airdrop

A humanitarian aid supply drop.

An airdrop is a type of airlift, developed during World War II to resupply otherwise inaccessible troops, who themselves may have been airborne forces. In some cases, it is used to refer to the airborne assault itself. Early airdrops were conducted by pushing small crates with parachutes out of the aircraft's side cargo doors. Later cargo aircraft were designed with rear access ramps, lowerable in flight, that allowed large platforms to be rolled out the back.

As aircraft grew larger, the U.S. Air Force and Army developed low-level extraction — allowing tanks and other large supplies to be delivered, such as the M551 Sheridan or M2 Bradley. Propaganda leaflets are also a common item to airdrop.

In peacekeeping operations or humanitarian aid situations, food and medical supplies are often airdropped from United Nations and other aircraft.

Types of airdrop

Freedrop packs being dropped out of an RAF C-130 Hercules

The Type of airdrop refers to the method that the airdrop load descends to the ground. There are three main types of airdrop, and each type may be performed via several methods.

• Low-Velocity Airdrop is the delivery of a load involving parachutes that are designed to slow down the load as much as possible to ensure it impacts the ground with minimal force. This type of airdrop is used for delicate equipment and larger items such as vehicles.
• High-Velocity Airdrop is the delivery of a load involving a parachute meant to stabilize its fall. The parachute will slow the load to some degree but not to the extent of a Low-Velocity airdrop as High-Velocity airdrops are used for durable items like MREs. LAPES (Low altitude parachute ejection system) is a variation of an HV drop where the aircraft almost completes a touch-and-go type pattern (without actually touching the ground) and the load is ejected at an extremely low altitude. This is shown in the photo of the C-130 airdropping a tank.
• Free Fall Airdrop is an airdrop with no parachute at all. Common uses of this type of airdrop include the delivery of humanitarian aid supplies and leaflets used in Psychological warfare.

Methods of airdrop

The method of airdrop refers to the way the load leaves the aircraft. There are three main methods of airdrop currently used in military operations.

• Extraction airdrops use an extraction parachute to pull the load out of the aft end of the airplane. In this method, an extraction parachute is deployed behind the aircraft which pulls the load out and cargo parachutes are deployed to slow the load. Extraction drops are invariably Low-Velocity airdrops.
• Gravity airdrops use gravity in the sense that the attitude of the aircraft at the time of the drop causes the load to roll out of the plane like a sled down a hill. The most common use of a gravity airdrop is for the Container Delivery System (CDS) bundle.
• Door Bundle drops are the simplest of airdrop methods. In a door bundle airdrop, the Loadmaster simply pushes out the load at the appropriate time.

Historically, bomber aircraft were sometimes used to drop supplies, using special supply canisters that were compatible with the aircraft's bomb attachment system. During World War 2, the British and Americans used bombers to drop weapons to the Polish Home Army during the Warsaw Uprising.

Gravity airdrop of CDS bundles from a C-17.

Extraction airdropping a light tank.

Food supply crate mounted under a German He 111 bomber, (1944)

References

Technical Order (TO)13C7-1-11 Airdrop of Supplies and Equipment: Rigging Containers. Department Of The Air Force. September 2005. 

Technical Order (TO)13C7-1-5 Airdrop of Supplies and Equipment: Rigging Airdrop Platforms. Department Of The Air Force. August 2001. 

See also

• Loadmaster
• Winged tank
• Operation Manna
• 395 Air Despatch Troop

External links

• 47 Air Despatch Sqn RLC The British Army's only remaining unit specialising in airdrop.

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