The remote hook/electric long line system, shown on the left, is used to transport external loads under a helicopter.  It features a cargo hook at the bottom of the long line that can be opened by operating a control switch up in the helicopter.  This permits the helicopter to transport a load to a remote location, place it on the ground, disconnect the load from the long line, and return to the base--all without having to land the helicopter and without the necessity of ground personnel at the remote site.

The system consists of the remote hook, the electric swivel, the electric long line, and the hand-grip control switch.  (Click on a link in the image to the left to go to the webpage describing the component.) The long line is available in lengths from 30 ft. to 200 ft.

SAFETY CONSIDERATIONS:  Delivering loads by helicopter to unprepared sites can be hazardous!  Rotor downwash can "kick up the dust" to produce a condition of near-zero visibility, known as "brownout."  Snow particles, blown and suspended by downwash, can cause a "whiteout."  The ability to deliver loads without the helicopter having to land (using the remote hook/electric longline system), even when no ground crew is present, eliminates hazards from dirt, snow, and other airborne foreign objects.

When a helicopter is used to transport goods to a distant location and time is critical, it is not uncommon for the helicopter to land, leave the motor running and the rotor moving while the freight is unloaded by the ground crew, and then to quickly take off.  Many accidents have occurred as a result of people near or under a moving rotor.  When the remote hook/electric longline system is used, the ground crew, if present, works at a safe distance from the helicopter above.  Hooking and unhooking operations are easier and safer.  Communication between ground personnel is easier. The crew member in the helicopter operating the handgrip control switch has both the vantage point and the responsibility to see that the external load has landed and the ground crew are in safe positions before he opens the remote hook.  However, the remote hook can also be opened manually by the ground crew.

STATIC ELECTRICITY:  Helicopters coming in to land or landing an external load usually have static electricity at different potentials than the earth below.  Fortunately, the discharge current, when contact is made, is typically so small that it does not cause problems. However, during very dry weather the static charge can be very high, resulting in electric shocks to the ground crew, ignition of flammables and/or damage to electronics and other equipment.

Charged particles are generated by the engine exhaust.  Rotor downwash moves charged particles to an external load suspended below the helicopter in a manner similar to a Van de Graaff generator. When the electric long line is used, the ground wire connects the remote hook and the external load to the chassis of the helicopter, thus, preventing build-up of a large charge between the helicopter and the external load below.

Static wicks, such as the two mounted on the trailing edge of the stabilator of a Pave Hawk helicopter, shown on the right, bleed off static charges as they build up during flight.

CERTIFIED AIRWORTHY:  Extensive testing of the remote hook-electric long line system was performed by the Redstone Arsenal of the U.S. Army. The Airworthiness Certification was issued for this system.