I was watching a documentary " A day in the life" covering an airline pilot. He was working for Candian airlines back in 1993, and it surprised to know that there was a regulation to put oxygen mask on whenever the other pilot left the cockpit at cruise altitude. It got me thinking :

1- Was it a universal regulation or only applied in Canada?
2- Is it still in effect?
3- Was it an Airline policy or a regulation by the aviation agency and other airlines had to adhere to it?

Followed is the link to the documentary, the particular part is at 27:07 mins
https://youtu.be/X-hLxIdD_IA?t=27m7s

This is/was not uncommon in some/all places, especially as you get up in altitude where time of useful consciousness is under 30 seconds. At 30000 feet you have "plenty" of time. At 40000, not so much.

However (where I work) the requirement to wear a mask is waived if the mask is of the quick-donning type. We use the exact same mask model as the one in the video, and it is indeed classified as quick-donning. Then again I haven't worked since 1993 so I don't know what the requirement was at the time.

Not a requirement, but good airmanship is ensuring the mask compartment cover is never obstructed by a meal tray or the like.

Side note: There is a requirement for one crewmember to wear the mask when taking off from a high-altitude airport.

I can't comment on Canada specifically but for what it's worth the US regulations call for one pilot to utilize oxygen when the other pilot leaves the flight deck anytime the aircraft is above FL 250. Also, there is a requirement for one pilot to be on oxygen anytime the aircraft is above FL 410.

Unfortunately the US regulations don't offer any relief for quick donning masks.

SaveFerris wrote:

I can't comment on Canada specifically but for what it's worth the US regulations call for one pilot to utilize oxygen when the other pilot leaves the flight deck anytime the aircraft is above FL 250. Also, there is a requirement for one pilot to be on oxygen anytime the aircraft is above FL 410.

Unfortunately the US regulations don't offer any relief for quick donning masks.

While I'm certainly happy I don't have to don the Alien Facehugger outside the sim, I must confess that a quick read of a time of consciousness vs altitude table is rather sobering. At FL410-430, I have 10-15 seconds to get the mask on. That's more than enough time in the sim, but in real life there's probably a bit of a startle factor.

And that doesn't even count the fact that at those altitudes the differential pressure will actually be extracting oxygen out of your bloodstream unless air is being pumped into your lungs by the mask. Good times.

The fact is the cabin, in the certification test, doesn't instantaneously get to anything like actual aircraft altitude. At F510, the test is to open a hole equivalent to a window, apply a reaction time and begin the emer descent- the plane and cabin "meet" below F250. The actual leak rate is quite low-1,500-2,000 fpm.

GF

GalaxyFlyer wrote:

The fact is the cabin, in the certification test, doesn't instantaneously get to anything like actual aircraft altitude. At F510, the test is to open a hole equivalent to a window, apply a reaction time and begin the emer descent- the plane and cabin "meet" below F250. The actual leak rate is quite low-1,500-2,000 fpm.

GF

A window is one thing. A cargo door departing is another.

AFAIK if you lose a window the packs can still maintain some pressure, so you'll have a moderate cabin altitude increase. I wouldn't call 1500-2000fpm a low rate of climb, though.

If you lose a cargo door, things will be a bit more dramatic. No way the packs can handle that.

In any case explosive decompression is not the likeliest scenario for a pressurisation fault. More likely a pack controller is malfunctioning or an outflow valve is stuck open, in which case things are much slower.

SaveFerris wrote:

I can't comment on Canada specifically but for what it's worth the US regulations call for one pilot to utilize oxygen when the other pilot leaves the flight deck anytime the aircraft is above FL 250. Also, there is a requirement for one pilot to be on oxygen anytime the aircraft is above FL 410.

Unfortunately the US regulations don't offer any relief for quick donning masks.

Not having to wear the mask above 250 is the relief for quick donning masks in the US... if they weren't quick donning masks, one pilot would have to be on oxygen above 250 for 121, 350 for part 91. FAR121.333

It's often said, and I concur, that these O2 requirements are the most violated of all the regulations. If you've ever worn a quick donning style mask you will know why. If you haven't, it's hell.

Word on the street is a European Ramp check (SAFA) after an Atlantic crossing might include a look at your ship O2 level. If still near 100% full then someone wasn't using the O2 as prescribed. Whoops.

