The arc fault circuit breaker achieved a major milestone Friday when it made its first flight aboard a Navy C-9 (DC-9) at Naval Air Station Norfolk, Va.

Designed to protect civilian and military aircraft from wire related mishaps, the breaker is being developed jointly by the Navy, the FAA and industry.

In this six-month phase, the technology starts actual flight testing in a 727 supplied by the Federal Aviation Administration in addition to the Navy C-9 supplied by Navy Logistics Squadron 56.

“The breaker has flown (the first four days) with no problems,” said Chuck Singer of NAVAIR’s Electrical Power Systems Division and the engineer leading the development effort.

During ground testing, prototype breakers from Eaton Aerospace, one of two contractors developing AFCI technology under a joint NAVAIR, Office of Naval Research and FAA contract, were tested both at Eaton facilities and the Electrical Power Systems Lab here in four environmental tests, according to Singer.

The last battery of ground tests in the lab was done to determine the minimum safety of flight levels, Singer said, and built on previous testing done onboard a parked Navy C-9 and FAA 727 to ensure normal aircraft functions didn’t trip the breaker.
The team isn’t qualifying the breakers specifically to Navy and FAA specs, Singer explained. It, with representatives from the Air Force, FAA and industry, is working closely with the Society Of Automotive Engineering’s protection system committee to write a commercial specification for COTS equipment with room for military requirements.

“I’m very excited by the great progress of the effort and by the extraordinary level of interest from all corners of the aviation community,” said Robert Pappas, manager of the FAA’s Aging Electrical Systems Research Program.

Testing of the Eaton breaker will be followed by testing a prototype breaker being developed by the other manufacturer under contract, Hendry Telephone Co./Texas Instruments. Testing of the two prototypes is being done seperately to more efficiently use testing resources.

“The difference between the two breakers is primarily in the detection algorithms,” Singer said.

“I’m hoping to have the Hendry protoype flying by Spring (of ‘02),” he added.
Once development is completed, the new breakers can be used in both military and civilian aircraft to lessen the risk posed by aging wiring, according to Bob Ernst, head of the Navy’s Aging Aircraft Integrated Product Team. But extensive testing must be done before the new breakers go into production.

“This isn’t simple,” Ernst said. “That’s why it isn’t getting done overnight. The Navy, FAA, Air Force ALPA, NASA, SAE and industry are working together to develop a common specification. It’s better to spend a little extra time up front to make sure we get it right.”

The agencies jointly developing the specification agree that if the arc fault breaker has too many false alarms, it won’t be used.

“We know the urgency of the issue and we are all working as fast as we can, but we have to get it right,” Ernst added.

The arc fault circuit breaker is scheduled to enter production in 2002.