Enhanced Airworthiness Program for Airplane Systems/Fuel Tank Safety (EAPAS/FTS), 63364-63414 [E7-21434]

Agencies

• Federal Aviation Administration
• DEPARTMENT OF TRANSPORTATION

[Federal Register Volume 72, Number 216 (Thursday, November 8, 2007)]
[Rules and Regulations]
[Pages 63364-63414]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E7-21]



[[Page 63363]]

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Part III





Department of Transportation





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Federal Aviation Administration



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14 CFR Parts 1, 21, 25 et al.



 Enhanced Airworthiness Program for Airplane Systems/Fuel Tank Safety 
(EAPAS/FTS); Final Rule

Federal Register / Vol. 72, No. 216 / Thursday, November 8, 2007 / 
Rules and Regulations

[[Page 63364]]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Parts 1, 21, 25, 26, 91, 121, 125, and 129.

[Docket No.: FAA-2004-18379; Amendment Nos. 1-60, 21-90, 25-123, 26-0, 
91-297, 121-336, 125-53, 129-43]
RIN 2120-AI31


Enhanced Airworthiness Program for Airplane Systems/Fuel Tank 
Safety (EAPAS/FTS)

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: This final rule amends FAA regulations for certification and 
operations of transport category airplanes. These changes are necessary 
to help ensure continued safety of commercial airplanes. They improve 
the design, installation, and maintenance of airplane electrical wiring 
systems and align those requirements as closely as possible with the 
requirements for fuel tank system safety. This final rule organizes and 
clarifies design requirements for wire systems by moving existing 
regulatory references to wiring into a single section of the 
regulations specifically for wiring and by adding new certification 
rules. It requires holders of type certificates for certain transport 
category airplanes to conduct analyses of their airplanes and make 
necessary changes to existing Instructions for Continued Airworthiness 
(ICA) to improve maintenance procedures for wire systems. It requires 
operators to incorporate ICA for wiring into their maintenance or 
inspection programs. And finally, this final rule clarifies 
requirements of certain existing rules for operators to incorporate ICA 
for fuel tank systems into their maintenance or inspection programs.

DATES: These amendments become effective December 10, 2007.

FOR FURTHER INFORMATION CONTACT: If you have technical questions about 
the certification rules in this action, contact Stephen Slotte, ANM-
111, Airplane & Flight Crew Interface, Federal Aviation Administration, 
1601 Lind Avenue, SW., Renton, WA 98057-3356; telephone (425) 227-2315; 
facsimile (425) 227-1320, e-mail steve.slotte@faa.gov. If you have 
technical questions about the operating rules, contact Fred Sobeck, 
AFS-308, Aircraft Maintenance Division, Federal Aviation 
Administration, 800 Independence Avenue, SW., Washington, DC 20591; 
telephone: (202) 267-7355; facsimile (202) 267-7335, e-mail 
frederick.sobeck@faa.gov. Direct any legal questions to Doug Anderson, 
Office of Regional Counsel, Federal Aviation Administration, 1601 Lind 
Avenue, SW., Renton, WA 98057-3356; telephone (425) 227-2166; facsimile 
(425) 227-1007, e-mail Douglas.Anderson@faa.gov.

SUPPLEMENTARY INFORMATION:

Authority for This Rulemaking

    The FAA's authority to issue rules regarding aviation safety is 
found in Title 49 of the United States Code. Subtitle I, Section 106 
describes the authority of the FAA Administrator. Subtitle VII, 
Aviation Programs, describes in more detail the scope of the agency's 
authority.
    This rulemaking is promulgated under the authority described in 
Subtitle VII, Part A, Subpart III, Section 44701, ``General 
requirements.'' Under that section, the FAA is charged with promoting 
safe flight of civil aircraft in air commerce by prescribing minimum 
standards required in the interest of safety for the design and 
performance of aircraft; regulations and minimum standards in the 
interest of safety for inspecting, servicing, and overhauling aircraft; 
and regulations for other practices, methods, and procedures the 
Administrator finds necessary for safety in air commerce. This 
regulation is within the scope of that authority because it 
prescribes--
     New safety standards for the design of transport category 
airplanes, and
     New requirements necessary for safety for the design, 
production, operation, and maintenance of those airplanes, and for 
other practices, methods, and procedures relating to those airplanes.

