Colorado Helicopters, Inc. holds the FAA STC and PMA for a very unique side hook. It is certified on Hughes 500D and McDonnell Douglas 500E, F, FF, 520N (Notar), and MD 600 helicopters.
The Purpose of the side hook bracket is to allow the pilot to quickly rig a Hughes or McDonnell Douglas 500, 520, or 600 Series helicopter for pulling sockline on powerline construction projects. The system is certified for a maximum side pull load of 1,900 lbs.see the photograph of the components of the system. The 12" ruler in the photograph is simply to give you an idea of the size of the device. It is very small compared to most side hook setups.
The bracket (in the center of the photograph) is inserted into the rear step hole on the left side of the helicopter. The bracket is pinned in place with the same quick release pin that just held the left rear step in place. The quick release pin holding the step in place has a shear strength of about 8,000 lbs. The helicopter cargo hook is then removed from the belly of the aircraft and is pinned in place on the bracket for side pull operations.
Once the initial installation is completed, it takes the pilot less than one minute to move the original cargo hook from the belly to the side mount position or from the side mount position back to the belly. In both positions the same electrical and manual releases work as always.
For the initial installation the cargo hook manual release cable must be replaced permanently with a longer one (like the one in the photograph). It is seven inches longer than the normal manual release cable. The normal cable proved to cause some unnecessary premature releases. CHI holds the STC and PMA for these longer cables.
The placard (in the photograph) is mounted on the side of the aircraft near the side hook installation (very close to the left rear step hole). It is required by the FAA in the USA. It may not be required in other countries. The quick release pin in the photograph permanently replaces the bolt that now holds the cargo hook on the belly.
The old bolt is not used again to mount the hook. The same quick release pin (the one in the photograph) is also used
to mount the cargo hook on the side mount bracket.
The small aluminum devices in the photograph are "fuse links," designed to break at a predetermined overload. We put one between the cargo hook, mounted on the side of the helicopter, and the sockline to insure that the airframe of the aircraft is not overloaded due to a snag in the sockline while the pilot is pulling rapidly. Side pulling speeds can be reached in excess of 35 miles per hour with this device.
We also have certified break-a-way swivels that function as both fuse link and swivel. The swivel comes apart but is held together with a calibrated breaking strength pin. If the airframe is about to be overloaded the pin will break and allow the cable being pulled to fall away from the aircraft. You only need to replace the small calibrated pin with a new one and resume pulling operations once the problem is corrected.
We also provide an FAA approved "Flight Manual Supplement" for the Hughes or McDonnell Douglas Flight Manual.
Sockline Pilots love this device. It is quick to change from carrying passengers to pulling sockline and back again to hauling passengers (one minute). When pulling hard, the cyclic stick is centered with full cyclic authority. If the break-a-way device breaks, no unusual attitudes result. The pilot easily comes immediately to a normal hover. There is little possibility of damage to the airframe.
Currently I am selling the device for U.S. $5,000.00. The breakaway swivels sell for an additional $300 apiece plus $10.00 each for the breakaway pins that go inside the swivels. We usually use 5 to 8 of the swivels per job to avoid having to carry them back to the start of the pull each time. If you prefer the aluminum break-a-way links, they sell for U.S. $50.00 each.