Monday, April 11, 2005

N911JA or why RVSM is a good thing

I don’t have the whole story yet but from what I’ve been told a friend’s life was saved by RVSM (Reduced Vertical Separation Minimums). Starting in January of this year unless your airplane has been approved for flight in RVSM airspace you are limited to FL 280 or below. He was flying N911JA in the high 20’s when a 18” hole blew out the bottom of the pressure vessel. Odds are, if not for RVSM he would have been in the low 40’s when the explosive decompression happened.

We practice emergency descents every time we go to Flight Safety and the drill is always the same…the instructor yells “boom you just lost the cabin”. We reach behind and don our oxygen masks and in one motion kick off the autopilot, retard the thrust levers, deploy the spoilers, and drop the landing gear, pointing the nose down to keep the airspeed on the barber pole. We hold that speed until we are at a safe altitude and the exercise is complete. BTW we also know it is coming because it is the only time we have the Sim at FL410 all week .

In the Sim it works every time. In real life I have strong doubts anyone would survive no matter how good the training. In the low 40’s the best conditioned pilot has less than 20 seconds to get on oxygen. While I’ve timed myself putting on my mask and I can do in a little less than 10 seconds that is in a normal environment, not the world of a decompressed cabin at FL430.

The first problem is you would not be able to breath, in fact all the air has been sucked out of your lungs and you would be in intense pain from the expansion of any trapped air. You would not be able to see, the cabin would be full of condensation, and the noise would be deafening. The cold alone would be defeating. You would be fighting panic: yours, your co-pilot’s and any passenger’s that could reach the cockpit. It is a world that is hard to imagine and impossible to simulate.

That’s the bad news, not much chance you will make it out alive. The good news is it doesn’t happen often and if you are so unlucky that it happens to you it will be over with quickly.

BTW I flew N911JA for almost a year back in 2001.

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