Teal’s qualification reflects the DTIC’s conclusion that, although “an effective tool for determining the distance to a known short circuit or an open circuit,” the Eclypse ESP is not perfect. “The accuracy of the result depends on using a relative velocity setting which is appropriate for the cable under test,” Quinn writes. “Some impedance settings can produce erroneous results when testing cables with a short circuit. Intervening connectors or terminal post connections may bias the results for a particular electrical cable run.” Still, when compared to the time, effort, and potential damage caused by exposing open wiring first and then trying to find the fault, the ESP is an excellent place to start.”
The Eclypse ESP can operate on wires up to 1,000 feet long in temperatures ranging from -20 C to +60 C, and can store 99 different preset parameters for testing different kinds of wire. It weighs 1 pound, 3 ounces, and is about the size and shape of a scientific calculator.
The ESP in action
Not surprisingly, the Eclypse ESP has found its way into the Department of Defense (DoD), with thousands of the units already being deployed by the Army, Air Force, and Navy. In particular, ESPs are being used in battlefield locations in Afghanistan and Iraq, where the need for fast problem diagnosis in rough conditions makes it an ideal frontline tool. Besides in-theater usage, Eclypse ESPs are being included in DoD’s Battlefield Damage Assessment & Repair (BDAR) Kits. These are small, portable kits included on military aircraft such as the UH-60 Blackhawk helicopter, to allow fast repairs during unexpected AOG incidents.
“In Afghanistan and Iraq, many of the aircraft take constant fire from AK-47s and RPGs on the ground,” says Teal. “The pilot and crew are only protected by a floor plate of steel, and the rest of an aircraft is vulnerable to small arms fire. It damages the wiring bundles inside, causing shorts and critical system failures. In these cases where an aircraft is downed away from its base, the BDAR can be used to assess whether the ship can be brought back into action quickly, or whether it should be destroyed to keep it out of enemy hands. A technician equipped with an ESP can often troubleshoot an electrical failure and get the ship patched together fast, so that it and the crew can return to fight another day.”
Given its NASA heritage and the DoD’s embrace of the Eclypse ESP, one would expect the FAA to follow suit. After all, SWR technology was developed to prevent another TWA 800 in-flight fuel tank explosion, in which “the most likely [cause] was a short circuit outside of the CWT that allowed excessive voltage to enter it through electrical wiring associated with the fuel quantity indication system,” says the NTSB report on the accident.
Yet despite this fact, the FAA has not recommended use of tools like the Eclypse ESP for commercial and civil MRO use. According to Teal, the FAA has publically stated that nondestructive testing tools “are not ready for prime time use.” Airlines have taken this message to mean that the ESP is not up to the job, he adds.
So what does the FAA have to say? According to FAA spokesperson Les Dorr, “The FAA does not ‘approve’ test equipment. A manufacturer or repair station may develop production or maintenance procedures and identify the appropriate test equipment, when necessary. As far as we know, no civil aircraft manufacturers or repair stations have instituted procedures that call for the use of the Eclypse ESP.”
Meanwhile, a January 2007 report jointly issued by the FAA and the U.S. Department of Transportation titled, “Commercial Off-the-Shelf Wiring System Diagnostics Evaluations “ (available online at www.tc.faa.gov/its/worldpac/techrpt/ar0661.pdf) had this to say about the FAA’s testing of the device: “The ESP proved to be a very useful tool for open and short defect detection. However, the location detection capability was somewhat limited, and it is not clear that the limitations were entirely due to VOP [velocity of propagation] issues.”
“We’re somewhat frustrated with the FAA not validating or stating acceptance use of the ESP for commercial/civil use, when NASA and DoD clearly have so much proven faith in it,” says Christopher Teal. “Granted, it is not a perfect device, and we have never said that it was; no test equipment is. But as a low-cost fault location tool, the ESP is a profoundly useful device, and one that could make a real difference on the MRO shop floors of America.”
The bottom line: For MROs, the Eclypse ESP could be a highly valuable fault location tool, with or without the FCC’s recommendation. Certainly NASA and DoD have faith in this technology.
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