CRJ Door / Pressurization Question
07-05-2008 | 07:20 AM
#1
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CRJ Door / Pressurization Question
Hey guys…. So I have a question… which has somewhat been explained to me, but I’m still a little fuzzy!
I’ve been told that it’s next to impossible to open a cabin door in-flight, due to the pressure differential. Now this makes perfect sense on the over-wing exits (which are plug type); however, the MCD (and possibly the service door?) on the CRJ are not plug type – they don’t have to come back in before going out. (Or do they, and I just never noticed?)
But if they’re not plug type, and they do just open straight out… then theoretically the only thing holding them closed are the locking pins?!
So yea…. I’m probably missing something! Any of you guys that fly the CRJ want to offer an explanation?
Thanks! =)
I’ve been told that it’s next to impossible to open a cabin door in-flight, due to the pressure differential. Now this makes perfect sense on the over-wing exits (which are plug type); however, the MCD (and possibly the service door?) on the CRJ are not plug type – they don’t have to come back in before going out. (Or do they, and I just never noticed?)
But if they’re not plug type, and they do just open straight out… then theoretically the only thing holding them closed are the locking pins?!
So yea…. I’m probably missing something! Any of you guys that fly the CRJ want to offer an explanation?
Thanks! =)
07-05-2008 | 07:33 AM
#2
Prime Minister/Moderator
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From: Engines Turn or People Swim
The CRJ main cabin door is NOT a plug type door. It does NOT have to open inward first.
The only thing holding it in place is the pins and cams.
I am not aware of any pressure-based safety interlocks, so I would assume that if you pulled the handle open, the cabin door would open, and probably depart the airplane, possibly entering (and destroying) the left engine.
You would follow the cabin door into the engine in about 25 milliseconds.
The only thing holding it in place is the pins and cams.
I am not aware of any pressure-based safety interlocks, so I would assume that if you pulled the handle open, the cabin door would open, and probably depart the airplane, possibly entering (and destroying) the left engine.
You would follow the cabin door into the engine in about 25 milliseconds.
07-05-2008 | 07:58 AM
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From: Popsicle Logic
I've wondered this myself.
Wouldn't the airflow about the fuselage "hold" the door closed? I've had a Seminole door open in flight and it is impossible to close in the air due to it not being a completely airtight vessel. So, since the CRJ is pressurized there would be nothing pushing the door open aside from the person opening the door. And I doubt that person is strong enough to overcome the outside pressure holding the door closed.
Maybe?
Wouldn't the airflow about the fuselage "hold" the door closed? I've had a Seminole door open in flight and it is impossible to close in the air due to it not being a completely airtight vessel. So, since the CRJ is pressurized there would be nothing pushing the door open aside from the person opening the door. And I doubt that person is strong enough to overcome the outside pressure holding the door closed.
Maybe?
07-05-2008 | 08:03 AM
#6
Prime Minister/Moderator
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From: Engines Turn or People Swim
I've wondered this myself.
Wouldn't the airflow about the fuselage "hold" the door closed? I've had a Seminole door open in flight and it is impossible to close in the air due to it not being a completely airtight vessel. So, since the CRJ is pressurized there would be nothing pushing the door open aside from the person opening the door. And I doubt that person is strong enough to overcome the outside pressure holding the door closed.
Maybe?
Wouldn't the airflow about the fuselage "hold" the door closed? I've had a Seminole door open in flight and it is impossible to close in the air due to it not being a completely airtight vessel. So, since the CRJ is pressurized there would be nothing pushing the door open aside from the person opening the door. And I doubt that person is strong enough to overcome the outside pressure holding the door closed.
Maybe?
Maybe if the cabin was depressurized first. If the cabin is pressurized...
Lets say 8 psi...
The door is about 3ft x 6 ft (approx)...
3 x 6= 18 Square feet
Convert to inches: 18 x 144 = 2592 square inches
8 x 2592 = 20,736 pounds (over ten TONS)!
My bet is the door would pop right open...
07-05-2008 | 08:08 AM
#7
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From: FO
Maybe if the cabin was depressurized first. If the cabin is pressurized...
Lets say 8 psi...
The door is about 3ft x 6 ft (approx)...
3 x 6= 18 Square feet
Convert to inches: 18 x 144 = 2592 square inches
8 x 2592 = 20,736 pounds (over ten TONS)!
My bet is the door would pop right open...
Lets say 8 psi...
The door is about 3ft x 6 ft (approx)...
3 x 6= 18 Square feet
Convert to inches: 18 x 144 = 2592 square inches
8 x 2592 = 20,736 pounds (over ten TONS)!
My bet is the door would pop right open...
07-05-2008 | 08:15 AM
#8
Line Holder
Joined: Jan 2008
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From: CRJ
Maybe if the cabin was depressurized first. If the cabin is pressurized...
Lets say 8 psi...
The door is about 3ft x 6 ft (approx)...
3 x 6= 18 Square feet
Convert to inches: 18 x 144 = 2592 square inches
8 x 2592 = 20,736 pounds (over ten TONS)!
My bet is the door would pop right open...
Lets say 8 psi...
The door is about 3ft x 6 ft (approx)...
3 x 6= 18 Square feet
Convert to inches: 18 x 144 = 2592 square inches
8 x 2592 = 20,736 pounds (over ten TONS)!
My bet is the door would pop right open...
07-05-2008 | 08:20 AM
#9
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From: Popsicle Logic
Isn't there a story floating around of a Comair FA who accidentally tried to open the door in flight? Something about the outer handle popped out in cruise and the crew asked her to pull it back in, instead she actuated door lever thingy (technical term).
07-05-2008 | 08:23 AM
#10
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From: CRJ CA
Don't forget the MCD and the emerg. exits on the CRJ have pressure panels that open when you pull the handle. The MCD handle has two positions when you pull up. The first opens the panel and releases the pressure. The second click actually releases the door.
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