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Wiring Safety-A Slipping Priority-Air Safety Week

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Sat July 19 2003, 02:56 AM
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Wiring Safety-A Slipping Priority-Air Safety Week
Wiring Safety - A Slipping Priority

Note: Pay particular attention to the section entitled 'Constraining the scope' as it is especially relevant to sr111.

It likely will take nearly two and a half years for recommendations on wiring safety developed by a government-industry task force to be published to the industry as a notice of proposed rulemaking (NPRM).

The elapsed time illustrates how the issue of wiring safety has devolved from rush to red tape as the airline industry continues to hemorrhage red ink.

The Aging Transport Systems Rulemaking Advisory Committee (ATSRAC) has developed a broad range of inspection and regulatory initiatives, for both large and small transport aircraft, but the time it will take to put them into force is slipping (see ASW, July 14). When ATSRAC was first formed in 1999, senior Federal Aviation Administration (FAA) officials were urging ATSRAC members to move with alacrity, to hasten their deliberations. Now, the forces of bureaucratic formalism have slowed the effort in a process akin to sand thrown into the gearbox.

The delays heighten uncertainty for operators, in terms of what they will be expected to do, and how much time they will have to do it.

Sources say the declining priority accorded to wiring safety would be reversed overnight if a major wiring-related disaster occurred, such as the arcing-stoked in-flight fire that downed Swissair Flight 111 in 1998. The planned stately progression of the anticipated NPRM, for example, would be scrapped instantly. Moreover, a deadly wiring- related accident would facilitate the cost-benefit calculation needed to justify the ATSRAC's proposed wiring inspections. In the cold logic of cost-benefit, the costlier the program, the greater the number of demonstrated deaths that are needed to show the "benefits." The estimation of lives saved is based on accidents avoided - which requires accidents in the first place.

In some respects, the greater time being taken could result in a clearer, simpler and more straightforward program for manufacturers and operators to implement. That is, if certain uncertainties are resolved.

Keep in mind the two primary tasks that are coming. The first is a one-time cleaning and inspection of three high priority areas: cockpit wiring, electronics and equipment (E&E) bay wiring, and power feeder cables. This program goes by the acronym CEEPF. The second coming mandate is the enhanced zonal analysis program (EZAP). It will involve detailed visual inspections of aircraft wiring, zone-by-zone in the airplane (see ASW, July 15, 2002 box). EZAP involves detailed visual inspections (DVI), which will be more demanding than general visual inspectors (GVI) that have been the industry norm for years. DVI is short of intrusive inspections, but the limitation stems from the lack of reliable nondestructive test (NDT) technology for wiring. Numerous NDT approaches are in development as a result of the heightened interest in wiring safety. EZAP could impose industry-wide costs on the order of a quarter-billion dollars or more, although that number is "soft," depending upon how much of the wiring is included in the final EZAP mandate.

Keep in mind the populations of aircraft involved: large transport aircraft (LTA), involving those carrying more than 30 passengers, and small transport aircraft (STA), those carrying 6-30 passengers. Visual and intrusive inspections of the wiring in aircraft from both the LTA and STA populations have yielded similarly sobering results: inadequate clearance to structure and wire degradation over time featuring prominently in the inspection outcomes (see ASW, Jan. 27). The inclusion of STA stems from a National Transportation Safety Board (NTSB) recommendation following the fatal Oct. 25, 1999, crash of a Learjet Model 35 carrying golf professional Payne Stewart (see ASW, Dec. 4, 2000). The accident airplane was 23 years old and the NTSB called upon the FAA to include airplanes in this size category.

The forthcoming NPRM will outline the CEEPF and EZAP for large aircraft. Similar inspection requirements for small aircraft will follow. Consider the LTA and STA efforts as moving on parallel paths, STA activity following some 2-3 years behind the LTA.

Schedule slippage

For the large aircraft, ATSRAC delivered its report to the FAA in August 2002. As of last October, FAA officials were saying they planned to issue the NPRM in September 2003, a delay from an earlier plan to issue the NPRM in May 2003. At the latest July 10 ATSRAC meeting, FAA officials said they planned to issue the NPRM in January 2005. In the nine months that have elapsed since the October ATSRAC meeting, the NPRM publication schedule has slipped 16 months.

Instead of receiving the NPRM this September, the industry instead will be invited to comment on draft advisory circulars that will be incorporated into the NPRM.

Work slippage

Given that a final rule must be issued not more than 16 months after the comments period closes on the NPRM - which is estimated to be in April 2005 - the final rule would be issued not later than August 2006. Assuming that the effective date of the final rule would be the same, work would start in earnest at that point.

