View Full Version : FAA Announces New Wiring Initiatives

The Guvnor
18th Aug 2001, 01:14
The Federal Aviation Administration (FAA) unveiled a broad new initiative designed to enhance the continued safety of aircraft wiring systems from their design and installation through their retirement.

The FAA based its Enhanced Airworthiness Program for Airplane Systems(EAPAS) on results from an intensive data-gathering effort on aircraft wiring systems done in cooperation with industry. EAPAS combines a variety of near- and longer-term actions into a plan to increase awareness of wiring system degradation, implement improved procedures for wiring maintenance and design, and spread that information throughout the aviation

The FAA's overall Aging Transport Non-Structural Systems program, an effort
begun in October 1998, is an expansion of the agency's Aging Aircraft Program. The systems program, modeled after the very successful aging structures program started more than a decade ago, looks into wiring systems (i.e., connectors, wiring harnesses, and cables) and is now reviewing mechanical systems.

The near-term elements of the EAPAS plan are designed to accomplish rapid safety improvements based on existing, fully analyzed data. These actions, which are now mostly complete, include:
- Essential corrective actions such as airworthiness directives
- Promoting adoption of better wiring maintenance procedures though a "lessons learned" document from aircraft manufacturers to operators
- New training and guidance materials for FAA inspectors and engineers
- Sharing information with industry and worldwide civil aviation authorities

Longer-term actions in the EAPAS plan are intended to "institutionalize" management of aircraft wiring systems by revising existing federal regulations concerning design, certification, maintenance and continued
airworthiness of aircraft wiring systems.

This effort would include:
- Proposing a Special Federal Aviation Regulation to mandate the development of an enhanced inspection program
- Proposing regulatory changes to enhance maintenance programs for systems
- Developing advisory materials that define an aging systems maintenance and training program
- Proposing changes to certification regulations to specifically address wiring systems

EAPAS' longer-term actions also will improve reporting and analysis of wire problems and foster research and development in the areas of arc fault circuit breakers, automated wire inspection tools, wire separation and wire

The full text of the EAPAS plan is available under the "Reports, Publications & Documents" section at: http://www.faa.gov/apa/newsroom.htm

Kermit 180
19th Aug 2001, 09:41
I saw a documentary a few years ago about kapton (?) wiring and how it could degrade but couldn't be inspected easily due to the way it was installed. This came about after the TWA crash and the Swissair MD11 crash. Aircraft most at risk of kapton wire fires were deemed to be older generation types such as the L1011 and classic 747 versions.


19th Aug 2001, 10:16
L1011 didnt use kapton

Kermit 180
19th Aug 2001, 10:19
It was definitely a L1011, being filmed in one of those aircraft 'grave yards', but perhaps time has degraded my memory. Perhaps they were using this particular L1011 as an example of old wiring? Apologies to L1011 people.


The Guvnor
19th Aug 2001, 12:43
Actually, the L1011 does use Kapton, but the wiring harnesses are better designed than those on other aircraft - especially McDonnell Douglas and Boeing.

Boeing now uses TKT - a sandwich of Teflon Kapton and Teflon - in its aircraft (though it does still use Kapton in "accessible" areas); whereas Airbus still use Kapton throughout their aircraft.

It's highly probable that as well as SR111, Kapton wire arc-tracking may well have caused the crash of SAA's Boeing 747 Combi Helderberg off Mauritius in November 1987.

For more information, check out www.iasa.com.au (http://www.iasa.com.au)

The Guvnor
24th Aug 2001, 18:38
Just received the following from Ed Block, who is one of the main wiring experts that has been exposing the risks of Kapton. Makes pretty chilling reading!

There has been a real war raging as of late with the FAA and I. After the two and a half years of inspecting aircraft, there was no question as to there being a major problem with the fleet's wiring. It was also determined that visual inspections were inadequate in discerning the most serious wire flaws (cracks). I thought that the war was over. The FAA told me in Jan 01 they
would be developing wire performance standards to alleviate the chance of any
future poor selections of wire.

Instead, the ATSRAC has just approved sending the development of wire performance testing to R&D for 3 more years. They are saying in effect that it is the installation, and not insulation. They are essentially saying if we
could keep those pesky mechanics off the aircraft, the wiring would last forever. This is an attempt to shift responsibility to the operators rather than the OEMs.

I have submitted comments to the ATSRAC Training Group I belong to, and the Head of Certification John Hickey. I have also been interviewed by USA Today and the Associated Press on these issues. This needs to be shouted from the roof tops. The wires going into the 777 (cross-linked Tefzel), are
the smokiest, most toxic, and flammable wires out there. They are as soft as butter at rated temperature. Why are these defective wires still allowed?

There are still no performance tests required by the FAA for wiring, even though they released the Aircraft Materials Fire Test Handbook on 6/1/00 which contained tests for arc tracking, smoke, flammability and toxicity of aircraft wiring (http://www.fire.tc.faa.gov/handbook.stm). Please help spread the word that there are more tests for seat-covers than the wiring that ignites fuel vapors, insulation blankets, and generates uncommanded inputs
into autopilots, and onto control surfaces.