Desert heat overwhelms flight-line AC units

Flight-line air conditioning units at U.S. bases in the Middle East are conking out because of the extreme heat, jeopardizing missions in the war zones.

The more than 100 faulty units are being modified by Air Force engineers for now and will be replaced in 2012 or 2013, when new ones are ready for delivery. The air conditioners date back to the 1990s and are in five countries — Iraq, Afghanistan, Qatar, the United Arab Emirates and Kuwait.

Engineers have already developed a misting system for one model and are revamping two others. The Air Force didn’t put a price tag on either the modifications or the new units.

The problem lies with avionics systems in aircraft, which can’t be switched on until sufficiently cooled. If the avionics system is too hot, the aircraft must fly for an hour or more, until its internal cooling system can bring down the temperature of the avionics system.

“It is preventing maintenance, causing the rescheduling of maintenance, and potentially rescheduling flights,” said Harry Smith, an engineer with the 642nd Combat Sustainment Group at Robins Air Force Base, Ga. “It is a serious … concern.”

The units die when the temperature hits 120 or 125 degrees, depending on the model, Smith said.

In Qatar and the UAE, where most of the units are, the mercury routinely hits 140 on the flight line.

“What we’re encountering there is the worst possible environment for an air conditioner,” said Smith, who deployed to Qatar and Kuwait a year ago to inspect failing air conditioners at the request of Air Combat Command. “The problems are widespread in the [area].”

When Smith and the rest of his team returned home, they retooled the ACE-802 model with the misting system, which allows the unit to operate at temperatures 20 degrees higher than before.

Now, the Air Force is working on other modifications for the 42 ACE-802s, used to service the EC-130H, Joint Stars and Airborne Warning and Control System aircraft, as well as changes to 75 MA-3D units that cool C-130s and fighter jets and five DAC-110s, which are used on B-1s and other aircraft, he said.

The companies that make the service’s two primary air conditioning systems visited Robins in June and came up with systems modifications that are now being tested, according to Paula Fleming, chief of the Aerospace Ground Equipment Flight in the 578th Combat Sustainment Squadron at Robins.

http://www.airforcetimes.com/news/2009/12/airforce_air_conditioners_121109/