This revised schedule portends a significant change to the work plan envisioned by FAA officials last October (see ASW, May 5). Work would begin 32 months later under the new plan. Among the principal differences in the October 2002 and the July 2003 plans:

Operators will have five years rather than three years to complete the one-time CEEPF inspections.
Manufacturers will have two years rather than one year to develop EZAP.
Operators will have less time to incorporate EZAP into their maintenance programs.
The latest plan lumps all aircraft into one group of those more than five years old. The earlier plan prioritized the EZAP inspections in an "oldest first" to "youngest later" schedule. This modification may simplify scheduling. For example, an operator could have a B757 aircraft 5, 10 and 15 years old, thereby falling into three scheduling and completion timelines under the October 2002 plan.
Under the new plan, inspections may start earlier for some younger airplanes, although the oldest planes may present the greatest threat, given the findings of greater wire degradation with more time in service.
Complicating factors
Under the new plan, the clock starts ticking for the CEEPF inspections on day one. What guidelines do operators follow to complete these inspections? Note that under the previous plan, CEEPF inspections started later, allowing a window for the development of instructions to carry out the work. ATSRAC executive director Charles Huber conceded at the July 10 meeting that the absence of time to prepare CEEPF guidance could be "a weakness in the plan."

For example, what constitutes the cockpit wiring? Is it the wiring forward of the bulkhead, or must wiring that terminates in the cockpit be inspected all the way back to the other end? To be sure, the digital flight data recorder (DFDR) lodged in the aft area of the airplane would be included in this concept. One suggested approach might define cockpit wiring as all the wiring between the vertical plane of the forward pressure bulkhead and the vertical plane of the cockpit door. This definition would include wiring behind all cockpit panels (instrument panels, circuit breaker panels, etc.) and below the cockpit floor (i.e., not just the wiring that is visible walking into the cockpit).

E&E bay wiring also needs to be defined, since some of the wiring under the cockpit floor might be included in the definition of E&E bay wiring. E&E bay wiring also varies widely among various aircraft designs (e.g., widebody vs. narrowbody), and some designs have multiple electrical power centers. As for power feeder cables, it might be reasonable to define their starting point at the generator terminals and extending to the individual bus terminals, otherwise one has defined the entire wiring system of the airplane.

Under the new plan, if manufacturers take all of the 24 months to develop EZAP, operators have just 12 months to incorporate the new regimen into their maintenance programs. But if the manufacturers take more than 24 months, the operators won't have a year. Remember, the operators' revised maintenance programs incorporating EZAP must be approved by the FAA. If the manufacturers slip in developing EZAP, the operators could potentially find themselves out of compliance with the new requirements. The operators face penalties, but not the manufacturers.

ATSRAC has recommended that as the manufacturers complete their EZAP protocols by model, the operators incorporate them sooner. Indeed, the ATA favors this approach in order to minimize the downstream risk of schedule slippage and the attendant out-of-compliance exposure.

Constraining the scope

The issue of wiring installed for post-manufacture modifications represents a major challenge. Thousands of supplemental type certificates (STCs) have been issued - some to the manufacturers but mostly to third parties (e.g., repair stations) - for such add-on features as logo lights or in-flight entertainment (IFE) systems. Document-ation of the wiring associated with the third party STCs particularly is incomplete, if not nonexistent. The cost to repair stations to conduct an EZAP-type analysis of every STC is formidable, if not prohibitive. Whether to include or exempt STCs from EZAP was the subject of vigorous debate during ATSRAC's meeting this time last year (see ASW, July 15, 2002).

The plan as now constituted strips existing STCs from the EZAP process. This means, for example, that IFE wiring installed in the cabin per an STC granted to a third party would not necessarily come under the EZAP mandate (although in some cases the wiring installed for a cabin-wide IFE system may equal the amount of wiring in the rest of the airplane).

The problem is in justifying EZAP for all STCs. Including the cost of evaluating all existing STCs tips the scale - costs outweigh the estimated benefit. As a result, ATSRAC is considering the inclusion of a limited number of STCs - those issued to original equipment manufacturers (OEMs), and some third party STCs, notably those involving passenger-to- cargo conversions and STCs involving "high density" wiring (another definitional swamp that needs to be drained).

The cost-benefit hurdle may be higher for the 6-30 seat aircraft. Given the $3 million statistical value of a life, preventing one fatal accident for aircraft in this size range could save $18-$90 million, as compared to preventing the loss of a 100-seat aircraft and $300 million worth of lives saved. The whole CEEPF/EZAP effort for small aircraft may never be mandated if the potentially costly program saves so few lives.

In this respect, the required cost-benefit locks FAA officials into the "tombstone" approach to safety for which they have often been criticized. It takes accidents to justify action.