By Jim Jenkins
Aging Aircraft Public Affairs

NAVAIR PATUXENT RIVER, Md -- Picture yourself as 19-year old avionics technician on your first cruise. The Navy has trained you meticulously and given you the best possible tools to perform your job. You’re assigned to a strike fighter squadron, performing a routine scheduled maintenance inspection on an aircraft set to go on the next launch. Looking over the log book, you notice a nagging up-gripe but cannot duplicate the error. The tools supplied to you, are the best the Navy can buy. You perform the inspection and give the go ahead that the plane is ready for tasking.

The aircraft takes off as planned with a mission to perform air strikes on a high profile target. But before the pilot reaches the target a fire breaks out in one of the electrical compartments. The pilot is forced to abort the mission and return to the ship.

Further investigation reveals the fire started in the very compartment you inspected and said was OK. You asked yourself, “How could this have been avoided?”

Wiring troubles are a rapidly growing problem on Naval aircraft today.

Today’s jet aircraft rely more and more on sophisticated electrical and computer systems, placing a premium on the reliability of wiring, power feeder cables, connectors and circuit protection devices. It’s time to stop treating wire as a “fit and forget” item and begin treating it as a system, said Jerome Collins, Branch Manager for the Wiring Systems Branch at the Naval Air Systems Command (NAVAIR).

Having Automated Wiring Analysis (AWA) tool sets will go a long way to begin treating aircraft wiring as a system and will prove critical to the safety and readiness of fleet aircraft. With these diagnostic tool sets Sailors and Marine maintainers will be able to work proactively to stop the plague of wiring failures.

The AWA advanced off-board diagnostics capability enables a modular approach to automated wiring systems evaluation from single wiring harnesses to complete aircraft. The electronic analyzer system detects faults and the single wave reflectometry handheld device allows for fault location and waveform analysis.

NAVAIR’s Wiring Systems Branch and Aging Aircraft Integrated Product Team (AAIPT) have been involved in the development of the AWA Program as a research and development project for the last five years, taking it from its early design phase to operational evaluation with fleet squadrons.

The end product the Wiring Systems Branch and the AAIPT are looking for in fielding these diagnostic tool sets is a specification. Chad Madden, AAIPT Wiring Team Lead, said the team hopes to create specifications for advanced diagnostic systems by analyzing trend data gathered from the AWA tool sets they are now fielding.

The trend data collected, by AAIPT Wiring Team member Tim Faux, is essential in determining the AWA Program’s return on investment and its value to fleet maintenance activities. Baseline maintenance data will be collected prior to the deployment of the AWA program to maintenance activities. This is historical data for the specific system under test in which the AWA test program set (TPS) is designed for. The AWA TPS includes both the testing software for the AWA equipment and the interconnecting cables for each system. The baseline maintenance data will be used as a basis for comparison once the AWA program has been deployed.

Baseline test data will be collected at set intervals after the AWA program has been deployed. Data collected from the Eclypse RTS-501 Analyzer will be compared directly to current data input in Naval Aviation Logistics Command Management Information System (NALCOMIS). The test data will be collected on the specific system the TPS was designed for both proactive and reactive testing. The proactive data collection will help to identify trends in wiring systems and repair anomalies during scheduled maintenance before they cause a non-mission capable problem.

“What we would like to move towards is the proactive approach of doing scheduled maintenance on equipment and be able to locate underlying problems that haven’t surfaced yet,” Collins said, “and to fix those before they become unscheduled maintenance events.”

Unscheduled maintenance results in an average of 1 million man-hours spent each year on wiring related problems. The AWA diagnostics tool set was designed and implemented to tackle unscheduled maintenance events.

The long term goals of the AWA Program are to reduce wiring related maintenance efforts, reduce wiring related mission aborts, reduce false equipment removals, and to establish a proactive maintenance capability.

“The way we’re looking at the proactive maintenance capability is evaluating the data we’re pulling off of these test sets against reliability centered maintenance criteria,” Madden said. “Basically rating failures and time logged to identify hot spots for cyclic maintenance as opposed to waiting until something breaks, or conversely inspecting too frequently.”