26point2 wrote:

It's often said, and I concur, that these O2 requirements are the most violated of all the regulations. If you've ever worn a quick donning style mask you will know why. If you haven't, it's hell.

Word on the street is a European Ramp check (SAFA) after an Atlantic crossing might include a look at your ship O2 level. If still near 100% full then someone wasn't using the O2 as prescribed. Whoops.

While I agree with your first paragraph, the second sounds like a BS type story. As far as I know, there is no requirement for the crewmember who puts the mask on to keep it in the 100% O2 mode. The regulator supplies very little oxygen mix when the cabin altitude is around 8000 ft. I doubt it makes much of a dent in the gauge even if done several times at normal cabin altitudes. Now if the pilot(s) did go 100% on the dilution lever/switch to ease a headache or something, then yes it could cut into the supply.

I am sure I read somewhere that a 747 is rated for up to 3 windows blown out and can maintain almost full pressurization by closing off the cabin outlet valves. The open windows are now your new cabin outlet valves!!

RetiredWeasel wrote:

26point2 wrote:

It's often said, and I concur, that these O2 requirements are the most violated of all the regulations. If you've ever worn a quick donning style mask you will know why. If you haven't, it's hell.

Word on the street is a European Ramp check (SAFA) after an Atlantic crossing might include a look at your ship O2 level. If still near 100% full then someone wasn't using the O2 as prescribed. Whoops.

While I agree with your first paragraph, the second sounds like a BS type story. As far as I know, there is no requirement for the crewmember who puts the mask on to keep it in the 100% O2 mode. The regulator supplies very little oxygen mix when the cabin altitude is around 8000 ft. I doubt it makes much of a dent in the gauge even if done several times at normal cabin altitudes. Now if the pilot(s) did go 100% on the dilution lever/switch to ease a headache or something, then yes it could cut into the supply.

I agree. Adding to your point about small amount dispensed, how would the checker know what the oxygen tank pressure was on departure?

Starlionblue wrote:

Side note: There is a requirement for one crewmember to wear the mask when taking off from a high-altitude airport.

Thank you, is a 6900 ft high airport considered high-altitude?

sadiqutp wrote:

Starlionblue wrote:

Side note: There is a requirement for one crewmember to wear the mask when taking off from a high-altitude airport.

Thank you, is a 6900 ft high airport considered high-altitude?

I think it is 8000ft and above in our manuals.

Starlionblue wrote:

Then again I haven't worked since 1993 so I don't know what the requirement was at the time.

Haven't worked since 1993, or wasn't working in 1993? If you retired in 1993 and are still in the Danger Zone, you are one cool dude.

Hang on...in the US one pilot at cruise must wear a mask? In all the years I have been a passenger and thanked the flight deck crew member that was wishing us well after arrival, I do not remember seeing any "creases" on ANY face from prolonged use of a mask.....

bhill wrote:

Hang on...in the US one pilot at cruise must wear a mask? In all the years I have been a passenger and thanked the flight deck crew member that was wishing us well after arrival, I do not remember seeing any "creases" on ANY face from prolonged use of a mask.....

Masks don't have to be worn if they are quick donning, which pretty much all modern oxygen masks are.

rjsampson wrote:

Starlionblue wrote:

Then again I haven't worked since 1993 so I don't know what the requirement was at the time.

Haven't worked since 1993, or wasn't working in 1993? If you retired in 1993 and are still in the Danger Zone, you are one cool dude.

Haha oops! I was not working as a pilot in 1993, or in 2003. I am working now.

rjsampson wrote:

Starlionblue wrote:

Then again I haven't worked since 1993 so I don't know what the requirement was at the time.

Haven't worked since 1993, or wasn't working in 1993? If you retired in 1993 and are still in the Danger Zone, you are one cool dude.

If his a.net avatar is any depiction of his coolness, then he's pretty damn cool! And always in the Danger Zone.

bhill wrote:

Hang on...in the US one pilot at cruise must wear a mask? In all the years I have been a passenger and thanked the flight deck crew member that was wishing us well after arrival, I do not remember seeing any "creases" on ANY face from prolonged use of a mask.....

Please refer to the posts above. There are certain exceptions to the rules.