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-   -   Plug doors (https://www.pprune.org/tech-log/403244-plug-doors.html)

Beeline 29th January 2010 16:13

Can't believe somebody has uploaded the training videos on youtube, takes me years back hearing the narration.

When watching the video, the door mechanisim is best seen when the attendent is closing the door. The little tabs at the edges of the door are the structural pressure bearing stops. The door swings in but when the handle is drawn down, the door with its stops move down vertically, aligning with the stops on the airframe aperture. This takes the pressure loads from the door into the structure. The opposite happens when opening.

Hence this is a plug type door.

HAWK21M 29th January 2010 18:06

Any door when in closed position is larger than its cutout is a Plug type door.
The Entry/Gall/Bulk cargo doors on the B737 are examples.
The end gates above & below the cabin doors move to enable the door to move inside the cutout before closing.

atkin8 7th March 2011 08:17

Door unlocked
 
Hi,
Thanks for your input on the passenger doors
I am still in the dark as when the doors can open.
The landing altitude is set in the cockpit and the local QNH ,is this related to the doors.

Any reply appreciated.
Atkin

aviatorhi 7th March 2011 09:43


You will not open Boeing or Airbus doors in flight!! No matter how strong you are.
While I agree based on the math of a pressurized airplane I'll throw in a technicality... what if you depressurize first and then open it in flight? :}

On a more serious note I remembered the DB Cooper incident when I was reading through the replies, while the door in the aft bulkhead on a 727 is a plug type door it opens inward only. From my point of view (I go in and out of it often enough) and from a purely functional stanpoint it's near identical to the L-1 door (well duh, it's a door), but I'm wondering how much pressure, if any, DB Cooper was dealing with when he went to do that. I doubt it was 8.6 DPSI, but I bet someone knows the exact figure.

Swedish Steve 7th March 2011 10:38

A little story for those that are worried about doors opening in flight.

A320 nightstop. Aircraft is left on the ground service bus, all the doors are closed and a ground air heater is plugged in.
The temp is around M15, and the arriving crew have read their FCOM and without asking the engineer have pushed the ditching switch.
In the morning the new crew come down the jetty. The door is closed, and the cabin pressure warning light in the door is flashing. The dispatcher, who usually opens the door, says that he can't open it. The Captain says that the flashing light MUST be a false warning and heaves up the lever to open the door. The FO catches him as he is propelled across the jetty by the door opening explosively.
He should have heard the hissing noise as the air escapes past the door seals, obeyed the warning light, and asked the ground crew to turn off the heater.

The little ground heater can pressurise the aircraft enough to nearly seal the door closed.

Old Fella 7th March 2011 10:47

Opening doors in flight
 
It has been a while, however my recollection is that on the B747 the cabin smoke evacuation procedure called for both No1 and No 5 (L or R) to be cracked open to provide air flow through the cabin. Of course the procedure also called for flight below FL140 (to preclude the rubber jungle) and depressurisation of the aircraft. Never had to do it in operations, but the procedure was there.

captjns 7th March 2011 12:06

aviatorhi states...


On a more serious note I remembered the DB Cooper incident when I was reading through the replies, while the door in the aft bulkhead on a 727 is a plug type door it opens inward only. From my point of view (I go in and out of it often enough) and from a purely functional stanpoint it's near identical to the L-1 door (well duh, it's a door)
aviatorhi asks


but I'm wondering how much pressure, if any, DB Cooper was dealing with when he went to do that. I doubt it was 8.6 DPSI, but I bet someone knows the exact figure.
The answer aviatorhi's question is 0 PSI Diff. as the aircraft was depressurized. The DB Cooper switch was installed in 1972 after a few incidents to prevent the ventral stairs from being lowered in flight. The DB Cooper Switch is a spring loaded vane that rotates 90 degrees.


http://upload.wikimedia.org/wikipedi...ooper_Vane.JPG

On the ground the plate which is attached to the vane is out of the way of the ventral stairs for normal operation. A preflight item is to ensure that the spring in the vane operates as it should. As airflow hits the vane, it rotates about 90 degrees so that a plate will cover the ventral stairs to prevent operation during flight.

All doors, including cargo doors on the 727 are plug type doors.

aviatorhi 7th March 2011 12:32


All doors, including cargo doors on the 727 are plug type doors.
Thanks for the info on the DPSI when that occured, but that statement there is incorrect, the right side cargo (pit) doors are hinge type doors which open outward (except on certain 727-200s which had 3 cargo doors in which the aft one is a plug door). The cargo converted 727s I fly all have hinge type main cargo doors which lock into place with 6 big locks on the bottom and (I believe) 5 camlocks along each side.

captjns 7th March 2011 16:05

On the727, starting with the cargo door closed, when you actuate the cargo door handle the door moves up a bit above it's lip before the door actually opens, thus technically the cargo doors are plug type.

mono 7th March 2011 18:03

Ampclamp - If you can find any "dirty great C latches" on a 'bus door you get a prize. There ain't any. The door is a plug because when it's shut the door drops, and door and frame stops line up, thus holding it against a/c pressure.

itsresidualmate 7th March 2011 18:30

A ground heater will also pressurise a 146/RJ. The area of the pax door means it's virtually impossible to raise off it's stops. I can just manage to force the avionics hatch open with my shoulder when it happens.

aviatorhi 7th March 2011 21:36


On the 727, starting with the cargo door closed, when you actuate the cargo door handle the door moves up a bit above it's lip before the door actually opens, thus technically the cargo doors are plug type.
Myself and the Aircraft Manual respectfully disagree. The upward motion is only necessary for the locks to clear above the locking components on the side of the door.


2 . Passenger/Crew Doors
A. Forward Entry Door
(1) The forward entry door is on the left side of the airplane. It is
an inward-outward opening plug type of door which can be operated
from inside or outside the airplane.


4 . Cargo Doors
A. ALL EXCEPT 727-200;
There are two cargo compartment doors on the lower right side of the
fuselage, one serving each cargo compartment. Both doors are hinged at
their upper edges and open inward. Access panels are provided in the
external skins of the cargo doors, to enable manual release of the cargo
door latches if the operating mechanisms fail. Except for slight
differences of shape, both doors are identical in design and operation.
Access to the aft cargo door is covered by the trailing edge of the wing
to body fairing. The rear end of this fairing is a separate section
mounted on rails so that it can slide aft to allow access to the cargo
door.
B. 727-200;
There are three cargo compartment doors on the lower right side of the
fuselage. The No. 1 and 2 cargo doors are hinged at their upper edges
and open outward. The No. 3 cargo door is a plug-type, inward opening
door. All three cargo doors have a balance mechanism which
counterbalance the door weight. A portion of the trailing edge of the
wing to body fairing is attached to the No. 2 cargo door. When the door
is locked, the outboard handle is flush with the exterior of the fairing.
The outboard handle is connected to the door latching mechanism by a
control rod.

I'm unsure as to the exact nature of the doors in Paragrah A, however Boeing does not describe them as plug doors, as I've never flown a 100, Paragraph B applies to me, but is not true of all 200s just some have the 3 door option, all the ones I've flown only have 2.


captjns 8th March 2011 01:31

I've got lots of hours on the old -100... no greater bird in the sky.

Anyway I don't have the Boeing 727 Mx Ref. Man. on this computer to send you a graphic. But the the initial actuation of the cargo door on the -200 lifts the door out of it's sill about an inch before opening outward. True on the surface the door does not appear to be a plug type door, but per Boeing's descriptin it is.

Next time you fly the jet check it out.


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