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Landflap
13th Jul 2019, 10:42
Sorry to be a lazy sod but thought I would get a fast answer here for the pub later. Flight Deck Crew Oxy, Boeings. Once on and breathing away, how long will it last ? (one user). Cheers.

harrryw
13th Jul 2019, 11:28
737 Emergency Equipment (http://www.b737.org.uk/emergency_equipment.htm#Flight_Crew_Oxygen) may help
but that does not seem to take into account o2 for other crew in decompression descent.

Sidestick_n_Rudder
13th Jul 2019, 11:38
Minimum of 2 hours, or whatever required for decompression over high terrain.

Cheere,

SnR

Tomaski
13th Jul 2019, 12:16
Sorry to be a lazy sod but thought I would get a fast answer here for the pub later. Flight Deck Crew Oxy, Boeings. Once on and breathing away, how long will it last ? (one user). Cheers.

To many variables to answer. What is the pressure? Bottle temp? Altitude? 100% or normal? Or are you looking for a minimum limit?

Landflap
14th Jul 2019, 11:02
Thanks fellas. Strange that over years, a time available figure has not stuck in my fading brain. Yeah, we know about cabin and the 14 minute figure stuck but whereas the location of the FD bottle, pressure, pressure figure that triggers the crew Oxy Qty low etc all retained after years of being asked the same questions in the brain teasers before stepping in to the sim, this damned time available is annoying me. Pub discussion arose out of the MH incident where it is rumoured that the Captain initiated a decompression but remained on crew Oxy in the FD for some considerable time while he wandered about before ditching. I was asked how long could one stay on crew oxy ?...................Blank.......................street cred out the bloody window !

Thanks harrywh. I did attempt a look at various crew manual stuff on the net but got very depressed looking at the CBT example. Reminded me of the hateful days of sitting in a CBT with a very patronising sound track from an out of work Hollywood film extra , still not referring to sustain time on crew oxy. Oh & my own manuals were lost in a Garage fire years ago.

Very good mate, non-smoker, told a great pub story of how he was subjected to a chain-smoker, after smoking on the FD was banned, aggressively determining that he would chain-smoke all the way to Manilla (about 8 hrs) ! Matey donned the crew oxy mask, established comms & said ; " Well, if you are going to do that, I'll do this all the way to Manilla ". I did wonder, even then, if the oxy would last that long.

That's all. Back to the pub & I'm buying !

birdspeed
19th Jul 2019, 09:27
In last years Malaysian report it says that the crew O2 system could supply O2 for one person for 27hrs at 36000ft. Malaysian Airlines had 2 bottles, serviced to 1800psi fitted, whereas most airlines just have one.

But personally, I think the crew bottle is the root cause for 370 going missing. It is the best/only mechanical failure scenario that could explain how it went missing. A bottle rupture could potentially cause— decompression, extensive electrical failures, crew incapacitation,autopilot/autothrottle failure all in an instant. The pilots made the first turn but never accomplished the emergency descent before becoming hypoxic.

Hope you find this info useful in your pub discussions!