physics

Low-altitude parachute-extraction system

Low-altitude parachute-extraction system is a physics topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Low-altitude parachute-extraction system rather than just read about it. In short: The low-altitude parachute-extraction system (LAPES) / Low-level parachute extraction resupply system (LOLEX) is a tactical military airlift delivery method where a fixed-wing cargo aircraft can deposit supplies in situations in which landing is not an option or in an area that is too small to accurately parachute supplies from a high altitude. This practice is no longer used in the USAF.

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Reference excerpt

The low-altitude parachute-extraction system (LAPES) / Low-level parachute extraction resupply system (LOLEX) is a tactical military airlift delivery method where a fixed-wing cargo aircraft can deposit supplies in situations in which landing is not an option or in an area that is too small to accurately parachute supplies from a high altitude. This practice is no longer used in the USAF.

Development 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 Battle of Khe Sanh in the Vietnam War. 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 in Cebu, Philippines.

Operation Preparation for a LAPES delivery includes loading cargo on a pallet rigged with two types of parachutes (chutes). The drogue chute is used to pull a cluster of larger extraction chutes out. The deployed extraction chutes will then pull the load out of the plane. Floor locks hold the pallet in place until extraction time. The LAPES delivery procedure begins by slowing to approach speed, lowering the ramp, and opening the cargo door. To preclude damage to the aircraft from an inadvertent contact with the ground, the landing gear is lowered. The aircraft approaches the extraction zone in a manner similar to landing. On command of the pilot, the drogue chute is released and allowed to trail behind the aircraft on a tether. As the pilot flares and achieves a wheel height of 1-2 meters above ground, the drogue chute is allowed to pull the extraction chutes out into the airstream. The force of these chutes overcomes the floor locks, pulling the pallet across the ramp, out of the aircraft, and onto the extraction zone. The pilot adjusts the flight controls to remain level during the extreme change in the aircraft center of gravity caused by the pallet movement. While the pallet slides to a stop using the extraction chutes as a brake, the pilot climbs away from the extraction zone and raises the landing gear. On climb out, the rear cargo door is closed and the ramp is raised, completing the sequence. LAPES enables 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. The technique also allows delivery of loads that are too heavy for a direct parachute descent (high altitude drop). However, the drop sequence's low altitude allows for no margin of pilot error and the risk of plane crash is heightened.

Crashes On November 16, 1982, CC-130H 130329 of the Canadian Forces crashed during a LAPES operation at Namao when the load failed to clear the aircraft causing it to crash. On July 1, 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 Fort 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 and one soldier on the ground, and injured two crew.

References

Illustrations

Worked examples

Example 1 — a first encounter with Low-altitude parachute-extraction system

Start with the simplest possible case. Write down what Low-altitude parachute-extraction system claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In physics, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Low-altitude parachute-extraction system before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Low-altitude parachute-extraction system ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Low-altitude parachute-extraction system

In research: Low-altitude parachute-extraction system appears in physics research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Low-altitude parachute-extraction system in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Low-altitude parachute-extraction system is common in secondary-school and first-year university syllabi. It links to neighbouring topics Low flying, Military logistics, Parachuting, so understanding it makes those chapters shorter.
In everyday life: Look for Low-altitude parachute-extraction system outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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Frequently asked questions

What is Low-altitude parachute-extraction system in simple terms?

Why does Low-altitude parachute-extraction system matter?

Because it connects several physics ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Low-altitude parachute-extraction system?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Low-altitude parachute-extraction system.