For pilots, they tell us these are not plug type doors, thus the flight lock mechanism for the handle. Maybe for you mechanic types, they are really semi-plug type doors, but they don't tell us that.

Normally, the Blue Door Ground Mode light is illuminated on the ground when the pin locking mechanism for the handle is unlocked. In the air, the Blue Ground Mode light extinguishes, with the door handle locking automatically. If the light stays illuminated in the air, an EICAS message for the Upper Door appeared and we had to position a Flight Attendant at the door with less than 3 psi to prevent the door from possibly being opened inflight, because it is not a plug type door, and would open up and out, presumably being ripped off the fuselage. Above 3 psi, it was not necessary to position the FA at the door because there was no threat of anyone being physically able to open the door at higher psi's.

 

5 hours ago, Captain_Al said:

For pilots, they tell us these are not plug type doors, thus the flight lock mechanism for the handle. Maybe for you mechanic types, they are really semi-plug type doors, but they don't tell us that.

It just seems strange that the doors have to go upwards (and inwards at the top).

Shouldn't higher psi's assist the opening of a non-plug type?

(EDIT) Just found a section in the maintenance manual which says it is a plug type.Reference AMM 52-23-00 page 1.

Cheers

JHW

P.S. I remember checking the Upper Deck Door inflight locking actuators on the ground by putting a spanner over the air/ground sensors on the nose. With hydraulics off, it is possible to force some systems into air mode by just fooling the nose gear sensors. I seem to recall it also affected electrical system loadshedding, which caused various side effects in the cabin.

 

All I know is there is a procedure for the upper deck door for low PSI situations with the door handle unlocked inflight. For higher PSI's, there is no threat, thus no FA by the door, with the upper deck door handle unlocked.

We must not be thinking of this right, because I am thinking the same way you are that higher PSI's would actually assist in opening a non-plug door. We were told at the higher PSI, you will not be able to move the handle, not that I would want to try, if the handle is unlocked inflight.

7 hours ago, Captain_Al said:

All I know is there is a procedure for the upper deck door for low PSI situations with the door handle unlocked inflight. For higher PSI's, there is no threat, thus no FA by the door, with the upper deck door handle unlocked.

Yes, I've applied this MEL a few times. It may be because:

the plug is not as good as the main deck doors (It appears to be only on the top and bottom, not the sides)

the geometry of the door mechanism allows greater force to be applied to the door

the door is smaller (?), so less force is required to open it

Cheers

JHW

 

Sounds reasonable to me, I did not realize it had plug characteristics on the top and bottom, probably not designed to hold it if it opened inflight. But, it qualifies for a semi-plug type door.

Just to clarify, my options were more speculation than known facts, Captain Al ;) The opening sequence seemed to suggest that the top and bottom were part of the plug. There may be something in the mechanism I've overlooked.