause and consider exactly what your opinion is before you go spouting off! Especially if you operate as one of the "big boys flying the big jets".

By the way, IMHO, trying to make your self more important by commenting on my credentials when you know nothing about me just makes you look more pathetic. I guess I better get back to my C150!


OSOP
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Old 4th Feb 2008, 16:17
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Wornout rubber,
you don't need to fly a 150 for your cabin to reach 8000'.

From the A330 FCOM:
The cabin altitude is
limited to 7350 ft for flights longer than 2.5 hours, and 8000 ft for flights shorter than 2.5 hours.
It reaches these altitudes at F410

Last edited by golfyankeesierra; 4th Feb 2008 at 17:03.
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Old 4th Feb 2008, 16:32
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Hi Wornout,

I donít know if youíve already had in your career a real situation like you described. Anyway, it is your decision and based on few details about that incident IMHO initially that crew did what was the best option in terms of safety, because we donít know how far they were from SIN, we have absolutely no idea about weather en route, in SGN, Brunei and other alternates, etc. And also we donít know if those guys decided to stay at 10,000 ft or at 8,000 ft (the same cabin altitude maintained on a B737 on FL 370) after reaching a safe altitude. In short: only hypothesis and few facts.
But Iím sure: SIA is a serious airline not a kindergarten.
Meanwhile itís time to sit back and relax waiting for more information
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Old 6th Feb 2008, 17:25
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Jesus guys take a breath.................I don't know exactly what happened on the SQ 777 that day, do you?

If the situation warranted it I see NO problems returning to SIN.

Give the guy a break.
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