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Testing begins for new AC unit at Charleston AFB

By Airman 1st Class Sam Hymas | 437 Airlift Wing Public Affairs | Dec. 8, 2006

CHARLESTON AIR FORCE BASE, S.C. — Since the Air Force began operations in hot climate areas, it has been in need of a more powerful air conditioning unit for heavy airlifters to keep avionics cool while they sit on blistering flightlines around the world.

They have found what they're looking for with the TMAC, or trailer mounted air conditioner, currently undergoing testing here.

FMC Technologies won the contract in January and has been engineering the new unit since. They're scheduled to deliver approximately 175 units a year and eventually supply nearly 900 of the new air conditioners to the Air Force.

"We have a lot of troops deployed in hot climates right now," said Steve Nestel, TMAC program manager for FMC Technologies. "The TMAC keeps the plane's electronics cool and allows the aircraft to sit on the ground in a hot climate without the engines running."

The TMAC, which is designed to be used with the C-17, C-5 and C-130, is one of three prototypes currently being tested. The tests at Charleston AFB, which was chosen as the lead test base, will put stress on the system to see how it performs over the long term.
"It's important to get any kinks out of the system before it goes into production," said Tech. Sgt. Jonathan Smiddy, 437th Maintenance Squadron aerospace ground equipment craftsman. "We want to catch any problems now, which will be better for the Air Force and better for (FMC Technologies)."

The testing crew arrived Nov. 27 and will be here for a total of six weeks running the machine non-stop.

"The TMAC has better capabilities for cooling avionics than the unit it replaces," said Sergeant Smiddy. "It has double the air volume; in this climate we'll have no problems keeping things cool in the aircraft. It also has simplified components making it easier to maintain."

The TMAC can pump 200 pounds of air every minute into an aircraft. The air, which is always set to a cool 50 degrees, enters the C-17's ventilation system which routes the air to first cool the avionics and then flows throughout the aircraft.

"It's been a real pleasure working with the AGE shop and Sergeant Smiddy," said Mr. Nestel. "They've been fabulous to work with and very knowledgeable about the systems.
Another prototype is scheduled to undergo high-heat testing at the Army Aberdeen Test Center in Maryland soon.