Emergency Air on Airplanes

It seems that commercial airline
are removing emergency oxygen from washrooms for fear of it being used as an explosive device. Another reason not to fly or just a reason not to use the washrooms in-flight?

Sorry - forgot the link:
http://m.wltx.com/national/article?a=161128&f=1348

I always hold my breath anyway. So it doesn't bother me!

Maybe someone can tell us: how quickly do we lose consciousness or becoming debilitated if the cabin loses air pressure? In other words, in an emergency will you have time to finish up & run back to your seat?

DB

In the event of sudden, catastrophic decompression at 35,000 feet, you'll have a half minute to one minute of useful conciousness. Plus factor in all the mayhem in the cabin and the stress. The pilot will be executing an emergency descent to a lower altitude so it may be hard to even stand on your feet.

Flights tend to be quite crowded these days, but I think your best bet would be to find an extra mask as close to the lavatory as possible. Obviously, any free mask and seat will probably be a middle seat.

Hmmm... how much of that time would be used just to realize that SOMETHING is happening, come to terms with the situation and decide that the right action is to go get an oxygen mask?

If you pass out - will you simply regain consciousness as soon as conditions have stabilized after the emergency descent? I would think so (and hope so!).

Hopefully you've not been tossed about too bad in the lavatory when the pilots made the dive from high altitude.

The pilots have quick-donning oxygen gear so they should be good. They practice this.

If it's truly sudden, massive decompression (why did this happen?) I think the maneuver is to roll the plane on its side and unload the wings into something like a sideways 0 g condition.
This drops the plane quickly and doesn't build up airspeed like a dive would. It's an acrobatic kind of maneuver because the emergency is very serious. Of course if there's doubt about structural integrity after the decomp then a less radical maneuver is done. So you'll be unconscious longer.

You aren't going to be returning to your seat easily during this maneuver.

Hopefully you didn't fly with a cold because your sinuses would likely be damaged in the event as well.

Wow, I've never heard of a commercial airliner pulling a manuever like that. What is it called?

By 0g, I assume it would be like riding NASA's "Vomit Comet" training aircraft that simulates 0g? Nothing better than tasting the same airline meal "twice" on a long flight!

I was on a NWA flight from Minneapolis years ago when the oxygen masks deployed due to a sensor malfunction. It probably took me 10 seconds to grasp the yellow mask and put it over my face. Looking around you had people saying, what happened, talking to each other, looking over the seats for a flight attendant. I was convinced we were about to die catastrophically so it is still one of the most memorable moments in my life. Probably half the people didn't put their masks on before the pilot came on the intercom and said there was no emergency.

there's always potential survivors, and everyone else. The great God Boeing drops an oxygen mask in your lap, put it on immediately.

I'm speculating on this somewhat because I'm not a trained airline pilot. (just a light airplane pilot, glider flight instructor, and historian of local airplane crashes - maybe a real line pilot can chime in?) The difference being that you'd be riding the plane while it's at a very high bank angle. Vomit Comet does its thing wings-level.

But I could safely say that the maneuver would be called the "sudden decompression emergency descent maneuver" - or something like it :-) (Followed by the "mass upchuck chorus")

Descending without building up excessive speed is important. High speed means an indelicate pullup could bend wings, cause high g in the cabin and you still have to bleed off the speed. And simple airspeed = airframe stress. There is a reason there is a Redline Speed (Max. Never Exceed). You also have a maximum speed for flight thru turbulence so.... getting down when it's bumpy also needs to be achievable.

Yes, it would be quite the chaotic ride down.
Better for the emergency to be slow decompression so changing altitudes briskly would do the job.

Pretty hypothetical, but would it be possible to share air, as one does in scuba emergencies, if you could not reach your own air supply? - hopefully with an attractive passenger of the opposite sex....

Each seat has its own supply. Otherwise it's not a legal seat.(there are certification requirements to carry passengers)
If your mask doesn't deploy for you, the theory is sound that you could share a mask. Good luck getting it to happen. Then again, it would give you something else to think about and work on during the crisis so that would be good.

This is like worrying about an Ostrich attack when you're at the mall.

The number of incidents of uncontrolled decompression, globally, is negligible.

Agreed Martin.

I can't fly the plane. Unless someone told me where the autopilot thingy was.

I quit worrying about stuff I can't control.

I've been told by a couple pilots that Microsoft Flight Simulator is accurate enough that a little bit of time with it you could fly a plane if you had to.
I got to fly with a guy who owned his own single prop 4 seater and he explained things to me and let me take off and fly, landing is the hardest part, getting the angle and speed just right.

"Hmmm... how much of that time would be used just to realize that SOMETHING is happening, come to terms with the situation and decide that the right action is to go get an oxygen mask?"

About as much time as it takes to realize that slamming on the brakes is a better option than slamming the accelerator to the floor when you see that speeding semi running the red light at that intersection.

As Lono said, if an oxygen masks drops in your lap, put it on.

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"I think the maneuver is to roll the plane on its side and unload the wings into something like a sideways 0 g condition. This drops the plane quickly and doesn't build up airspeed like a dive would."

I think that's called a side-slip.

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"Pretty hypothetical, but would it be possible to share air, as one does in scuba emergencies, if you could not reach your own air supply?"

Do the words 'From my cold, dead hands!' mean anything to you?

Sue

Nit picky correction: The maneuvers are similar but not the same. Side-slip doesn't unload the wings.It's the unloading that gets the plane down in a hurry.

Sideslip is used to create drag by putting the fuselage a bit sideways in the airflow. (Or as I used it- to move the passenger's head out of the way so I could see the runway on final from the back seat of the training glider)

Reconsidering- there's not a clear demarcation between where one ends and the other begins. But a side-slip is generally considered a normal flight maneuver used routinely for landing. The other is a highly radical flavor of similar control inputs.
Kind of like the difference between a racing turn on a dirt track and a bootlegger's turn on the highway (or something like that).

Current safety standards for commercial airplanes mandate that no single failure of the pressurization system can result in a loss of cabin pressure.

Modern airplanes can fly at altitudes above 40,000 feet. Certification to fly at these altitudes requires that no loss of pressure would result in the passengers being exposed to cabin altitudes above 40,000 feet for more than 1 minute. Similarly there is a long standing requirement that passengers not be exposed to cabin altitudes above 25,000 feet for more than two minutes.

This means that emergency descents must rapidly exceed 10,000 feet per minute (about 113 mph vertically). Assuming the pilots can maneuver aggressively enough to meet the regulatory requirements you would most likely pass out within 30 to 60 seconds and assuming no other injuries, you would regain consciousness after passing below 10,000 feet, say in 2 to 3 minutes. Not sure if this is enough time to cause significant damage other than from the rapid depressurization.

Even with 100% oxygen there is not enough pressure/density above 30,000 feet for most people to sustain consciousness. Pilot oxygen masks are sealed to maintain pressure. Passenger oxygen masks don't seal enough to maintain pressure but having a higher concentration of oxygen at even much lower pressures can help a lot.

-Eric