Wiring & Electrical Problems Are Dominant Dangers For Regulators

Recent regulatory activity coming out of the Federal Aviation Administration (FAA) shows that more than two-thirds of the safety-related items fall into three of 13 categories of action.

The pattern of activity shows where the FAA is focusing its attention, and where operators may wish to devote resources in the form of added attention, intensified inspections and maintenance. A review of 57 recent regulatory actions presented in this publication shows that in-flight firefighting capability, fuel system safety, and electrical wiring and component safety comprise some 68 percent of significant FAA regulatory activity since last October (see ASW, Oct. 27, 2003). In these three categories, wiring and electrical component safety issues dominated, with some 80 percent more regulatory activity - as an indicator of regulators' concern - than with fuel system safety, the runner-up category. This tabulation does not include all regulatory activity; it involves turbine-powered aircraft with six-passenger capability and above, and their cargo equivalents.

There is some crossover. Much of the fuel system safety activity (chafing, arcing, etc.) deals with electrical components (pump wiring, connectors, fuel quantity measuring circuits). Thus, overall, faulty wiring in fuel systems and elsewhere in the aircraft is the predominant trigger for regulatory action. In culling through the airworthiness directive (AD) and related activity, judgement has been applied to best assign each action to the appropriate risk category. The pattern shows that catastrophic structural failure or uncontained engine malfunctions pale in comparison to the threat of fire and explosion, at least as indicated in the regulatory.

The pattern of regulatory activity reinforces unrequited recommendations from the National Transportation Safety Board (NTSB). The elimination of explosive vapors in fuel tanks is on the NTSB's "Most Wanted" list of aviation safety improvements, precisely because the hunt for all potential ignition sources has not succeeded, and as evidenced by this recent regulatory activity to stamp out ignition sources. The NTSB also has called for improved wiring separation standards, and the contribution of chafing to the potential for electrical arcing is mentioned repeatedly in these recent regulatory initiatives.

Of interest, the pattern of regulatory activity does not match that of service difficulty reports (SDR). According to contributing editor Alex Richman, landing gear and engine problems vastly outnumber wiring-related reports (more than 700 to 19) in his consulting company's SDR database. This difference results from a look at 12 months of recent SDR activity involving big jets and FAA severity level "5" for items frequently associated with accidents and incidents.

"The ADs relate to past occurrences," Richman said. "SDRs portend emerging threats." He maintains that the continued delay in implementing the FAA's expanded SDR system is "bad for the further advancement of safety." (See ASW, Jan. 5)

Contributing editor John Sampson also mentioned the need for moving ahead with an improved SDR system in his assessment of the situation:

"This regulatory activity is in the main a process of rectification of actual - not perceived future - deficiencies that can lead to the development of unsafe conditions. From the point of view of cost, lost utilization, accidents, reputation and modification, the ideal would be for the designers and manufacturers to get it right in the first place. That seems to be unachievable and, notwithstanding the ongoing review of the FAA's certification practices, the never-ending 'fix' proceeds apace.

"If the airworthiness regulatory spectrum was considered to extend from polishing and enhancing safety to righting grievous deficiencies, the center of gravity of activity appears to be greatly weighted toward the latter.

"Following on from one of the safest years on record (see ASW, Jan. 5), this assessment might be considered unduly harsh. However, when considering that most regulatory activity stems from accidents, incidents or discoveries, maybe it isn't.

"Perhaps the process of find/then fix is the only engine available to move 'data-driven' safety. We should hope that the long awaited SDR initiative may help to streamline that locomotion."

Kent Hollinger, chairman of the Aging Transport Systems Rulemaking Advisory Committee (ATSRAC), takes a more optimistic view. He's particularly positioned to comment, given the ATSRAC's focus on wiring in old jets and the dominance of wiring-related issues in the latest regulatory activity.

"The designers and manufacturers do strive to 'get it right in the first place,' as witnessed by the continuing improvements in design standards and best practices. The industry is much more knowledgeable today than in the past, and this new knowledge is put into each new design. A review of reliability and safety data of past and present designs readily confirms this. With respect to 'righting grievous deficiencies,' my view is that we are continuing to apply new lessons learned to the best design data available from a previous time, for the further enhancement of safety."

Hollinger is one of a growing number of industry experts who believe that wiring should be considered a "system," with status and attention equal to that of avionics, hydraulics, flight controls, powerplants and such (see ASW, Feb. 3, 2003). The recent regulatory activity supports his contention. Hollinger, tel. 703/883- 5573; Richman, tel. 902/423-5155; Sampson, e-mail safety@iasa-intl.com

The article below is from Air Safety Week.