A q about oxygen masks

[Pollywaffle]

When the safety announcements occur, they typically tell you a mask will drop from the ceiling and that you should pull it towards you. My question is how hard do you pull? Wikipedia (the source of all truth ) tells me "To operate on all aircraft...they must be pulled sharply toward the passenger who needs it to un-clip the flow pin and start the process of transporting the oxygen to the passenger."

Can you pull too much and detach it? And this flow pin that Wikipedia talks about - is it visible?

Now, don't laugh, but this has seriously occupied my time on recent plane trips. Enquiring minds want to know...

 

[lovestotravel]

If you pull too hard it'll fall off............

 

[Fruitcake]

Can you pull too much and detach it?

Apparently you can. I don't have the books on hand at the moment but in one of the accidents covered in Macarthur Jobs excellent Air Disaster series, pax got a bit excited about tugging on their masks and several managed to pull the oxygen generators out of the ceiling. Which left them with 250+ degree celsius chunks of metal sitting in their laps.

 

[under the radar]

mask drops from above..all clumped together (that's where all the 'pins' are) close to the ceiling unit...the action of just pulling down a mask will release from pin and activate oxy..the actual oxy tube from ceiling to mask is quite generous (about 1metre) as it needs to be long enough to reach a small child sitting in seat and/or others in your row..you would need to KEEP pulling until tube is stretched to limit, to actually dislodge/break anything..as a side note..in the past, during the safety demo F/As would pull the demo mask so the oxy tube was tight..which passengers interpreted as you MUST keep pulling mask tube to a tight position.(which is incorrect) ...nowadays when F/As do demo they just (SHOULD) gently pull down mask without such force/tightness...(at least,2yrs ago, QF instructed F/As to alter their physical oxy demo to reflect this) i won't enter into a discussion of how badly SOME QF F/As STILL perform the demo :shock:

 

[anat0l]

The way I understand it is that when the masks drop, they are too far above to be used directly (not that you could), hence the need to pull them down. The slack in the pin line is small enough such that any pull of reasonable length will cause the pin to dislodge.

Similarly if you pull the mask lightly, you'll encounter resistance and can't get the mask down to you, so you simply pull firmly enough to get the mask down, dislodging the activation pin in the process. A bit like picking fruit off a tree, so to speak.

At least, this is how I see it.

 

[ChrisFlyer]

I should also mention that many of the oxygen mask clusters contain an extra mask - which the crew use when walking through the cabin without an oxygen bottle (is it called monkey swinging?). Even if you break one mask, you could always use the extra one if absolutely necessary.

 

[NM]

If you pull too hard it'll fall off............

That's what my mother always told me

 

[Hvr]

If you pull too hard it'll fall off............

I'm more concerned about going blind. :shock:

 

[Flying Fox]

Maybe we should direct this question to Annie17?

She recently did this exact thing on QF974.

 

[samh004]

Maybe we should direct this question to Annie17?

She recently did this exact thing on QF974.

I was thinking that as soon as I saw the thread title!

 

[milehighclub]

I should also mention that many of the oxygen mask clusters contain an extra mask - which the crew use when walking through the cabin without an oxygen bottle (is it called monkey swinging?). Even if you break one mask, you could always use the extra one if absolutely necessary.

I've never been trained to do that although the extra masks can be used for lap children or cabin crew in the cabin who would have to just grab one and wedge somewhere (as we are trained to do).

Before the QF30 crew then had to go get a portable oxygen bottle and carry follow up duties however after the QF30 it was noted by most crew that it wasn't actually required as most crew felt fine. Now it is up to the individual crew member if they wish to continue on oxygen.

I've pulled down on the mask multiple times but on the 747/A380 where the oxygen comes from a tank. You really are just pulling a pin to start the flow (and it only flows to the mask you pull) and doesn't require much force. On the 737/767/A330 pulling any masks starts a chemical oxygen generator and will supply oxygen to all masks in that unit. It probably requires a bit more of a pull.

 

[straitman]

Before the QF30 crew then had to go get a portable oxygen bottle and carry follow up duties however after the QF30 it was noted by most crew that it wasn't actually required as most crew felt fine. Now it is up to the individual crew member if they wish to continue on oxygen.

This is a fairly dangerous practice IMHO as the effects of oxygen deprivation are totally insidious. One thinks they are doing fine when they may really be off in La La land.

 

[Boris spatsky]

This is a fairly dangerous practice IMHO as the effects of oxygen deprivation are totally insidious. One thinks they are doing fine when they may really be off in La La land.

I am with straitman on this. One of the symptoms if hypoxia can be feeling euphoric - an individual is the worst judge of their own hypoxia - only sensible option is to go on oxy.

 

[oz_mark]

This is a fairly dangerous practice IMHO as the effects of oxygen deprivation are totally insidious. One thinks they are doing fine when they may really be off in La La land.

But isn't the whole point of getting down to 10, 000 feet is to allow you to breathe normally. The oxygen masks used by passengers on some aircraft isn't going to last much this point anyway.

 

[straitman]

But isn't the whole point of getting down to 10, 000 feet is to allow you to breathe normally. The oxygen masks used by passengers on some aircraft isn't going to last much this point anyway.

Agreed but the implication in post #11 is that it is discretionary above 10,000ft. That is where the problem lies. 10,000 ft and below is not an issue other than night vision is reduced and that should not be a problem in this situation.

 

[Pollywaffle]

Thanks, everyone.

I did manage to find a picture online of the masks, so I understand the pin concept. It would be helpful to understand that you only need to pull enough for the pin to be removed.

If you pull too hard it'll fall off............

That's what my mother always told me

I'm more concerned about going blind. :shock:

I knew it! And there I was last night editing my question several times so to avoid such comments. LOL

Maybe we should direct this question to Annie17?

She recently did this exact thing on QF974.

I'm sorry but I don't know who Annie is.

 

[oz_mark]

Agreed but the implication in post #11 is that it is discretionary above 10,000ft. That is where the problem lies. 10,000 ft and below is not an issue other than night vision is reduced and that should not be a problem in this situation.

Hmm. My reading of the post was that it was referring to the period after the descent. During descent they'd just be using whatever was available.

 

[ftm]

This is a fairly dangerous practice IMHO as the effects of oxygen deprivation are totally insidious. One thinks they are doing fine when they may really be off in La La land.

Cabin Crew aren't released until the cabin altitude is at or below 14,000ft. In most cases the descent would be taken to 10,000ft (which is when the pilots can come off oxy) unless terrain or fuel required the higher. Crew aren't walking around the cabin without oxy at high altitudes.

 

[straitman]

Cabin Crew aren't released until the cabin altitude is at or below 14,000ft. In most cases the descent would be taken to 10,000ft (which is when the pilots can come off oxy) unless terrain or fuel required the higher. Crew aren't walking around the cabin without oxy at high altitudes.

That is logical and common sense. I was purely commenting on post #11 which I interpreted as cabin crew coming off oxygen earlier that that.

 

[milehighclub]

My fault for not clarifying clearly. This is after the captain releases the cabin crew for follow up duties. The aircraft at this point should be 10,000ft or under. Prior to that the crew will don the nearest mask and wedge.

If crew didn't have oxygen above that, and in a explosive decompression at 40,000ft, you would last about 15 seconds before passing out.