The Department of Defense (DOD) has thousands of aircraft consisting of a dozen unique aviation platforms with extremely complex electronics. Maintaining these electronics is a constant challenge. The issue of intermittent faults in electronic devices—which the DOD defines as a “momentary discontinuity, a malfunction of a device or system that occurs at regular intervals”—will always exist, and currently costs the DOD $3 billion annually.
Intermittent faults are exceptionally difficult to locate, due to the many thousands of circuit paths in modern electronics. For example, the F/A-18 aircraft contains over 27 miles of wiring and 17,000 connecting points. Traditional maintenance techniques to identify and isolate the root cause of each intermittent fault are both time- and cost-intensive because, when maintainers suspect that the interconnect wiring of a damaged system is the issue, they often check for faults, wire by wire. During this process, non-faulty components and avionic assemblies are removed, incurring preventable costs. Investigating intermittent faults used to result in a no-fault-found (NFF) outcome, due to conventional test methods’ inability to detect them.
Fortunately, a state-of-the-art technology has been developed and has been gaining prominence within the DOD to perform electrical diagnostics efficiently and effectively. Eclypse International’s Automated Wire Test Set (AWTS) enables maintenance professionals to conduct electrical and electronic system diagnostics in a fraction of the time it takes technicians to perform tests with manual equipment. Eclypse introduced the AWTS to the DOD through the Commercial Technologies for Maintenance Activities (CTMA) Program with an enhanced wiring integrity project for the Navy in November 2002. Over twenty years later, the AWTS is the longest running technology utilized in the CTMA Program, providing continually evolving solutions for wiring issues in both the DOD and the commercial sector.
“Prior to using AWTS in a preventative maintenance role, technicians performed visual inspections of aircraft wiring to check for obvious defects, but there was no electrical testing involved. With AWTS, there is both a physical inspection and an electrical test,” said David Droke, an aviation electronics engineering technician with the V-22 Fleet Support Team at the Fleet Readiness Center East’s detachment on board Marine Corps Air Station in New River, North Carolina.
The AWTS is a small, portable system that provides electrical test capability. Designed to meet requirements set by a joint DOD acquisition for deployable common test equipment for the Air Force, Navy, Army and Marine Corps, AWTS gives maintainers at home and deployed the same capability previously available only in factories and depots. Each AWTS set is designed to operate in harsh O-level environmental conditions yet is scalable to support Intermediate- and Depot-level locations. Operating software that controls the AWTS is identical across all configurations, enabling consistent training for all platforms and maintenance levels.
Because the AWTS’s capabilities can be adapted to any system that uses wires for connectivity, regardless of the system’s complexity, the AWTS can be used to test any item in the DOD inventory. Through the CTMA Program, the AWTS is primarily being used on aircraft platforms such as the F/A-18, V-22, H-6, H-47, H-60, C-130, C-5, and F-16. The technology is also being used as a quality control check for newly manufactured rotary wing aircraft before delivery to the DOD, further reducing costs to both the OEM and DOD. Additionally, it is being used to test ships and ground vehicles.
“As soon as AWTS was delivered in 2010 we immediately began using it for I-level testing on the V-22 platform to help the technicians with a faster test,” said Droke. “We’ve used AWTS in a limited capacity at an I-level for about ten years, and for a scheduled maintenance requirement at the O-level for two years. The main benefit from a preventative maintenance perspective is the electrical wire inspection. AWTS enables maintainers to target problematic areas during scheduled maintenance to prevent them from developing into a system or wiring failure between scheduled maintenance intervals.”
AWTS is capable of testing multiple circuits at a time, with the least amount of weapon system disassembly, significantly reducing maintenance times. By lowering the number of disconnection points for checkout and troubleshooting, AWTS reduces risk of damage to onboard computers and avionics. A key benefit includes reductions in the amount of support equipment needed, and the overall time and cost of maintenance. AWTS provides rapid identification and condition of a fault intuitively to maintainers.
“Broken wires are easy to find. Technicians can easily find them with a multimeter,” said Droke. “However, other issues defined as degraded wires are harder to find. These include chafed wire insulation, broken wire strands, and contacts that are contaminated, corroded, or under-crimped. AWTS helps identify those issues.”
Within the DOD, the AWTS has been quickly finding electrical problems, reducing no-fault-found (NFF) rates and test times, resulting in efficient and thorough diagnosis of electrical problems. Serving as an integral part of the condition-based maintenance plus (CBM+) environment, the AWTS can also predict when wiring may need to be changed to prevent potential failures and unscheduled maintenance activities.
In short, the AWTS has been helping to shift the DOD maintenance paradigm from reactive to proactive. Aircraft scheduled for deployment are now prepared by inspecting systems prior to departure. This has resulted in more reliable mission-ready aircraft with less unscheduled maintenance in the field.
Droke highlighted one added benefit of AWTS. “In order to run the system, the aircraft connectors have to be clean, with no oil, dirt, water, or grease, before they can test it,” he said. “Needing to clean the connectors is driving maintainers to do something that is preventative in nature because cleanliness is key for rotorcraft that operate in harsh environments. Because maintainers perform inspections and thorough cleanings, the wiring system is in better condition, which helps to prevent failures.”
The AWTS technology has also moved into the commercial sector, supporting fleets of aircraft from passenger planes to shipping industries. Its applications will likely continue to expand.
“The result of using AWTS on aircraft is a healthier wiring system and a reduction in NFF,” said Droke.