ROBINS AIR FORCE BASE, Ga. -- A small group of people in a building near the flightline at Robins perform a task that saves a lot of lives and a lot of expensive aircraft.

The Hydrostat Shop performs a variety of tasks, but its primary duty is maintenance of fire extinguishers placed in the engine area of aircraft. If an engine catches fire, pilots activate the units.

The significance of their job is not lost on the 20 people who work in the shop.

"The job here is very important," said Frank Jackson, a pneudraulics systems mechanic, as he tested a unit. "When the pilot hits that button, our bottles better work."

Called fire bottles, the units come in varying sizes, but most are round and about the size of a bowling ball or basketball. The units must be serviced every five years, said Steve Rozier, also a pneudraulics systems mechanic. The shops works on fire bottles from every aircraft in the Air Force inventory except F-22s.

Servicing the bottles involves draining the fire suppressant, which is halon, then filling it with water and subjecting it to two or three times the pressure that it would be expected to have when in service. The pressure is so great that it causes the unit to expand. If there are any leaks, the unit is scrapped.

It used to be that when they drained the halon out, it would be sent to Richmond, Va., for reprocessing, then shipped back to Robins to be put back into refurbished units. But about four years ago the decision was made that it would be more efficient to do the reprocessing at Robins, so now the Hydrostat Shop has a climate-controlled building next door where it keeps about 150,000 pounds of halon on hand in half ton tanks. Very little halon is lost in the process, so the shop's supply comes almost entirely through recycling.

Another change that has taken place in the shop is the way it paints the bottles. About four years ago the shop became one of the first at Robins to paint using a powder process. The powder is sprayed onto the bottles, then the bottles are put into an oven and baked. The baking turns the powder into a glossy finish.

The primary benefit of the process is that it is more environmentally friendly, Mr. Rozier said, because it avoids the chemicals and fumes that come with standard painting. It also makes for a sturdy finish that is tough to scratch. It works so well, he said, that BMW and Harley Davidson are using the same process. Other units on base are beginning to use it too and have visited the shop to see how it works.

But it's not just aircraft fire extinguishers that are maintained in the shop. Standard hand-held fire extinguishers - about 6,000 in buildings across Robins - also come through the shop once per year for recharging.

The shop also does other work, mostly related to hydraulics and anything that might be in a pressurized bottle. Those include oxygen bottles in planes and nitrogen bottles. It also refurbishes the bottles that fire ejection seats in fighter jets.

Another project the shop will soon undertake is servicing the hydraulic unit that operates the nose landing gear of the B-2 bomber.

Some of the work in the shop doesn't even directly involve hydraulics or fire bottles. As Mr. Rozier gave a tour of the shop Tuesday, Rosa Jackson worked on the mechanism that activates the cargo door of a C-130 and Mark Windham worked on a similar part for an F-15. 

"We are definitely multi-skilled," Mr. Rozier said.