AIRBUS cockpit oxygen at zero

[alphaflare]

hi all,
Question for all busdrivers;suppose during flight from A to B (3hours flight time) after 1 hour of flight you notice that your cockpit oxygen is at zero,what to do ?
appreciate any feedback,experience; many thanks.

[Iceman49]

Think I would descend to altitude where O2 is not required.

[dixi188]

Our Airbuses (A300) have 2 flight deck oxygen bottles with a crossfeed system so that 3 masks are fed from one bottle and 2 masks from the other.
If one bottle had leaked to empty then selecting crossfeed might empty the other if the leak was downstream of the selector valve. We also have a portable bottle on the flight deck so, if after selecting crossfeed, a leak was identified, then I would go back to normal feed and have the portable set available should it be required.

I'm not sure what the later Airbuses have.

Hope this helps.

[hetfield]

Think I would descend to altitude where O2 is not required.

What about possible smoke..?

[Old Smokey]

This topic came up on PPRuNe some years ago, not Airbus specific, but covering all types. The general consensus amongst Prooners after quite sensible discussion went something like this -

Descend to 25,000 feet. At 25,000 feet Time of Useful Consciousness is 4 minutes, more than enough to descend rapidly to 10,000 feet following depressurisation. (It is also why aircraft not operating above 25,000 feet do not require a passenger Oxygen system).

At 25,000 feet, evaluate your range capability, and continue to destination or divert to Alternate as necessary. Don't forget that all flights must carry sufficient fuel for diversion to Alternate at 10,000 feet if depressurised, so flight at 25,000 feet will be well possible.

Where you're in trouble is crossing extended areas of high terrain with high MEAs, Afghanistan, Iran etc., where you might have to spend some time at around 18-19,000 feet, in which case carrying 2 of the portable Oxygen bottles in the cockpit is advised.

I've actually had a total loss of cockpit oxygen, and I chose to descend to F/L 250, if memory serves me correctly, 411A reported a similar experience.

Oh Hetfield, why did you have to bring up smoke? Screws up all the theories

Regards,

Old Smokey

[Spooky 2]

Many years ago on a B727 flight from KIAD to KSLC with a FAA Inspector on the jump seat....setting the picture here. The Captain noticed that the crew O2 was at zero, The gauge is actually on the FE upper panel as I recall. The Captain remained quiet as he mulled over his options. Just about the ame time the FAA guy decided he needed to use the lav and excused himself from the flight deck. A quick check dtermined that the culpirt in the debacle was the F/O's regulator which had been turned on somehow. Quick thinking the crew turned on the regulator at the FAA's jump seat and of course turned off the F/O's position. A few minutes after the FAA inspector returned to the flight deck the S/O verbalized the zero O2 condition wherein the Captain announced "everyone check their regulators". Well obviously the FAA guy was aghast to find he had drained the O2 system, The Capt. quickly asked him if they should land at Denver, to which the FAA said words to the effect, "Oh please don't do that" as I'm sure he could see his future as a FAA inspector going down the drain in a nano second. Don't recall if they descended to a lower or not.

True story and since most if not all involved haved passed on, I think it's worth telling.

[MD11Engineer]

We had a 737 for a while, on which we were servicing the crew oxygen cylinder everyday. We did leak checks, but couldn't find any leak, until one of us noticed that the F/O regulator was set to "Emergency" and thus slowly bleeding the oxygen system.
On most crew oxygen masks in use today there are three positions, usually named "Emergency", "100%" and "Normal".
In "Emergency" the mask reglator provides a steady stream of oxygen, e.g. for clearing smoke from the mask, in "100%" the mask delivers pure oxygen on demand, e.g. the pilot has to actively inhale to open the demand valve, while in "Normal" the mask mixes pure oxygen on demand with ambient air.
When stowed the mask regulator is supposed to be sent in the center "100%" position to prevent leaking the oxygen supply.
After we informed the crews about the proper operation of the mask regulator, the excessive use of oxygen stopped.

[mcdhu]

I'm with Hetfield on this one! Embarrassing though it is, surely you should land as soon is 'reasonable' (a good aviation word) to replace the bottle. You would look very silly - and probably quite dead - if you had a smoke scenario with no crew O2.

Cheers
mcdhu

[xxqTpxx]

i would agree as well! as the leagal requirement states the lowest alt is 15000ft without oxygen if the flight is mless than 1/2hour(not exactly sure).but you would rather want to land asap! cos if you have smoke time of useful concious is all until you get that mask on!!! and smoke that can exist are mostly toxic as well

[fireflybob]

What about getting the theraputic oxygen from the cabin onto the flightdeck?

Spooky, that's got to be one of the best postings I've seen on Pprune for a while - full marks for initiative!

[hetfield]

@spooky

Good one!

Very smart

(Have flown 727 as a F/E and F/O, lovely plane)

Bye

[PENKO]

Firefly, I thought about the therapeutic oxygen from the cabin. However if I am not mistaken, above a certain cruising altitude you need 'quick donning masks'.

Spooky's story will indeed stick to my mind

[Office Pest]

Well I had this very situation a few years ago on an A-320. We were in the cruise with quite a way to destination when it was noticed that the crew oxygen bottle quantity was very low. As I understood it the only masks that provide effective protection against smoke are our quick donning masks and of course the one smoke hood on the flightdeck. It was decided between us to divert to a company base en-route to get it seen to by an engineer. The smoke part of this equation was the real concern to me.

Best Regards,
Office Pest

[backofthedrag]

Theraputic oxygen or the smoke hood may save your bacon , but proper cross cockpit communication is not catered for - nor would I assume your Company SOPs go this route.
To be kosher you have to divert .
If enough fuel fuel and continuing at below 10000 ft may be an extreme option , but not likely in the early stages of a long jet flight.
Follow SOPs.

[Wizofoz]

Don't forget that all flights must carry sufficient fuel for diversion to Alternate at 10,000 feet if depressurised,

Slight TD here, but under which regulations is the above true? (For info, not the ones I fly under (UAE GCAA))

[Old Smokey]

I don't have the regulations beside me as I reply Wizofoz, but are you implying that there are jurisdictions which allow NO consideration for depressurisation at the most Critical Point between Suitable Airports for RPT operations?

Regards,

Old Smokey

[Wizofoz]

That wasn't the statement, Smokey. The question was in regard to destination alternate. Where I'm flying fuel for alternate is calculated at optimum cruise altitude for the planned route. CP (dep) is a different matter.

[PENKO]

Destination alternate? What use is that?

Surely your company has a bit of text that says 'when you depressurize and descend to 10000' at any point on the route, you must be able to make it to an adequate alternate with sufficient fuel.' Or are you expected to ditch?

[Wizofoz]

Penko,

Yes, but that airport can be the destination. If the destination is forcast as being above suitable weather, there is no requirement to have sufficient fuel to approach at the destination, miss and THEN go to alternate at 10 000'.

Missing out on the destination and then depressurising is assumed to be a remote possibility.