Contents

I. Executive Summary
II. Background
    A. Summary of the NPRM
    1. The Proposed Rule
    2. Related Activities
    B. Differences Between the NPRM and the Final Rule
    C. Summary of Comments
III. Discussion of the Final Rule
    A. Overview
    B. Design Approval Holder (DAH) Requirements (part 26)
    1. Requirements To Develop ICA
    2. Changes to Location of Design Approval Holder Requirements
    3. Interaction Between New Design Approval Holder Requirements 
and Part 21
    4. Compliance Dates
    5. The Design Approval Holder Compliance Plan
    6. Defining the Representative Airplane
    7. Impact on Operators
    8. EZAPs Already Completed
    9. Wire Inspections
    10. Protections and Cautions
    11. Alignment of EWIS and Fuel Tank ICA
    12. Approval of ICA
    13. Rule Applicability
    14. Non-U.S. Manufacturers
    15. General Comments About Design Approval Holder Requirements
    16. Airplanes Excluded From Design Approval Holder and EWIS 
Operating Requirements
    C. Electrical Wiring Interconnection System (EWIS) Certification 
Rules (part 25 subpart H)
    1. New Subpart for EWIS
    2. The Definition of EWIS (Sec.  25.1701)
    3. Functions and Installation: EWIS (Sec.  25.1703)
    4. Systems and Functions: EWIS (Sec.  25.1705)
    5. System Separation: EWIS (Sec.  25.1707)
    6. System Safety: EWIS (Sec.  25.1709)
    7. Component Identification: EWIS (Sec.  25.1711)
    8. Fire Protection: EWIS (Sec.  25.1713)
    9. Electrical Bonding and Protection Against Static Electricity: 
EWIS (Sec.  25.1715)
    10. Accessibility Provisions: EWIS (Sec.  25.1719)
    11. Protection of EWIS (Sec.  25.1721)
    12. Flammable Fluid Shutoff Means: EWIS (Sec.  25.1727)
    13. Powerplant and APU Fire Detection System: EWIS (Sec.  
25.1731)
    14. Fire Detector Systems, General: EWIS (Sec.  25.1733)
    15. Engine, Nacelle, and APU Wiring
    16. Designated Fire Zones
    17. Goal of the New Wiring Subpart
    18. Harmonization
    D. Instructions for Continued Airworthiness: EWIS (Sec.  25.1729 
and Appendix H)
    1. Requirements for EWIS ICA
    2. ICA as a Single Document
    3. Standard Wiring Practices Manuals
    4. Mandatory Replacement Times
    5. Wire Identification Method Information
    6. Electrical Load Data
    E. Continued Airworthiness and Safety Improvements Subparts for 
Operating Rules (parts 91, 121, 125, 129)
    1. Establishment of New Subparts
    2. Continued Airworthiness Subparts and Airworthiness Directives
    3. Type and Scope of Requirements
    F. Operating Requirements for EWIS (parts 121 and 129)
    1. Requirements for Maintenance and Inspection Program Revisions
    2. ICA Developed by Design Approval Holders
    3. Different Requirements for Existing and Future Designs
    4. ICA for Alterations
    5. Alaska Operations
    6. EWIS Inspections
    7. Non-U.S. Registered Airplanes
    8. Taking Airplanes Out of Service
    9. Training
    10. Reporting Requirements
    G. Operating Requirements for Fuel Tank Systems (parts 91, 121, 
125, and 129)

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    1. Requirements for Maintenance and Inspection Program Revisions
    2. Airplanes Excluded From Fuel Tank System Operating 
Requirements
    3. Change in Operator Compliance Date for Auxiliary Fuel Tank 
ICA
    4. Original Configuration and Auxiliary Fuel Tanks
    5. Inspection and Maintenance Program Terminology
    H. Regulatory Evaluation
    1. Engine Costs
    2. Wiring System Safety Analysis for Engines
    3. Labor Rates
    4. The Regional Airplane Fleet
    5. Measure of Effectiveness
    6. Operational Impacts
    7. Training Costs
    8. Costs for EZAP Analysis and Inspection of Engines
    9. Engine Costs of Sec.  25.1362
    10. Wire Labeling Costs
    11. Additional Certification and Operator Costs
    12. Previous Rulemaking
    13. Relevance to the Current Fleet
    14. Accidents Indirectly Initiated by EWIS
    I. Harmonization Changes to Transport Category Certification 
Rules (Part 25)
    1. FAA/JAA (Joint Aviation Authority) Harmonization
    2. Circuit Protective Devices (Sec.  25.1357)
    3. Precautions Against Injury (Sec.  25.1360)
    4. Electrical Supplies for Emergency Conditions (Sec.  25.1362)
    5. Electrical Appliances, Motors, and Transformers (Sec.  
25.1365)
    J. Additional Certification Rule Changes (part 25)
    1. Rules Changed To Accommodate Subpart H
    2. Electrical Equipment and Installations (Sec.  25.1353)
IV. Regulatory Notices and Analyses
V. The Amendments

