Final Rule: Enhanced Airworthiness Program for Airplane Systems/Fuel Tank Safety

Background

During the late 1990s, the FAA and industry determined they needed a better understanding of wire-related failures that could result in arcing, smoke in the cabin or flight deck, and sometimes even onboard fires. The Federal Aviation Administration’s (FAA) Enhanced Airworthiness Program for Airplane Systems (EAPAS), which was established in 2001, has been developing enhancements for continued safety of aircraft wiring systems from their design, installation, and maintenance throughout their operational life.

The EAPAS program led to a proposed rule in October 2005 that, for the first time, viewed aircraft wiring as important systems on their own. The rule proposed to revise current maintenance practices and specified other actions to address issues of aging and degradation in wiring.

The final rule, comprehensive in addressing all aspects of electrical wiring design, installation and maintenance for transport airplanes, was published on November 8, 2007. It is the result of recommendations made by industry groups working with the FAA and international authorities to increase the safety of airplane electrical wiring systems.

What the EAPAS Rule Specifies

The final rule makes regulatory changes pertaining to wiring systems and fuel tank systems in transport category airplanes. The rule:

• Requires Design Approval Holders to conduct analyses and develop Instructions for Continued Airworthiness (ICA) for wiring to improve maintenance procedures for wire systems. 
• Requires operators to incorporate ICA for wiring into their maintenance or inspection programs. 
• Clarifies requirements of certain existing rules for operators to incorporate ICA for fuel tank systems into their maintenance or inspection programs.

Effects of the EAPAS Rule

• Requirements for developing certification and maintenance instruction for airplane wiring will be more clearly defined and enhanced. They will be contained in a new subpart of Part 25 specifically devoted to wiring.
• The applicants of pending Supplemental Type Certificates (STC) and existing Type Certificate (TC) holders for transport airplanes with a maximum capacity of 30 or more passengers or a maximum payload capacity of 7,500 lbs. or more will provide ICA for wiring for their “representative” airplanes — i.e., the configuration of each model series that incorporates all the TC holder variations of wire systems used on that series.
• ICA for wiring for existing airplanes will be completed by 24 months after the effective date of the rule. 
• Applicants for approval of future design changes to affected transport airplanes must evaluate effects of proposed changes on the wiring ICA developed by the TC holder and develop revisions to the ICA to address those effects.
• ICA prepared in compliance with SFAR 88 will be reviewed to ensure compatibility with and avoid duplication of the new ICA for wiring.
• Operators under parts 121 and 129 will incorporate the wiring ICA in their maintenance/inspection programs by 39 months after the effective date of the rule, and update those programs as needed for subsequent modifications.
• By December 16, 2008, operators under Parts 91, 121, 125, and 129 will develop maintenance/inspection programs for fuel tank systems based on fuel tank system ICA developed by manufacturers under SFAR 88.
  • There are fewer than 20 such airplanes operating under part 135, so the FAA did not include them.
• Wire systems on transport category airplanes will be better designed, better maintained, and safer.
• Operators will be more easily able to incorporate these safety enhancements into their maintenance/inspection programs because their requirements have been aligned, where possible. 

Costs and Benefits

Total costs are estimated at $416 million ($233 million present value) over 25 years. Total benefits are estimated at $801 million ($388 million present value) over 25 years.

Source: FAA