Decompression in 737

[olh]

Hypothetical:
- you're on a 03:00 hour + flight ( app. 1400nm ),
- fully loaded,
- 00:35 min after DEP you decompress,
- masks deployes,
- rapid descent carried out down to 140 - 160,
- cabin reset,
- climb to a calculated, optimal cruise level for fuel available and the distance,
- continue towards filed destination,
- could the a/c do this and comply with ops procedures and regulation?
Appreciate input.
Harald

[FlingWingKing]

Extended Range Operations with Two-engined Aeroplanes (ETOPS) require an aircraft to have an alternate within 2hrs flying time during any part of an ETOPS sector. Fuel requirements will include fuel for the worst case scenario, ie decompression with two engines operating. You give too little information to give you a definite answer on your scenario.

[FlingWingKing]

Must aggree with rhood. Passenger oxygen is not pure oxygen, but oxygen generators, which once activated, will flow for 12min and can not be shut off.

[olh]

No ETOPS on this one right? The flight is from Eastern Spain to Western Norway. And, could it make destination at below F250? What other info is required?

[Pilot Pete]

And, could it make destination at below F250? What other info is required? What has 'below FL250' got to do with anything? You decompress and the masks deploy. You descend to MFA or 10,000ft, whichever is the higher. If above 10,000ft you need to get to an area where the MFA is below 10,000ft pretty quick. As mentioned above, once the pax oxygen runs out they have to be able to breath without it, hence descent below 10,000ft is required. You can't keep going at FL250 or they will all die.
So the question is really, how far can/ should you go at 10,000ft or less? After a decompression I think landing somewhere not too far away with good ground facilities would be a very wise consideration. Remember you will have potentially old and infirm passengers as well as your fit 20-30 year olds. Just think of the possible shock that a decompression and emergency descent may have on such infirm passengers. You would need plenty of good feedback from the cabin crew to even contemplate continuing beyond a suitable enroute airport. Perhaps if you had just departed your own country, then a turn back to your own shores might be a good idea, or to get out of a country with less than 'desirable' facilities, but I personally would be thinking where I was going to land rather than how far could I get in an aircraft in this condition, with the associated possible pax health problems.
Again though, no hard and fast rule and it's down to what happens, how you decompressed, where you are, what's around you (airport and facilities wise), terrain issues, weather issues, fuel and range capability, political situation (in certain countries), proximity to hospital facilities (potentially), and pax/ crew welfare issues once landed. I am sure there are more. The point is just because it is possible to do something doesn't necessarily mean it is desirable to do it.

PP

[quickturnaround]

Once you have made the rapid descend to 10000ft, there is no chance of climbing back since the pax O2 generators were activated.

But for ETOPS ops you are catered for cruising on N-1 eng at 10000 to reach your ETOPS alternate...

Unfortunately, your senario happend once in a mayor Airline after the crew restored the pressurization problem and climbed back to cruise alt, even after masks being deployed, now that was an incident!!!!

Fly safely QTA..

[jondc9]

some older planes have regular oxygen tanks which, depending on passenger load, can last quite awhile.

I agree that the plane in this case should maintain an altitude consistent with MEA/MORA and low enough that you won't need oxygen if the event happens again.



isn't it interesting that newer planes have less options than the older ones?

we used to have a nice oxygen/vs passengers chart which would allow in some cases continued flight at higher levels (though we would have descended if pressurization were lost).


j

[flufdriver]

iondc9; it is not interesting that newer aircraft have less "options" then older ones. They are deliberately designed that way in the interest of profitability and low airfares!

The box in which we operate our metal tubes (which were constructed by the lowest bidder) these days, is quite a lot tighter then it used to be.

Now think ahead and imagine what this whole business is going to be like without an actual Pilot on board.

It is now time for someone from the "we-can-fly-to-the-Moon-on-autopilot" brigade to speak up.

fluf

[jondc9]

fluffdriver

I agree with you...indeed every post I have made has the spirit that CHEAPER IS NOT BETTER.

[A V 8]

What has 'below FL250' got to do with anything? You decompress and the masks deploy. You descend to MFA or 10,000ft, whichever is the higher. If above 10,000ft you need to get to an area where the MFA is below 10,000ft pretty quick. As mentioned above, once the pax oxygen runs out they have to be able to breath without it, hence descent below 10,000ft is required. You can't keep going at FL250 or they will all die.


Do commercial pilots undergo decompression training during their pilot training?

I have experienced 25 000' in a decompression chamber, and despite pre-breathing 100% O2 for 30 mins beforehand, I was very close to unconsciousness after 2 minutes.

It was a great experience though. I would highly recommend it if you ever get the chance. It also teaches you to recognise the symptoms of the onset of hypoxia.

[The Real Slim Shady]

Passenger oxygen is not pure oxygen, but oxygen generators, which once activated, will flow for 12min and can not be shut off.

The 12 mins is at 10,000ft. The higher the cabin is......the shorter the time.

All to do with the pressure in the cabin vs the pressure from the mask.