Overwing exits

Overwing exits are found on passenger aircraft to provide a means of evacuation onto the wing, where passengers either continue off the trailing edge by sliding down the extended flaps or by using an evacuation slide that deploys when the exit is opened.

Overwing exits are smaller in width and height than standard emergency exits on an aircraft, and therefore have a reduced evacuation capacity, and are typically added to aircraft where there is insufficient evacuation capacity at the main doors to obtain a 90 second evacuation, but where the addition of another set of full sized exits is not necessary to accomplish this.

Overwing exits are primarily self-help exits meaning that in an emergency evacuation the passengers seated immediately adjacent to the exit will be responsible for assessing external hazards and opening the exit.

The primary hazard involving the use of overwing exits is passengers not waiting to be given the command to evacuate, but rather initiating it themselves. While many passengers (especially frequent fliers) would believe that they are adult enough and educated enough to decide that they need to get out of an aircraft, they are not trained in the specific dangers or the sequence of events required to decide when a full-scale evacuation is needed. Also, passengers will frequently open an exit as soon as evacuation begins which may result in them evacuating into danger. This occurred in the Ryanair engine fire in Stansted Airport in 2002, where passengers evacuated themselves onto a burning wing, despite airport fire services personnel shouting at them to return inside the aircraft and evacuate via a usable exit. Typically, these problems do not occur at floor level, full sized, exit doors because these are operated by flight attendants in an emergency who have extensive emergency training.

Another hazard in the use of overwing exits is them being improperly opened (usually a result of passengers in these seats not paying attention to the verbal briefing provided pre-departure, or not observing the opening instructions on the safety card and on the exit). The majority of overwing exits involve the passenger physically removing the hatch from its frame and disposing of it outside on the wing without blocking the exit. Research conducted at the Cranfield Institute in the UK showed that many passengers are prone to leaving the exit hatch on the seat next to the exit, thereby hindering other passengers' egress through the exit.

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Wikipedia