How would you handle this Crew Oxygen Low situation
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I would rather do it with "PAN", not "MAYDAY". Emergency itself put stress on ATC and potentially other traffic, especially if someone happens to be in real emergency at the same time.
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You could argue that it's not an emergency once they're below 13000' if you like, but in my mind, that's splitting hairs. Scenario for you, you're at altitude and notice the lack of O2, but don't declare the mayday. Ask ATC for lower, and he says unable. Now what do you do? Mayday gives ATC the ability to move planes out of your way for the descent.
"Pan Pan, Pan Pan, ABC request descent FL__ __due crew oxygen leak"
This really is a great website. Just when you're running out of scenarios to consider Pprune throws up another one
This really is a great website. Just when you're running out of scenarios to consider Pprune throws up another one
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Oxygen Leak
Experienced a very tight situation in an RAAF Canberra enroute Cocos Island to Butterworth Malaysia in the 60s.
Detected unusual low oxy contents beyond PNR. It took a while to figure out the rate of depletion and what to do next. The Navigator was skillfull at attempting to work out a trade off between fuel burn at a survival lower altitude when Oxy depleted. The rate of Oxy leak became the significant factor and was such that it looked close to having to abandon the aircraft before being able to reach a closest airfield.
When Oxy ran out we were forced to a much lower altitude where rate of fuel useage increased considerably. Made it to Butterworth having just enough left to taxi.
I have run short of oxygen on two other occasions with one at night not being recognised until near unconsciousness. The emergency oxy system did not work. In an annoxic state I managed to stay alive by taking deep breaths and pressurising my lungs to a maximum whilst diving steeply at a Mach number close to entering an uncontrollable nose down tuck.
The body's recovery was not like that which you experience in a decompression chamber. It was a supreme effort to continue the flight to a landing and even taxying was a huge task. The next morning I awoke to a bad headache and extreme lethergy. Perhaps there was some brain damage.
Ever since I have tried to determine the minimum blood oxygen percentage which will just keep an average human conscious. It seems to be about 65 to 70 %. Does anyone out there have a more accurate figure? Climbers of Everest should know.
Detected unusual low oxy contents beyond PNR. It took a while to figure out the rate of depletion and what to do next. The Navigator was skillfull at attempting to work out a trade off between fuel burn at a survival lower altitude when Oxy depleted. The rate of Oxy leak became the significant factor and was such that it looked close to having to abandon the aircraft before being able to reach a closest airfield.
When Oxy ran out we were forced to a much lower altitude where rate of fuel useage increased considerably. Made it to Butterworth having just enough left to taxi.
I have run short of oxygen on two other occasions with one at night not being recognised until near unconsciousness. The emergency oxy system did not work. In an annoxic state I managed to stay alive by taking deep breaths and pressurising my lungs to a maximum whilst diving steeply at a Mach number close to entering an uncontrollable nose down tuck.
The body's recovery was not like that which you experience in a decompression chamber. It was a supreme effort to continue the flight to a landing and even taxying was a huge task. The next morning I awoke to a bad headache and extreme lethergy. Perhaps there was some brain damage.
Ever since I have tried to determine the minimum blood oxygen percentage which will just keep an average human conscious. It seems to be about 65 to 70 %. Does anyone out there have a more accurate figure? Climbers of Everest should know.
ALMA paper on oxygen levels
Originally Posted by Milt
Ever since I have tried to determine the minimum blood oxygen percentage which will just keep an average human conscious. It seems to be about 65 to 70 %.
Everest climbers are physiologically different from the rest of us. They find Everest Base Camp a recuperation site. For not a few of us it would be rather rapid death.
[disclosure: I'm not a pilot, but I did take an course in cardiovascular pathophysiology some years ago]
Last edited by archae86; 26th Jul 2013 at 04:03. Reason: fix punctuation typo
Originally Posted by Milt
When Oxy ran out we were forced to a much lower altitude where rate of fuel useage increased considerably. Made it to Butterworth having just enough left to taxi.
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Exactly, pure oxygen coming into contact with any kind of grease and BANG
It's not a great marriage, but takes more than 'contact'.
A CAPTAIN attended a meeting with a burnt face and without his usual well groomed waxed moustache. "What happened?" he was asked. "We lost cabin pressure", the captain explained, "so I grabbed the oxygen mask, slammed it to my face and—whoosh! my moustache caught fire"
True story, apparently, although quite a few years ago (not too many captains with waxed moustaches around any more!).
Also an incident where, I think, a military Hercules pilot's cheese sandwich caught fire as he was eating it. 100% O2 needs a great deal of respect.
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Yep you never know if the warning information is a symptom of a primary cause or a (hidden) secondary. Much better safe than sorry as it increases your chances of finding a effective solution to the problem, especially if it propagates.
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Crew O2
As a Captain, I will never criticize a fellow Captain's decision ending with safe operation.
However, I would have handled this deferentially;
The way I would have gone with this is to switch off the crew oxygen valve for a while to see if the leak was down stream the valve or up stream.
If you switch off the crew oxygen valve and the leak stops, then you know that the leak is down stream.
I would then continue the flight with the valve in close position , and i would brief my F/O that in case we have smoke or rapid decompression, we will FIRST switch the O2 valve on, put our oxygen masks on and continue with the memory items/QRH .
If you switch off the oxygen mask and leak continues, it means that the leak is up stream the valve, I would then calculate the rate of depletion and see if I can make the nearest suitable airport, if it appears that I will not, then , and only then , I would declare mayday and descend to MEA or 10000 feet.
Your rout off course can dictate a deferent course of action, flying over the Himalayas for instance, will force you to take escape rout maneuver into account.
