Low Altitude Parachute Extraction System
Encyclopedia
Airlift (military)
An airlift is the organized delivery of supplies or personnel primarily via aircraft.Airlifting consists of two distinct types, strategic and tactical airlifting...
delivery method where a fixed wing cargo aircraft
Cargo aircraft
A cargo aircraft is a fixed-wing aircraft designed or converted for the carriage of goods, rather than passengers. They are usually devoid of passenger amenities, and generally feature one or more large doors for the loading and unloading of cargo...
can deposit supplies when landing
Landing
thumb|A [[Mute Swan]] alighting. Note the ruffled feathers on top of the wings indicate that the swan is flying at the [[Stall |stall]]ing speed...
is not an option in an area that is too small to accurately parachute
Parachute
A parachute is a device used to slow the motion of an object through an atmosphere by creating drag, or in the case of ram-air parachutes, aerodynamic lift. Parachutes are usually made out of light, strong cloth, originally silk, now most commonly nylon...
supplies from a high altitude.
This method was developed by the US Military with the assistance of the 109th Quartermaster Company (Air Drop) in 1964. In May 1965, a detachment of the 109th was formed as the 383rd Quartermaster (Aerial Supply) Detachment and sent to Vietnam. In 1966 the 109th was sent to Vietnam and took operational control of the 383rd. Both units provided Air Drop and LAPES support during the Siege of Khe Sanh in the Vietnam War
Vietnam War
The Vietnam War was a Cold War-era military conflict that occurred in Vietnam, Laos, and Cambodia from 1 November 1955 to the fall of Saigon on 30 April 1975. This war followed the First Indochina War and was fought between North Vietnam, supported by its communist allies, and the government of...
. LAPES was used to provide a method of supplying heavy loads into Khe Sanh which could not effectively be supplied by air drop. This practice was perfected at Mactan Air Base
Mactan Air Base
Mactan Air Base was a facility of the United States Air Force located on Mactan Island in Cebu, Philippines.-Location:Mactan Air Base is located on Mactan Island, off Cebu City in the province Cebu in the south central Philippines...
in Cebu
Cebu
Cebu is a province in the Philippines, consisting of Cebu Island and 167 surrounding islands. It is located to the east of Negros, to the west of Leyte and Bohol islands...
, the Philippines.
LAPES involves loading supplies on a special pallet
Pallet
A pallet , sometimes called a skid, is a flat transport structure that supports goods in a stable fashion while being lifted by a forklift, pallet jack, front loader or other jacking device. A pallet is the structural foundation of a unit load which allows handling and storage efficiencies...
on a plane. In preparation for a drop the cargo door and ramp of the aircraft is opened and a drogue parachute released. The aircraft descends to the drop altitude (typically under 2 m). Once the drop plane reaches the desired drop point, the braking parachutes for the load are released and they are extracted from the aircraft by the drogue chute and the drop load is released (retaining straps cut). The braking parachutes pull the load from the aircraft and bring it to a stop on the ground within the drop zone. The main parachutes are sized to stop the movement of the load sliding on the ground within the required space, and are not intended to control the descent of the load to the ground. Cushioning of the load is accomplished by the pallet and the material between the pallet and the load. Once the delivery is accomplished, the pilot ascends to a normal altitude and returns to base.
This method allows planes to keep in motion and present as difficult a target for enemy forces as possible while still delivering its cargo in a prompt fashion. However, the drop sequence's low altitude allows for no margin for pilot error
Pilot error
Pilot error is a term used to describe the cause of an accident involving an airworthy aircraft where the pilot is considered to be principally or partially responsible...
and a plane crash is a real danger. This method also allows planes to quickly deploy large cargo in a timely fashion instead of having to land and take off, which exposes the plane to enemy fire. This method also allows delivery of loads that are too heavy for a direct parachute descent (high altitude drop).
On July 1st 1987 during a Capabilities exercise (CAPEX) a USAF C-130E (68-10945 c/n 4325) crashed while performing a LAPES demo at the Sicily Drop Zone, on Ft. Bragg. The pilot of the C-130 had performed a LAPES drop with the same extreme rate of descent two days earlier during a practice run. The crash killed three on board, one soldier on the ground, and injured two crew.