Current metrics show that some wiring related failures are attributed to maintenance itself. Damage sometimes occurs when personnel use wire bundles as ladder rungs, step on wire hidden under insulation blankets, improperly use clamps, and improper installation which all can lead to wire chafing which has the potential to cause dangerous arcing events. The idea is to find an acceptable amount of scheduled maintenance that can provide a proactive look yet not be a major readiness degrader, and find these potential problems before they manifest into greater catastrophes, Madden said.

“When I was in the Navy, I would have killed to have something like the [AWA tool set],” said Madden, a former Aviation Electronics Technician. “It would have been most beneficial for use on four main systems -- the navigation, communication, radar, and weapons systems where the sheer amount of wiring connections is daunting to the maintainer who has to go in there and find the problem. The AWA diagnostics tool set gives maintainers the advantage and enables him to find and fix faults faster than ever before.”

The diagnostics tools offer a quick automated evaluation of the important characteristics of wiring continuity, isolation, inductance and capacitance, Madden said. It will basically ensure that power and signals inserted into the electrical systems reach their intended destination.

The RTS-501 provides accurate test results on all wiring circuits, from simple cables and harnesses to complex printed circuit boards, relay panels and circuit breaker panels. The 501 can also be stacked in a daisy chain to allow up to 128,000 points of switching, and can handle 3,500 continuity tests per minute.

The ESP+ works in conjunction with the 501 by performing distance to fault diagnostics. If a fault is detected with the RTS-501, the ESP+ can provide a very accurate distance to fault (an open or short) using standing wave reflectometry, and provides steady state measurements as opposed to pulse based measurements. The ESP+ can determine the presence of an open or short in an electrical cable and measure that distance so a maintainer doesn’t have to trace an entire wire run to locate the problem area. It can detect faults in a variety of cable types including coaxial, single shielded, pairs in shielded, one of pair to shielded, twisted pair unshielded, adjacent wires unshielded, wires in the same bundle and wire to structure.

Use of the RTS-501 analyzer together with the ESP+ handheld meter will also help alleviate issues with wiring material properties, proper installation of wiring, wiring fault detection, poor maintenance tracking, and training. Having these diagnostic tools will also help to eliminate potential problems like the one in the fictional scenario at the beginning of this article.

The AAIPT Wiring Team conducted field evaluations of the tool set involving the S-3, E-6, EA-6B, C-2, H-46, H-60, F-15 and H-53 aircraft. Upon roll-out and system shake-down, the Eclypse tool set earned its money right away in each of the aircraft platform evaluations. In on instance, the analyzer found a miss-wire in the auto-pilot system and a burn-through of a wire in the flight control system that the aircraft’s maintenance team did not know about beforehand.

“No one would have ever known there was a problem until the aircraft was in trouble,” Madden said. “When the auto-pilot was supposed to turn on to level the plane out of a steep dive, it wouldn’t have.”

In a demonstration of its capabilities at Pax River’s AIMD Work Center 690, the 501 was used to test the left and right wiring harnesses of a P-3 T-56 engine on the harness build-up board. Eclypse technical director, Kevin Steidel, working with AAIPT Wiring Team member, David Dudziec, attached the wiring harness to the 501, which was plugged in to a ruggedized laptop computer running Microsoft Windows and Eclypse’s ELITE operating system. With a click of the mouse the 501 performed three tests in the blink of an eye. The 501 tested for isolation, integrity and continuity faster than the currently deployed equipment used at most ‘I’ level shops in the Navy.

Work Center 690 Sailors were wowed at the speed with which the RTS-501 accurately and descriptively provided the results of the tests.

One Sailor asked, “How soon can we get one here?”

Use of these diagnostic tools in the fleet will greatly reduce the number of mishaps and aircraft down-gripes. Real Sailors and Marines now have the ability to find potential problems before they manifest into mission degraders like the one the fictional Sailor experienced.