A new look at wiring problems

Mech, Fall, 2004 by Ed Taylor

The Naval Air Systems Command has Ken a direct path to identify and fix wiring problems: They are sending out teams around the fleet to do material-condition assessments and inspection-techniques training.

These assessment teams are made up of representatives from NAVAIR, the TYCOM, or AIMD, and squadron. Their work is twofold: Inspect aircraft for wiring problems, and give three segments of training. The material condition part looks at wiring, connectors, clamps, and grounding, team takes photos of all problem areas to aid a command debrief and to provide tools for the training segments. An example of a recent assessment was a West Coast, Marine H-53 squadron. The team spent one week looking at wire-and-cable integrity, connectors and structural-support devices, equipment installations, maintenance issues and repairs, and safety-of-flight issues.

That assessment revealed wiring on the aircraft inspected was in good condition, with a few exceptions. The team found many in-line splice--most were old window type, and some were corroded. They also found the wrong size and type of splices (one connecting two different gauges of wiring). The wrong wire was found, as were supply issues for ordering replacement roils. They found wrong-size clamps in the cabin overhead, allowing the harness to lie on structure. Other clamps were attached to fluid lines in "butterfly" technique that could allow clamps to slip from their original positions and chafe the wires. Many block, strap or zip ties were broken. NAVAIR suggests using approved tie (lacing) to replace broken strap ties used for secondary support to hold open wire harnesses together. Connectors were corroded, had loose wires, or were strap-tied to hydraulic lines, which can induce chafing. Connectors not being used were found "bagged" in plastic bags, which promotes condensation [Read the story and look at the photos in the article, "Smokin'!," in the winter 2002/2003 issue.--Ed.]

The team at this squadron also found two engineering issues: wire routing and chafing that cause the harness to be pulled into the structure at several flight stations (522, 544, and 566) and an AFCS closet near the No. 2 generator that is a natural stepping spot for maintainers. The problem with this item is the harness, connectors and hardware are pushed down onto the underlying servos and hydraulic tubing.

Three segments of wire-inspection-technique training are done in conjunction with the material assessment, opportunity allows the squadron maintainers to see the problems found, learn how to prevent them in the future, and produce a more reliable and safe aircraft.

The first segment explains MIL-W-5088: how it relates to the aircraft and to the NAVAIR 01-1A-505 manual. It also gives examples of discrepancies to look for while doing maintenance or zonal inspections, as well as the benefits of these steps and preventive maintenance.

The second segment shows the photos taken during the assessment, allowing maintainers to identify and discuss the problems found. They get a "What's wrong with this picture?" approach.

The third segment is a "hands on" session to show maintainers correct techniques to do a thorough wiring inspection.

Critique sheets are handed out after every session, and that feedback has shown that the training "opened their eyes." Most feel the photos that show problems in their own aircraft were effective tools and made a big impression. One pilot who attended the training said, "This was one of the best and only presentations I've seen on how to preflight electrical wiring."