Chafing,abrasion and short circuit arcing in the vitally important “Electrical Wiring Interconnect System” (EWIS) has been and continues to be a major concern. Chafing and abrasion can have a serious impact on the safe functioning of aircraft systems.

This problem was once thought to be an issue with older Part 25 aircraft with 20 years or more time in service (TIS). However documented reported mishaps are showing that even new or recently produced aircraft by the OEM / TC holder are also susceptible to wire chafe.

Aviation Week recently reported a story about recommendations made to the FAA and Brazil’s ANAC stemming from a November 2019 incident with a Republic Airways Embraer 175.   Part of the problem was chafed flight control system wires.

The Atlanta to La Guardia flight experienced an excessive un-commanded pitch-up just 4 minutes into the flight. The flight crew solved the problem and landed safely but two switches did not work due to chafed wire insulation.  The chafing was on the horizontal stabilizer actuator control electronics to the captain’s pitch-trim switch and autopilot/trim disconnect button.

Subsequently Republic have found nine aircraft with chafed wiring and according to the NTSB other unidentified operators have found issues as well.

This “simple” problem caused potential life threatening issues.  With so much life and treasure at stake OEM/MRO/FBO’s can no longer rely on “business as usual” approaches to maintaining wire/cable integrity.  Yes it has been changing as recognition has grown that wiring is a critical system on aircraft – the EWIS.

Part of the solution is to apply best in class protection to prevent wiring chafe. DTi Spring-Fast protective Edge Grommets coupled with Protect-Fast wire wrap.

Spring-Fast grommets in particular provide best-in-class wire chafe protection at half the installed cost of the old slow and costly nylon glued in grommets.

DTi products are ideally suited for installation on operational aircraft requiring a minimum of down time and are installed without messy adhesives or Toxic VOCs.

Source: Aviation Week