Emergency flotation system explained

Emergency Flotation Systems (EFS) are emergency systems installed on larger commercial and military helicopters in order to prevent the airframe sinking in the event of a crash landing on water. The floats may be packed within spaces inside the airframe or as externally mounted packs on the helicopter skids. The floats are inflated using gas stored in pressurised cylinders carried on board the helicopter.

History

By 1979, United States Navy and Marine Corps Boeing Vertol CH-46 Sea Knight helicopters had been involved in 64 emergency landings in water. Of the 64, 47 helicopters sunk after landing, killing 75. A study estimated 50% of those fatalities could have been prevented had the helicopters been equipped with adequate emergency flotation.^[1] Because helicopters tend to have a high center of gravity due to the high-mounted engine and transmission, even if they are naturally buoyant in the water with hatches secured, they will tend to overturn in heavy sea conditions.

Regulation

In the United States, regulations for ditching aircraft are included in Federal Aviation Regulations Parts 27 and 29, and specific guidance is provided in Advisory circulars 27-1B and 29-2C.

Design

The most rapid inflation is provided by pressurised helium although some float systems use helium blended with other gases such as nitrogen to slow down the inflation rate.

External links

• Web site: Zodiac Aero Evacuation Systems . Zodiac Aerospace . 14 April 2018 . https://web.archive.org/web/20180414234614/https://www.zodiacaerospace.com/en/zodiac-aero-evacuation-systems . 14 April 2018 . dead . Zodiac Group: AERAZUR (Cognac, France) and Air Cruisers Company (Wall Township, New Jersey, USA) are two major manufacturing sources for emergency flotation systems requirements. rde09jun09.
• Web site: Flotation . January 2017 . Dart Aerospace . 14 April 2018 . https://web.archive.org/web/20170607113200/http://www.dartaerospace.com/media/wysiwyg/Brochures_landing/DHS_6590_01_Flyers_Update_Jan2017_Flotation_VF_INTERACTIVE.pdf . 7 June 2017 . dead .
• Survey and Analysis of Rotorcraft Flotation Systems (DOT/FAA/AR-95/53) . Muller, Mark . Greenwood, Richard . Richards, Marvin . Bark, Lindley . May 1996 . U.S. Department of Transportation, Federal Aviation Administration . 14 April 2018.
• Model Testing to Establish Ditching and Flotation Stability Characteristics of Helicopters . Kidwell, John C. . Crago, William A. . June 1970 . 26th Annual National Forum . American Helicopter Society . Washington, D.C. . 14 April 2018.
• CH-53E Emergency Flotation System Design Study (NADC-79256-60) . https://web.archive.org/web/20170211101525/http://www.dtic.mil/dtic/tr/fulltext/u2/a101640.pdf . live . February 11, 2017 . Hansen, Knute C. . Lawrence, Thomas H. . July 1981 . Naval Air Development Center . 14 April 2018.
• Study on Helicopter Ditching and Crashworthiness (EASA.2007.C16) . Denante, M. . Antomarchi, P. . Couant, A. . Delorme, L. . 2007 . European Aviation Safety Agency . 14 April 2018.
• New Flotation Devices to Avoid Helicopters' Total Inversion After Capsize . Delorme, Louis . Denante, Marc . Santucci, Philippe . De Gelas, Axelle . 22–26 June 2009 . 10th International Conference on Stability of Ships and Ocean Vehicles . St. Petersburg . 77–86 . 14 April 2018.

Notes and References

1. Lightweight Emergency Flotation System for the CH-46 Helicopter (Technical Report NADC-79169-60) . Reilly, M.J. . February 1981 . Boeing Vertol Company . 14 April 2018.