In this case, they were over the Atlantic, terrain was not a factor so, I would have done what I said I will do.
This may sound scholastic but, its safe and economical at the same time.
Your thoughts please?
However, I would have handled this deferentially;
The way I would have gone with this is to switch off the crew oxygen valve for a while to see if the leak was down stream the valve or up stream.
If you switch off the crew oxygen valve and the leak stops, then you know that the leak is down stream.
I would then continue the flight with the valve in close position , and i would brief my F/O that in case we have smoke or rapid decompression, we will FIRST switch the O2 valve on, put our oxygen masks on and continue with the memory items/QRH .
If you switch off the oxygen mask and leak continues, it means that the leak is up stream the valve, I would then calculate the rate of depletion and see if I can make the nearest suitable airport, if it appears that I will not, then , and only then , I would declare mayday and descend to MEA or 10000 feet.
Your rout off course can dictate a deferent course of action, flying over the Himalayas for instance, will force you to take escape rout maneuver into account.
In this case, they were over the Atlantic, terrain was not a factor so, I would have done what I said I will do.
This may sound scholastic but, its safe and economical at the same time.
Your thoughts please?
I would Switch the crew oxygen sytem off initially (which you can in an Airbus330.) I would then procure an oxygen bottle from the cabin for each of the flight deck occupants, re-familiarise myself and LHS pilot with it's operation and communication facilities. Continue flight safe in the knowledge that should there be a subsequent sudden and rapid decompression (either self-induced to remove smoke or fumes, from an electrical failure or from airframe damage) that we in the flight deck have sufficient oxygen available to sustain us as we descend to a safe altitude.
ie I would replace a system, which is for emergency use only, with another. Of course this is not a dispatch condition, but nor would I treat it as an emergency, only abnormal.
I imagine that the original described scenario has lot some of it's nuances.
ie I would replace a system, which is for emergency use only, with another. Of course this is not a dispatch condition, but nor would I treat it as an emergency, only abnormal.
I imagine that the original described scenario has lot some of it's nuances.
Last edited by beardy; 26th Jul 2013 at 07:31.
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As a passenger waiting for departure in a regional aircraft from Dulles to Philadelphia, I was quite annoyed when they insisted on returning to the gate and taking a later flight because the Captain's emergency air bottle was U/S.
Especially as the flight would have remained below 12,000.
And then I remember that flight - can somebody give the ref - that flew on and on and on over the Med until it ran out of fuel....the entire crew and a considerable number of passengers unconscious to the end.
Don't mess about with lack of O2....
Especially as the flight would have remained below 12,000.
And then I remember that flight - can somebody give the ref - that flew on and on and on over the Med until it ran out of fuel....the entire crew and a considerable number of passengers unconscious to the end.
Don't mess about with lack of O2....
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And then I remember that flight - can somebody give the ref - that flew on and on and on over the Med until it ran out of fuel....the entire crew and a considerable number of passengers unconscious to the end.
Really??
The cabin portable oxy bottles are not of the same standard as the flight crew fixed masks and may not provide enough Oxygen under the ambient conditions or keep smoke out of your lungs.. Not to mention you wouldn't have goggles on the portable mask. Airbus and Boeing fit the Eros Masks for a reason in the cockpit chaps....so using the portable masks from the cabin might make you feel better before any event but will probably kill you in the end....
This crew did what I would do.
Well done to them.
The cabin portable oxy bottles are not of the same standard as the flight crew fixed masks and may not provide enough Oxygen under the ambient conditions or keep smoke out of your lungs.. Not to mention you wouldn't have goggles on the portable mask. Airbus and Boeing fit the Eros Masks for a reason in the cockpit chaps....so using the portable masks from the cabin might make you feel better before any event but will probably kill you in the end....
This crew did what I would do.
Well done to them.
Last edited by nitpicker330; 26th Jul 2013 at 08:57.
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The Oxy. was anemergency supply, on standby until it was needed in an emergency.
Therefore a PAN would have sufficed, as there would have only been an emergencyrequiring a "mayday" if there had been a failure necessitating use of the Oxy., between the time of fault and time of reaching safety. (landing, if smoke/fumes, 10K' if decompression.
bit of an over-reaction and no biscuits with the tea.
(no toasted cheese sarnie either)
@ Framer
@ Jurassic Jockey....tell them the situation? 1- expedite lower or2- have a full scale Pan/Mayday on your hands....your choice, Controller!
Therefore a PAN would have sufficed, as there would have only been an emergencyrequiring a "mayday" if there had been a failure necessitating use of the Oxy., between the time of fault and time of reaching safety. (landing, if smoke/fumes, 10K' if decompression.
bit of an over-reaction and no biscuits with the tea.
(no toasted cheese sarnie either)
@ Framer
@ Jurassic Jockey....tell them the situation? 1- expedite lower or2- have a full scale Pan/Mayday on your hands....your choice, Controller!
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There is no such thing as "declaring a PAN". 
A PAN call is just an urgent message concerning safety.
E.g.:
"PAN PAN PAN fligtxxx, we just saw a forrest fire erupt 7 nm south of yyy"
It will mean absolutely nothing concerning your priority with ATC.
A PAN call is just an urgent message concerning safety.
E.g.:
"PAN PAN PAN fligtxxx, we just saw a forrest fire erupt 7 nm south of yyy"
It will mean absolutely nothing concerning your priority with ATC.
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Framer:
"Pan Pan, Pan Pan, ABC request descent FL__ __due crew oxygen leak"
"Pan Pan, Pan Pan, ABC request descent FL__ __due crew oxygen leak"
"Negative"
-"Roger ABC, standby for descent due to other traffic"
