What does "arming a door" mean? Is the orange tape that's applied over a window related, perhaps as an indicator to people outside that the door is armed?

enter image description here

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    $\begingroup$ Ever since 911 they want to make sure doors can defend themselves. The bottom line here is: don't mess with an aircraft door, because they know how to handle themselves. $\endgroup$ Feb 27, 2015 at 17:19
  • $\begingroup$ @Tyler Your username is really appropriate for that comment. $\endgroup$ Feb 27, 2015 at 19:23
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    $\begingroup$ @SteveJessop: Nobody trusts the windows anyway after _NSAKEY was found. $\endgroup$
    – dotancohen
    Mar 1, 2015 at 18:09
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    $\begingroup$ @Honza - I appreciate the edit suggestion, but do you have the source/credit for the picture? $\endgroup$ Jun 13, 2018 at 15:21
  • $\begingroup$ @JamesThorpe Sorry for the late answer - I took the picture myself with my phone. $\endgroup$ Apr 30, 2020 at 9:11

3 Answers 3


If a door is put into armed mode, it will trigger the evacuation slide when the door is opened.

Prior to departure (usually before engine startup), all the aircraft doors are placed into the armed (or automatic) mode by the cabin crew. Methods of arming vary from aircraft to aircraft, but ultimately the girt bar (a metal bar attached to the door end of the slide) is physically attached to brackets either in or adjacent to the door sill.

[...]If a rapid evacuation is required and the doors are opened while "armed", the opening of the door pulls the slide pack out of the bustle (because the girt bar is physically attached to the aircraft floor)

This is also the reason for the famous All doors in flight announcement:

DOORS TO ARRIVAL AND CROSSCHECK “Flight attendants, doors to arrival and crosscheck.”

Meaning: Occasionally heard as “disarm your doors and crosscheck,” and announced by the lead flight attendant or purser as a plane approaches the gate. The intent is to verify disarming of the emergency escape slides attached to the doors. When armed, a slide will automatically deploy the instant its door is opened. Disarmed, it needs to be deployed manually. On departure the slides are armed to facilitate an emergency evacuation. (You might hear this as “doors to automatic.”) Upon docking, they’re disarmed to keep them from billowing into the boarding tunnel or onto the apron during servicing.

The orange or yellow tape is a visual indicator for ground workers or ramp agents that the doors are armed or not armed. The visual indicator can vary, it can also be built into the door lock mechanism, triggering a visual indicator externally if the door is locked and armed. In the following picture, the orange tape is not strapped over the window, which should indicate an unarmed door. In the video that this image is taken from, the flight attendant has just locked and possibly armed the door, the other flight attendant would place the orange tape over the door window during "cross-check".

enter image description here
(Image Source: YouTube "B757-200 Door Closing" - Author: Exupery747)

  • $\begingroup$ Well out of what I really know about — but from memory, around Europe, it's always one of the pilots who announces changes to the door's armedness. $\endgroup$
    – gsnedders
    Feb 27, 2015 at 23:43
  • $\begingroup$ Airline Ops dependant, can be flight deck or purser. $\endgroup$ Feb 28, 2015 at 13:17

When the door is armed, the slide will deploy when the door is opened.

The tape is indeed an indicator to people outside that the door is armed.

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    $\begingroup$ Can somebody from the 'outside' open an armed door? $\endgroup$
    – Firee
    Mar 2, 2015 at 10:22
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    $\begingroup$ @Firee Sounds like that should be a new question, with the potential for some "amusing" videos... $\endgroup$ Mar 2, 2015 at 20:43
  • $\begingroup$ @Firee For example in this A321 video (from 2:40) it shows that opening from outside automatically disarms the door. youtu.be/Vbm8MpC0e1o $\endgroup$ Apr 7, 2019 at 16:50

Yes. Someone can (and unfortunately has) opened an aircraft door while still armed. Some aircraft have an indicator that is visible from the outside indicating the door is still armed. Other aircraft require indincation from flight attendants (such as a thumbs up) indicating the door is disarmed. Older single isle aircraft (727 DC-9) the slides would fall out of slide pack but not inflate. Flight attendants would have to pull an inflation handle at the part of the slide attached to the floor of the aircraft after opening the aircraft door. This was an economic feaure for airlines as slide deployment are expensive. If the slide deploys but not inflated they were just rolled back into the protective covering. However these were dangerous in actual emergencies as flight attendants would have to reach down and inflate slides and could be pushed out. The ones that automatically inflate are dangerous if opened accidentally if they are deployed into a jetwat or catering vehicle

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    $\begingroup$ IIRC the Airbus training video shows that opening the door from outside disarms them as part of the process. I would expect the newer Boeing types to work the same. $\endgroup$
    – Jan Hudec
    Apr 4, 2016 at 5:01

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