135 O2 Requirements in the Fractional World
 

Question for you folks in the fractional biz operating under 135: The way I read 135.89(b)(3), the mask is required above 350 even if both pilots are in their seats. Seeing that these modern jets fly way above that, is that really done or do your op specs let you off the hook?

You are correct. On 135 flights, one pilot must wear the mask above FL350. OpSpecs do not give any relief.

So best thing to do is plead ignorance and say you thought it was Part 91(k) 'coz we all know we have a longer time of useful consciousness under Part 91 than 135!!
Most retarded inconsistent rule in the regs.

In all seriousness, does anybody actually don their mask above 350?

I know I comply. Many of our passengers know the rules. I'd hate to do the carpet dance because a passenger complained. Remember, there's no cockpit door.

It's the rule isn't it?

Why wouldn't we?

If you don't wear it you wouldn't be the first person to get caught. They sometimes find it strange when you have flown several hours at altitudes where you should have been wearing your O2 mask and your O2 tank is full. Its a great thing when ATC stops you at FL340 or FL350 as a final, if you know what I mean.

Altitude Chamber
 

If you have ever been in the altitude chamber, and gone to FL350, you would demand that someone wear the mask in the airplane above 350.

When I was a 2Lt and student USAF pilot, the chamber went to 35,000 (now they only go to 25,000, I've been told). You get oxygen-stupid amazingly fast, except, in my case, I didn't even realize it--until someone put my mask back on for me.

For civilians, if you contact the FAA at Oklahoma City, they will put you in touch with the closest military chamber--and you can get a free altitude ride. VERY worth the effort. It is space-available, though.

For what it's worth: the size of the fuselage makes a difference in how long it takes to equalize the pressure if you have a catastrophic window failure. They told us in the 747 it would take about a minute at FL350 if you lost THREE cabin windows.

In the Lear 35, best estimate is 2-4 seconds.

I always wear the mask.

Many a pilot puts a clip in the side of the mask to keep it inflated and then have hanging below their chin. Most masks are NOT made for comfort- they are made to go on quickly and snugly. While this isn't all the way legal, at least it is a lot more comfortable. They do go on a lot faster than I thought they would the one time I had a door seal blow at FL400 on a 91 ferry leg.

From engine start to engine shut down right ;)

Chambers are becoming a thing of the past you'll be glad to know. the ROBD (Reduced Oxygen Breathing Device) is the up and coming training aide now. Put you in the sim or even in front of a comuter flight sim and let you fly along doing whatever your mission may be and then either sneak the hypoxia in on you or put you **immediately** to FL400+ and watch the games begin! GREAT TRAINING!

USMCFLYR