|Quoting Revelation (Reply 210):|
Quoting Mortyman (Reply 194):
A lever in the cockpit gives the crew in cockpit opportunity to shut the door completely during emergencies. If the door is locked in this way inside the cockpit, it is not possible to open the door from outside , even if a pilot or flightattendant on the other side knows the code.
Yes, that is correct. Here is another link: http://www.efbdesktop.com/airplane-general/sys-1.3.1.html
For mode LOCK: Momentarily placing the cockpit door switch to LOCK illuminates the red cockpit access panel light, rejects keypad entry request, inhibits aural alerts, and prevents further access code entry for 20 minutes. The cockpit door switch returns to NORM when released, but remains in locked mode for 20 minutes or until UNLOCK is selected.
This is different for mode NORM: When NORM is selected, it allows the door to be locked when closed. It also allows the door to be opened after an emergency access code entry and 30 second delay in case of pilot incapacitation.
So we see once the switch is moved to LOCK the door will NOT open for 20 minutes unless the switch is put into NORM or UNLOCK.
I see some continuing confusion here about the locking procedure for the cockpit door. I'm not a pilot, but I have carefully watched the Airbus youtube video. The link quoted by Revelation above to a screenshot helps clarify the Airbus youtube video posted upthread. I urge everyone who has questions about the locking procedure to view the link above, and also the entirety of the Airbus youtube video, found here, because it takes a bit of thinking to understand the various modes:
Let me try to encapsulate the procedure as I understand it from the links:
In the YouTube video - First at the 2:40 mark, it shows the procedure for the pilots locking and unlocking the door, after they have locked it due to a perceived threat (in the video, it's a flight attendant forgetting the proper procedure). It clearly shows the captain reacting to a possible threat, toggling the switch to "LOCK" (it springs back to the "NORM" position, but now the "LOCK" mode has been triggered). The "LOCK" mode can only be overridden by the pilot's lifting up the switch and moving it to the "UNLOCK" position. The video says that the entry keypad is disabled for 5 minutes after the "LOCK" mode is toggled.
Then, at 3:55, the video proceeds to the emergency-entry override scenario, in which the pilots are unconscious and the attendant has to enter a code, wait 30 seconds, and then, if no action is taken by the pilots, has 5 seconds to get in the door. But what the video doesn't directly say, which has confused me until repeated viewings of the video, is that this emergency-entry method in the video was run from the "NORM" mode - it only works if the system has not already been set to "LOCK." It works only if the system was in "NORM" mode before the pilots became unconscious.
One discrepancy: the "efbdesktop.com" link at the top confuses things a bit when it states that if the switch is toggled to "LOCK," the external emergency override is disabled for 20 minutes, not the 5 minutes stated in the video. So I don't know whether the co-pilot could have locked the other pilot out for 20 minutes or for 5 minutes. But it backs up the video when It says that only in the "NORM" mode (which is different from the "NORM" POSITION - because even in "LOCK" mode the toggle springs back to the "NORM" position) can the external emergency override trigger the 30-second warning before the door opens.
From what I can tell, the video and the link are saying that if the "LOCK" mode is selected from inside the cockpit, the emergency override code cannot even be entered, until either 5 minutes or 20 minutes expire, whichever would be correct for a Germanwings A320. It would seem that the only communication then would be to use the interphone to request entry.
Could some more knowledgeable Airbus pilots please confirm that I have it correct? I'd like to try to consolidate the understanding of the door lock system.