Overwing Exits - Hazards

Hazards

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 their 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.

Additionally, during aircraft evacuations, it has been found that the majority of overwing window exit designs of Boeing 737 (NG) Next Generation Line along with the Airbus A320, hamper evacuation in comparison with traditional floor level exits due to the inherent "step up and through motion" required of passengers as they exit the aircraft, unlike the designs of older generation wide body aircraft such as the McDonnell Douglas DC-10 and Lockheed L1011 which are all floor level.