737 rapid decompression

[juan23]

Accident: Aerolinea Sky B732 near Concepcion on Oct 9th 2009, rapid decompression


A Aerolínea Sky Boeing 737-200, flight H2-20 from Puerto Montt to Santiago (Chile), was enroute about halfway into the 500nm journey, when the airplane experienced a rapid decompression prompting the crew to initiate an emergency descent. The crew subsequently diverted to Concepcion's (Chile) Carriel Sur Airport, where the airplane landed safely.

Several passengers suffered from nose bleeding as result of the decompression.

The airline reported, that a hole opened in the airplane's pressure hull causing the decompression however no danger existed for the airplane or the occupants.

I wanna picture

[canair67]

Where in the Hull? Curious. And yes, pics would be a good thing. I cannot find any.

[WILCO737]

Good that everybody is ok.

A rapid decompression is for sure very uncomfortable. I only did it several times in the simulator...
You need to get down to 10,000 feet ASAP so that everybody can breath normally.

wilco737

[474218]

Good that everybody is ok.

A rapid decompression is for sure very uncomfortable. I only did it several times in the simulator...
You need to get down to 10,000 feet ASAP so that everybody can breath normally.

wilco737

You have a pressurized Sim?

[WILCO737]

You have a pressurized Sim?

No, we don't. But the procedure how it is done is quite impressive. A nice rate of descent you can get out of the airplane which you wouldn't use during normal operation. And we saw a lot of videos and pictures and experience reports of these incidents and all are pretty impressive.

wilco737

[TeeVee]

so in general, in a decompression emergency, what is the descent rate? is it different for different a/c? or is there a standard x feet per minute descent?

[WILCO737]

so in general, in a decompression emergency, what is the descent rate? is it different for different a/c? or is there a standard x feet per minute descent?

It is differnt for every airplane as every airplane has different performance capabilities.
On the 737 we had something around 4000+ ft/min on the MD11F I saw more than 6000 ft/min for a while.
During an emergency descent you start at high altitide, throttles to idle and speedbrake extended and going to Vmo/ Mmo (max speed), which initially gives you a huge rate of descend. The speed will be traded into descend rate. Once at Vmo/ Mmo you stay at that speed and you descend to roughly 10,000 feet quickly as the oxygen for the passengers is limited to 10 minutes.
If you have structural damage (maybe the cause of the decompression), then you have to observe vibrations if you even accelerate to Vmo/ Mmo. So the stress to the fuselage get get even higher if you fly faster, so then you stay at that speed where the decompression happened or even reduce it slightly that the stress for the fuselage will not get any higher.

wilco737

[EconomyClass]

Is the main problem that the oxygen content of the cabin air drops too far for humans to survive? But if the masks drop, are they then supplied with very few minutes worth of adequate oxygen? I suppose on these flights with hundreds of passengers, that could very well be the case.

Which reminds me of another question. Why was it dangerous to carry oxygen tanks if every plane is fitted with oxygen tanks for depressurization situations?

[TheRealAncientMarine]

Is the main problem that the oxygen content of the cabin air drops too far for humans to survive? But if the masks drop, are they then supplied with very few minutes worth of adequate oxygen? I suppose on these flights with hundreds of passengers, that could very well be the case.

Which reminds me of another question. Why was it dangerous to carry oxygen tanks if every plane is fitted with oxygen tanks for depressurization situations?

They have pressurized oxygen tanks in airplanes? That's scary.
Per

[WILCO737]

Is the main problem that the oxygen content of the cabin air drops too far for humans to survive? But if the masks drop, are they then supplied with very few minutes worth of adequate oxygen? I suppose on these flights with hundreds of passengers, that could very well be the case.

Which reminds me of another question. Why was it dangerous to carry oxygen tanks if every plane is fitted with oxygen tanks for depressurization situations?

We don't have oxygen tanks for passengers on board. On the overhead panel where the oxygen masks are stowed you have generators where oxygen is "produced" via a chemical reaction... Watch out: it will get above your head!

The oxygen masks delivers 100% oxygen, but it is mixed with the cabin air around you, so you breath oxygen enriched cabin air. That is enough to get enough oxygen and stay concious.
During that time we cockpit crew start the emergency descend which is rather uncomfortable, but it is necessary to get down asap. We in the cockpit have full face oxygen masks and breath 100% oxygen.
When reached abot 10.000 feet you can breath normally again as the air contains enough oxygen.

wilco737

[Highkeas]

We don't have oxygen tanks for passengers on board. On the overhead panel where the oxygen masks are stowed you have generators where oxygen is "produced" via a chemical reaction... Watch out: it will get above your head!

The oxygen masks delivers 100% oxygen, but it is mixed with the cabin air around you, so you breath oxygen enriched cabin air. That is enough to get enough oxygen and stay concious.
During that time we cockpit crew start the emergency descend which is rather uncomfortable, but it is necessary to get down asap. We in the cockpit have full face oxygen masks and breath 100% oxygen.
When reached abot 10.000 feet you can breath normally again as the air contains enough oxygen.

wilco737

Here is a pretty good description of these oxygen generators:

http://en.wikipedia.org/wiki/Chemical_oxygen_generator

[juan23]

Anybody remember this?

737 rapid decompression
Your off topic people!

Gabriel, its your part of the planet get me a picture.......................please

[SYDCBRWOD]

Anybody remember this?

737 rapid decompression
Your off topic people!

Gabriel, its your part of the planet get me a picture.......................please

Juan, I realise that this gets in the way of your picture collecting, but is there just the slightest chance that on board oxygen for Pax is maybe slightly related to 737 Rapid Decompression?

If you are looking for off-topic I'm sure we can find some better examples so you can compare. Anyone care to demonstrate?

[SYDCBRWOD]

We don't have oxygen tanks for passengers on board.

wilco737

Must be different solutions for different airliners - the Qantas 747 that suffered a decompression did so because (ironically) one of the oxygen bottles punched it way out through the hull. So at least some airliners seem to use compressed O2?

[WILCO737]

Must be different solutions for different airliners - the Qantas 747 that suffered a decompression did so because (ironically) one of the oxygen bottles punched it way out through the hull. So at least some airliners seem to use compressed O2?

Yes, that is true. Different airlines, different airplane types, different certification. etc etc.

wilco737