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==