Helicopter Aircrew Breathing Device

The Helicopter Aircrew Breathing Device or HABD (also known as a HEED or SEA ) is a piece of military survival gear which was adopted in order to increase the chances of survival for embarked troops and aircrew trapped in an aircraft which has ditched (crashed into a body of water.) Similar in function to SCUBA gear, it consists of a small cylinder pressurized with atmospheric air and first stage regulator worn in a pouch on the user's life vest; a pressure gauge; an air hose and a special second-stage regulator (the part that delivers air via the user's mouth). The regulator is on-demand (it only delivers air when the user breathes in) and is designed to be highly rugged in order to survive impacts associated with emergency ditchings.

History and Design

Since a full-size SCUBA cylinder would be prohibitively bulky, especially for troops already laden with full combat gear, the HABD must be small and thus limited in capacity. It provides roughly two minutes of air at the surface. This decreases rapidly with depth and with the heightened breathing rate that accompanies stress. Despite this limited capacity, the amount of air they provide has aided in survival.

Helicopter ditchings usually come with little warning, often while the pilot is attempting a ship landing or other low-altitude maneuver. Because they are top-heavy, ditched helicopters invariably flip upside-down upon hitting the water. The crew and embarked troops will be bombarded with violent jerking motions and several tons of incoming water, which causes unsecured gear to fly uncontrolled throughout the cabin and can knock troops unconscious. Jet fuel and hydraulic fluid often seep into the cabin and can cause blindness to open eyes and lung damage if inhaled. Troops unfortunate enough to find themselves in a ditched helicopter will be upside-down, disoriented, often in the dark and in a rapidly sinking helicopter. Immersion in cold water evokes a "gasp" response in humans, which limits their breath-holding ability to as little as 15 seconds. The HABD, properly used, provides troops with an invaluable tool to help ward off panic and buys them precious extra time to escape.

The HEED device was developed by Larry Williamson, a diver, in the late 1970's. Soon after the success in the dive market other industries began to call and ask if they could use Spare Air in their situations as well. It was modified and sold to the military in 1984 under the name Helicopter Emergency Egress Device (HEED) to help helicopter personnel from almost certain death in the event of an water crash. It is now used by most military and government organizations here in the US and in most developed countries around the world. The best part is that several dozen lives have been saved and many more people have reduced injuries due to the use of this product. The Navy has also adopted the product to protect workers from smoke inhalation in the case of an engine room fire. In the event of ditching, the HEED would provide additional time to escape from a submerged helicopter.

Technical Specifications

Cylinder volume1.5cf/42.5 liters
MaterialAluminum
Cylinder length10.5"/26.67 cm
Rated pressure3,000 psi/206 BAR
Weight3 lbs/1.36 kg
Duration of air supplyApproximately 12-15 breaths at 33 ft/10m assuming 1.5 litre breath volume.

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References

  1. "Helicopter Aircrew Breathing Device User's Manual" (PDF). aqualung.com. Retrieved 15 September 2019.
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