The effect of overwing hatch placement on evacuation from smaller transport aircraft.

Overwing exits are installed on a number of smaller transport aircraft. With a traditional overwing exit, once released, the hatch is not attached to the fuselage and will fall into the cabin. To operate, the hatch has to be brought inwards, manoeuvred and placed in a location where it does not obstruct egress. Accidents and experimental studies have shown that the hatch is not always disposed of into an appropriate location. Evacuation trials from a smaller transport aircraft cabin were conducted. The placement of the exit hatch was manipulated. The results indicated that hatch placement had a significant effect on passenger evacuation rates from a smaller transport aircraft, with the internal placement tested resulting in slower evacuation rates. The study has highlighted the importance of operators disposing of the hatch into a location whereby it does not impede egress. One way to ensure this would be the installation of an automatically disposed hatch. Statement of Relevance: It is important that all occupants can evacuate an aircraft rapidly if required. The influence of overwing hatch placement on evacuation from smaller transport aircraft was addressed Evacuation trials concluded that an inappropriately placed hatch can negatively influence evacuation rates. Improvements to exit design and passenger education were suggested.