There are two categories of exits installed on Airbus aircraft: Cabin/passenger doors and emergency exits.

Cabin doors are used in normal operations to embark and disembark passengers or perform servicing tasks. 
Cabin doors are also used as emergency exits in the case of an evacuation. 

• Emergency exits are only used in the case of an emergency evacuation. They include:
  Emergency exits that are of a similar design as cabin doors (floor level). They are available on A300, A310, A321, A330, A340, A350 and A380 aircraft.
• Overwing emergency exits that are available on A220, A320 family and A340-600 aircraft. This type of emergency exit is smaller and has a step up/step down design.

(fig.1) Examples of typical doors and exits arrangement on some Airbus aircraft

Aircraft slides are designed to be fully deployed and inflated within a maximum of ten seconds. There are three types of slide installation on Airbus aircraft.

Door-mounted slides and their inflation reservoir are installed in a container attached to the lower part of the door.

Arming a door-mounted slide attaches the girt bar of the slide to the fuselage so that when the door opens, the slide is pulled out of its container (fig.2). When the slide falls, it pulls on an inflation activation device that releases the gas contained in its inflation reservoir. 

(fig.2) Door-mounted slide of an A330 aircraft

Fuselage-mounted slides are installed in a container that is flush with the fuselage below the door frame (fig.3). The inflation reservoir is remotely installed, in the cabin, in the Overhead Stowage Compartment (OHSC) above or next to the door. 

Arming a fuselage-mounted slide moves the slide release lever of the door in contact with a slide actuation lever on the door frame. When the door opens, the slide release lever moves the slide actuation lever that releases the gas of the inflation reservoir into the slide.

Belly-fairing-mounted slides are used for overwing emergency exits. They are installed in a container that is flush with the aircraft’s belly fairing, next to the wing trailing edge (fig.4). On A321 aircraft, the inflation reservoir is remotely installed in the cargo compartment or an overhead stowage compartment. On A220 aircraft, the inflation reservoir is installed in the slide housing.

This type of slide is permanently armed in operation. It can only be disarmed and secured by maintenance personnel.

(fig.4) Principle of a belly-fairing-mounted slide of an A321XLR aircraft

Between 2021 and 2025, 155 ISDs during normal operations were reported to Airbus.

Almost 80 % of the reported ISDs occurred at the forward and aft cabin doors, which are the most frequently used doors (fig.5). ISDs at the forward cabin doors represent almost 50 % of the ISD events.

Most of the ISDs (88 %) are caused by the crew on cabin doors. However, in the last few years, we have seen an increase in ISDs caused by passengers voluntarily or involuntarily opening emergency exits and overwing emergency exits.

(fig.5) Location and responsibility of ISDs reported to Airbus between 2021 and 2025

ISDs that occur in normal flight operations are mainly caused by distraction that results in opening a door while the slide arming lever is still in the armed position.

In several reported events, the cabin crew did not follow the standard procedures and did not perform the verification and crosschecking steps.

Unusual operations like unplanned door reopening requested by ground staff shortly after the slide has been armed can cause deviation to standard procedures.

Performing an additional task, like a Passenger Address (PA) announcement during either slide disarming or a door opening procedure, has also been identified as a contributing factor.

Operational pressure, such as time pressure, or pressure from passengers to disembark, may urge the cabin crewmembers to open the door, resulting in errors.

Operator fatigue also contributed to numerous ISDs, reducing situational awareness and making them more subject to errors.

Any person that may open or close an aircraft door must be trained to do so. They must be aware of the characteristics of the doors and slides and of the threats associated with their operation.

Passengers seated near emergency exits must be fully briefed on the correct operation of the opening mechanisms to prevent accidental operation.

Strict application of the slide arming/disarming and door operation procedures can prevent ISDs.

Each airline defines their own procedures for arming/disarming and door operation in accordance with their national airworthiness authorities. The procedures need to take into account factors specific to the airline. These factors include:

• Standardization of procedures in mixed fleet operations between aircraft of different manufacturers
• The regulations of local airworthiness authorities
• Practices of ground handling companies at different airports, etc.

The procedures to disarm the slide should include three steps:

The order to disarm the slides is provided via a Passenger Address (PA) announcement.

Each cabin crewmember responsible for the door removes the safety pin from its stowage. They open the plastic cover of the slide arming lever (if installed). They fully move the lever to the Disarmed position and install the safety pin (if installed).

