erasmus
Posts: 256
Joined: Thu Jun 07, 2007 11:46 pm

Opening Overwing Exit In Flight.

Fri Apr 12, 2002 5:41 am

I was reading this thread in the civil aviation forum:
http://www.airliners.net/discussions/general_aviation/read.main/791879/

Of course I know that an overwing can't be opened when there is a big differential pressure.

But what if the aircraft is at very low altitude and at very low differential pressure?

How much differential pressure should there be, to prevent an adult from opening a typical overwing exit?
 
jsuen
Posts: 204
Joined: Tue Aug 14, 2001 2:36 pm

RE: Opening Overwing Exit In Flight.

Fri Apr 12, 2002 5:58 am

The smallest exit allowed by the FAA is 19 inches by 26 inches, or 494 square inches. If an adult can exert 250 pounds, about 0.5 psi. That's around 1,000 feet.
 
delta-flyer
Posts: 2631
Joined: Mon Jul 30, 2001 9:47 am

RE: Opening Overwing Exit In Flight.

Fri Apr 12, 2002 11:47 am

But doesn't the cabin pressurize while still on the ground, so there is always a differential pressure? How much differential pressure are fuselages designed for, anyway?

Pete
"In God we trust, everyone else bring data"
 
air2gxs
Posts: 1443
Joined: Mon Jun 18, 2001 1:29 pm

RE: Opening Overwing Exit In Flight.

Fri Apr 12, 2002 1:08 pm

Most aircraft types are rated for 8.5 to 9.5 psid. It just depends on the aircraft type. Also some aircraft beginning pressurization on the ground but it isn't really that much, probably arourd .25 psid as the aircraft screams down to the runway. Any more than that on the ground and the pax start feeling it.
 
delta-flyer
Posts: 2631
Joined: Mon Jul 30, 2001 9:47 am

RE: Opening Overwing Exit In Flight.

Sat Apr 13, 2002 11:48 am

Thanks air2gxs

Pete  Smile
"In God we trust, everyone else bring data"
 
dc10hound
Posts: 460
Joined: Fri Dec 15, 2000 4:18 pm

RE: Opening Overwing Exit In Flight.

Sun Apr 14, 2002 3:56 am

>>Also some aircraft beginning pressurization on the ground but it isn't really that much, probably arourd .25 psid as the aircraft screams down to the runway. Any more than that on the ground and the pax start feeling it<<

It's called "Pre-Pressurization". When the throttles are advanced, the Cabin Outflow Valve(s) modulate towards the closed position. Sometimes you can feel it.
"Eagles soar. But weasels never get sucked into jet intakes.."
 
Contact_tower
Posts: 534
Joined: Mon Sep 17, 2001 4:05 am

RE: Opening Overwing Exit In Flight.

Sun Apr 14, 2002 5:09 am

The airliners with outwards opening exits (like the B737) has bolt locks that activate when the engines are running or something like that.

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