MAPS, PREL achieve 100% availability of work cages

MALMSTROM AIR FORCE BASE, Mont. — All 17 of the 341st Missile Wing’s guided missile maintenance platforms became available for field use Jan. 14, according to Lt. Col. John Briner, the 341st Missile Operations Squadron commander. This feat is unprecedented in recent memory.

Commonly known as a “work cage,” the GMMP achieved 100 percent availability, marking a significant achievement that capstones efforts by Air Force Global Strike Command and the depot at Hill Air Force Base. Addressing the sustainment issues with this essential piece of equipment, the GMMP repair was one of 32 actionable items identified for missiles through AFGSC’s Force Improvement Program last year.

It also highlights the continued dedication of the 341st MOS’s mechanical and pneudraulics section (MAPS), the unit responsible for inspecting, certifying and repairing the mechanical components on the work cages. The squadron’s power, refrigeration and electrical laboratory (PREL) made the repairs to the GMMP’s electrical components. The two sections work closely to keep the work cages serviceable.

“We’re really proud of what we’ve accomplished as a team,” said Master Sgt. Michael Braun, the MAPS NCO in charge.

Work cages are required for almost every maintenance task in a Minuteman III launch facility’s underground launch tube, from replacing components to repairing sump pumps at the base of the tube. The GMMP is an Air Force-specific platform that is purpose-built at Hill AFB from sourced parts. At the launch facility, the GMMP’s motor is locked into a rail around the top of the tube, while a two-person basket is suspended from the motor by cables. The GMMP allows technicians to traverse the narrow space around the missile as high as 70 feet from the bottom of the tube.

“It is a piece of life-support equipment, so inspections are a lot more detailed than for most equipment,” Braun said. “It has to be impeccable because someone’s life is hanging from this basket.”

The wing typically needs up to 12 operable GMMP units to fulfill daily maintenance and training requirements, Braun said. Two GMMPs are taken to every maintenance task requiring a work cage, in case one unit fails and a rescue operation becomes necessary. Additionally, training requires two GMMPs. The wing operates 150 launch facilities, and with multiple maintenance jobs each day throughout the complex, the work cages are in high demand. 

A dwindling supply of replacement parts made it increasingly difficult for MAPS and PREL to keep the minimum number of work cages ready. The problem was compounded when stress fractures from years of use were found last year in many of the cast aluminum frames that support GMMP motors.

“At that point, it becomes condemnable,” Braun said. “The supply system had run out, so there was no support for that said piece of equipment. We had to make more equipment unserviceable and we were down to maybe three or four work cages going through the spring.”

By summer, the lack of serviceable GMMPs had caused a backlog of maintenance tasks throughout the wing. Maintenance jobs had to be prioritized based on work cage availability.

“It pushes everything,” said Tech. Sgt. Robert Richards, a MAPS team chief and trainer. “Mission-wise, it pushes the requirements you have of swapping out components or fixing a sump pump or whatever they have you doing out there. You just keep bumping it further down the road. Then those begin to (pile) on one another to the point where, for the other shops, they’re swamped trying to play catchup.”

Staff Sgt. Nathan David, a MAPS team chief, said he and other team members were often called back to work in the evening to repair faulty GMMPs.

Some repairs can only be performed by other agencies. For example, because the GMMP is a life-support system, only certified welders can fix damage to metal parts. The 341st Civil Engineer Squadron repairs the baskets and electrical boxes, and the Montana Air National Guard repairs the cast frames.

“We only have those two options,” David said. “It’s not something we’re allowed to do in our shop.”

There were occasions when a MAPS technician would be sent to the guard base with a damaged cast frame. The technician had instructions not to come back until the frame was fixed because the need for it was so critical, Braun said.

Inspections by MAPS often revealed discrepancies with the GMMP electrical boxes. PREL would then tackle that problem, a labor-intensive procedure if the electrical boxes needed to be taken apart.

“It takes about six hours to disassemble the electrical box and another six hours to put it back together,” said Staff Sgt. Joseph Lyons, a PREL team chief and trainer. “It’s very time-consuming and hard on the hands. It’s all cramped, tight work.”

Last year, the wing’s inventory of GMMPs was scaled down from 26 to 17. This gave the Hill AFB depot parts for engineering analysis and allowed them to find, buy or manufacture replacements, including the problematic cast frame. As new parts arrived at the base in the fall, MAPS and PREL made repairing work cages a top priority.

The FIP initiative that created a separate survivable systems team to perform launch control center maintenance in the field — tasks formerly assigned to MAPS — has also helped MAPS focus on GMMP repair, Braun said.

He added that the benefits are already quantifiable. First, there isn’t as much wear or tear on serviceable units, because the inventory can be rotated instead of used daily. Secondly, there is no longer a same-day rush to repair and certify GMMPs back into the field, which means they are inspected more thoroughly. As a result, this increases users’ confidence in MAPS and PREL.

Because MAPS is so far ahead now with GMMP repair — which accounts for fewer than a dozen of the 225 tasks the section performs – Braun’s shop can now focus on tasks that were falling to the wayside. 

“Over the last year, our overdue and broken equipment just kept piling up because we had to spend all of our time keeping this one type of equipment working,” he said.