Emergency Flotation Systems (EFS) are emergency systems installed on larger commercial and military

helicopter A helicopter is a type of rotorcraft in which lift and thrust are supplied by horizontally spinning rotors. This allows the helicopter to take off and land vertically, to hover, and to fly forward, backward and laterally. These attributes ...

s in order to prevent the

airframe The mechanical structure of an aircraft is known as the airframe. This structure is typically considered to include the fuselage, undercarriage, empennage and wings, and excludes the propulsion system. Airframe design is a field of aerospa ...

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 The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage ...

and

Marine Corps Marines, or naval infantry, are typically a military force trained to operate in littoral zones in support of naval operations. Historically, tasks undertaken by marines have included helping maintain discipline and order aboard the ship (refle ...

Boeing Vertol CH-46 Sea Knight The Boeing Vertol CH-46 Sea Knight is a medium-lift tandem-rotor transport helicopter powered by twin turboshaft engines. It was designed by Vertol and manufactured by Boeing Vertol following Vertol's acquisition by Boeing. Development of th ...

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. 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 The Federal Aviation Regulations (FARs) are rules prescribed by the Federal Aviation Administration (FAA) governing all aviation activities in the United States. The FARs comprise Title 14 of the Code of Federal Regulations (CFR). A wide variety o ...

Parts 27 () and 29 (), and specific guidance is provided in

Advisory circular __NOTOC__ Advisory circular (AC) refers to a type of publication offered by the Federal Aviation Administration (FAA) to provide guidance for compliance with airworthiness regulations, pilot certification, operational standards, training standards, ...

s 27-1B and 29-2C.

Design

The most rapid inflation is provided by pressurised

helium Helium (from el, ἥλιος, helios, lit=sun) is a chemical element with the symbol He and atomic number 2. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas and the first in the noble gas group in the periodic table. ...

although some float systems use helium blended with other gases such as

nitrogen Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at se ...

to slow down the inflation rate.

References

External links

* 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. * * * * * * {{cite conference , url=http://www.shipstab.org/files/Proceedings/STAB/STAB2009/STAB_2009_s01-p3.pdf , title=New Flotation Devices to Avoid Helicopters' Total Inversion After Capsize , author1=Delorme, Louis , author2=Denante, Marc , author3=Santucci, Philippe , author4=De Gelas, Axelle , date=22–26 June 2009 , conference=10th International Conference on Stability of Ships and Ocean Vehicles , location=St. Petersburg , pages=77–86 , accessdate=14 April 2018 Helicopter components