Each cabin crewmember responsible for the door:

• Visually checks that the lever is in the Disarmed position.
  • On A320 family aircraft, a girt bar visual indicator installed at doors 1 and 4 provides additional information to the crew about the slide’s arming condition (fig.6). When the slide is armed, the indicator aligns with an arrow on the floor.
  • On A220 aircraft, the slide status indicator at the bottom of the door turns green when the slide is disarmed.

• Crosschecks the status of the opposite door.
• Reports to the purser that both slides are disarmed.

The purser crosschecks on the Forward Attendant Panel (FAP) that all slides are disarmed.

After engine shutdown, the flight crew (PF) checks that the slides are disarmed in the DOOR SD page (DOOR synoptic page on A220), before turning off the seatbelt signs.

(fig.7) Examples of slide arming lever on Airbus aircraft

The procedure to open the door from the inside should include three steps:

The confirmation that the cabin doors can be opened is defined by each operator in accordance with their airline/airport policies.

When the confirmation that cabin doors can be opened is provided, the door operator checks:

• That the slide arming lever is in the Disarmed position
• That the safety pin is installed (if installed)
• That the cabin pressure indicator (fig.8) is not flashing red 
• The outside conditions
• The girt bar floor visual indicator (A320 family aircraft only) or slide status indicator (A220 aircraft only).

When the crosscheck is completed, the cabin crew should slowly operate the door control handle.

• If the “slide armed” indicator (if installed) comes on, the door operator must immediately set the handle back to its closed position. If the door started to move before setting the handle back to its closed position, a member of the maintenance team should be called to:
  • Check if the slide is still correctly stowed in the container before opening the door (door-mounted slide), or
  • Check that the slide inflation mechanism does not remain in a partially activated position (fuselage mounted slide).
• If the “slide armed” indicator remains off, the door operator can continue to fully move the handle to open the door.

Between 2021 and 2025, 189 ISDs during maintenance operations were reported to Airbus.

62 % of the ISDs during maintenance occurred either on an emergency exit or an overwing emergency exit. Cabin door ISDs represent 38 % of the events (fig.9).

(fig.9) Location of the ISDs reported to Airbus between 2021 and 2025

Reported ISDs that occurred during maintenance operations were either caused by:

• Opening a cabin door or emergency exit while the slide arming lever was still in the armed position, or 
• An involuntary activation of the inflation mechanism of fuselage-mounted or belly-fairing-mounted slides during maintenance.

Even if a fuselage-mounted slide is disarmed via the door arming lever, the remote inflation reservoir of the slide must be secured with a safety pin (fig.10) to prevent ISDs. Several reported ISDs occurred when the maintenance personnel forgot, or incorrectly secured the inflation reservoir of a slide, despite the fact that it was requested by the maintenance task they were performing.

(fig.10) Securing the inflation reservoir with a safety pin is often required by maintenance tasks to prevent ISDs

When performing maintenance near the activation mechanism of a fuselage- or belly-fairing-mounted slide, there is a risk of inadvertently deploying the slide. This can occur if the inflation reservoir is not securely locked with a safety pin.

Several ISDs reported on A321 aircraft during maintenance were caused by an inadvertent interaction with the slide actuation lever or slide actuation mechanism (fig.11). These incidents occurred at emergency exit doors 2 and 3 (fuselage-mounted slides), while the inflation reservoir was not secured.

(fig.11) Several ISDs reported on A321 aircraft during maintenance were caused by an inadvertent interaction with the slide actuation lever or slide actuation mechanism while the inflation reservoir was not secured

Any person that may open or close an aircraft door must be trained to do so. They must be aware of the characteristics of the doors and slides and of the threats associated with their operation. Correct application of the slide disarming and door opening procedures, described earlier in this article, is essential.

Strictly applying the maintenance procedures when performing maintenance on a door or slide is essential. These procedures provide the necessary steps to secure the slide, when necessary, to prevent ISDs.

If the maintenance personnel inadvertently interacts with the remote activation mechanism of a slide, they must report it, and set the mechanism back to its initial position to prevent ISDs.

It is important that Operators report all ISDs to Airbus. This enables Airbus to analyse their causes to identify trends and take appropriate actions to further prevent their occurrence. Reporting any slide deployment also enables checking the reliability of the slides.