Definition

Emergency Flotation Systems (EFS) are designed to minimise the chances that a helicopter which is involved in either a controlled ditching or a water impact sinks or capsizes as a result.

Description

The fitting of an EFS based on floats is well established, but the problem of instability on anything but a calm water surface has always been problematic. This is because of the relatively high centre of gravity of helicopters due to the location of the rotors, the transmission, and the engines.

The floats which provide EFS buoyancy are either packed within spaces inside the airframe or fitted as externally mounted packs on the lower structure. Inflation is provided by gas stored in pressurised cylinders, which are carried on board. The need for rapid inflation is met by the inclusion of helium in the gas, but it is usually blended with other gas(es)