When the Air Force needs a lift: the 1107th Aviation Classification and Repair Activity Depot had a problem: how to load AOAP lab vans with low ground clearance onto Air Force transports. The solution was to change the angle of the loading ramp.
The Missouri Army National Guard's 1107th Aviation Classification and Repair Activity Depot (AVCRAD), while attached to the Army Materiel Command Logistics Support Element-Southwest Asia in Kuwait, was tasked with coordinating the lab's move. Weighing the load, calculating its center of balance, assigning transportation control numbers, completing hazardous goods declarations, and conducting pre-move processing and inspections were completed without incident. Precise load planning was critical because the 141-inch-high AOAP lab van was only 1 inch lower than the vertical limit of the C-17 Globemaster that was to transport it. However, the 52,000-pound van's low ground clearance and the angle of the aircraft's loading ramp presented even greater challenges for loading the lab's van and tractor.
The AOAP lab van has built-in, underside compartments and landing legs with ground clearances between 14 and 19 inches. These 14-foot long compartments are situated midway between the front and rear axles of the tractor-van wheelbase. (See drawing above.) The standard C-17 ramp consists of a 20-foot-long main ramp with a ground support pedestal and an 8-foot "toe" approach ramp that rests on the ground. The main and approach ramps have angles of 9 and 12 degrees from horizontal, respectively, assuming a loading floor height of 68 inches. The C-17 ramp cannot be adjusted to lessen these angles.
If the AOAP van were to back up this standard ramp configuration, the van's low midsection would "bottom out," or strike, at the apex of the ramp and the C-17 floor because the ramp angles and the van's 24-foot wheel base would not allow enough bottom clearance for the van. It was apparent that a pre-engineered load-and-unload solution would be needed at both departure and arrival airports to overcome this obstacle.
So that the AOAP van would not bottom out during loading, the ramp angles had to be decreased. This required constructing portable supplemental ramps to use with the existing C-17 ramp system. The supplemental ramps could travel with the AOAP lab van and be available for loading and off-loading at any location. The AVCRAD contacted the Air Force Air Transportability Test Loading Agency at Wright-Patterson Air Force Base, Ohio, for assistance in determining the ramp angle needed to load the AOAP lab van.
Design calculations indicated that a change of one degree in the C-17 ramp angles would allow a 1 1/2-inch clearance by the AOAP van. This prediction was based on a distance of 68 inches from the C-17 floor to the ground. Two devices were needed: a ramp pedestal to raise the main C-17 ramp support pedestal and a pair of toe ramp extensions to raise and extend the approach ramp.
The supplemental devices were built by AVCRAD personnel using 3/4-inch plywood lumber, cut into appropriate forms and glued and screwed together. The ramp pedestal was made of five stacked sheets of 18-inch by 30-inch plywood. Each approach ramp extension was built using 10 plywood forms with 3/4-inch spacers on each side and an internal "I-beam" construction to ensure support of the van and tractor weight. (See drawing above.)
The proof of a plan is apparent in its execution. The AOAP van equipment and supplemental ramp system deployed to the departure airfield, and the supplemental ramps were installed. When the AOAP van was slowly backed up the ramp onto the C-17, the ramps provided ample support and the AOAP van cleared the ramp apex by about 8 inches. Following the successful load, the ramps were removed and loaded on the aircraft. On arrival at their destination, the ramps were used again to offload the tractor and AOAP van.
CHIEF WARRANT OFFICER (W-4) ROBERT M. LANNING, MISSOURI ARMY NATIONAL GUARD, IS A UH-60 BLACK HAWK HELICOPTER MAINTENANCE OFFICER WITH THE MISSOURI ARMY NATIONAL GUARD'S 1107TH AVIATION CLASSIFICATION AND REPAIR ACTIVITY DEPOT IN SPRINGFIELD, MISSOURI. HE RECENTLY COMPLETED A YEARLONG ACTIVE-DUTY DEPLOYMENT WITH HIS UNIT TO KUWAIT, IRAQ, AND AFGHANISTAN, WHERE HE SERVED AS THE SOUTHWEST ASIA THEATER ARMY OIL ANALYSIS PROGRAM COORDINATOR. HE HAS B.S. AND M.S. DEGREES IN GEOLOGY FROM PENNSYLVANIA STATE UNIVERSITY.
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|Author:||Lanning, Robert M.|
|Date:||Jul 1, 2005|
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