I. Executive Summary

    Safety concerns about wiring systems in airplanes were brought to 
the forefront of public attention by a midair explosion in 1996 
involving a 747 airplane. Ignition of flammable vapors in the fuel tank 
was the probable cause of that fatal accident, and the most likely 
source was a wiring failure that allowed a spark to enter the fuel 
tank. All 230 people aboard the airplane were killed. Two years later, 
an MD-11 airplane crashed into the Atlantic Ocean, killing all 229 
people aboard. Although an exact cause could not be determined, the 
presence of resolidified copper on a portion of a wire of the in-flight 
entertainment system cable indicated that wire arcing had occurred in 
the area where the fire most likely originated.
    Investigations of those accidents and later examinations of other 
airplanes showed a collection of common problems. Deteriorated wiring, 
corrosion, improper wire installation and repairs, and contamination of 
wire bundles with metal shavings, dust, and fluids (which would provide 
fuel for fire) were common conditions in representative examples of the 
``aging fleet of transport airplanes.''
    The FAA has concluded that current maintenance practices do not 
adequately address wiring components, wiring inspection criteria are 
too general, and maintenance instructions do not describe unacceptable 
conditions, such as improper repairs and installations, in enough 
detail.
    With this final rule we are introducing new maintenance, 
inspection, and design criteria for airplane wiring to address 
conditions that put transport airplanes at risk of wire failures, 
smoke, and fire. We are adding requirements for type certificate 
holders and applicants for type certificates and supplemental type 
certificates to analyze the zones of their airplanes for the presence 
of wire and for the likely accumulation of contaminant materials. This 
final rule also requires them to develop maintenance and inspection 
tasks to identify, correct, and prevent wiring conditions that 
introduce risk to continued safe flight. We are requiring that these 
tasks be included in new Instructions for Continued Airworthiness for 
wiring and that they be compatible with Instructions for Continued 
Airworthiness for fuel tank systems. The EWIS ICA must not conflict 
with the ICA for fuel tanks, and must avoid duplication and redundancy. 
Too frequent disturbance to electrical wiring by repeated moving, 
pulling, and flexing of the wire bundles will induce unnecessary stress 
on the wiring and its components, which in turn could lead to 
degradation, expedited aging, and failures. Thus it is important that 
redundant tasks and unnecessary disturbances to the electrical wiring 
be minimized. We are amending Title 14 Code of Federal Regulations 
(CFR) parts 91, 121, 125, and 129 operating rules to require operators 
of transport category airplanes to incorporate maintenance and 
inspection tasks for wiring into their regular maintenance programs and 
we are clarifying existing requirements for fuel tanks.\1\ We are 
creating a new subpart of part 25 to contain the majority of the 
certification requirements for airplane wiring, including new rules to 
improve safety in manufacture and modification. Finally, we are 
creating a new part 26 for design approval holder requirements relating 
to continued airworthiness and safety improvements and new subparts in 
parts 91, 121, 125, and 129 for the same types of requirements for 
operators.
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    \1\ We are not amending 14 CFR part 135 because presently there 
are only 20 airplanes with sufficient passenger or payload capacity 
to be affected by this rule that fly in part 135 operations. Should 
part 135 be amended to permit widespread usage of these larger 
transport category airplanes, we may extend the operating 
requirements of today's rule to part 135 at that time.
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    Accompanying this final rule are guidance materials in the form of 
advisory circulars (AC), which present one way, but not the only way, 
to comply with specific parts of these regulations.
    One of the ACs presents a suggested curriculum for electrical 
wiring interconnection system (EWIS) training. Existing Sec.  121.375 
requires that certificate holders or anyone performing maintenance have 
a training program. This requirement ensures that anyone determining 
the adequacy of maintenance work (including inspectors) is fully 
informed about the procedures and techniques involved and is competent 
to perform them. AC 120-94 provides guidance for complying with Sec.  
121.375 as it applies to EWIS maintenance and inspection. In AC 120-94 
we provide a suggested training program to address the informational 
needs of the various people who come in contact with airplane EWIS, and 
we encourage operators to include this training voluntarily. While the 
Aging Transport Systems Rulemaking Advisory Committee (ATSRAC) had 
recommended some form of EWIS training be required for anyone likely to 
come into contact with EWIS, we have determined the associated cost 
would be unduly burdensome. There are 11 other ACs accompanying this 
rule which provide guidance on different requirements contained here. A 
few of them have been revised for clarification. In those instances, 
this will be noted in section III. Otherwise, except for minor 
editorial changes, the guidance accompanying this rule is being 
published in the same form in which it was proposed and will not be 
discussed here.
    Since the Notice of Proposed Rulemaking (NPRM), the National 
Transportation Safety Board (NTSB) has issued Safety Recommendations A-
06-29 through -35 pertaining to fires on one particular model of 
regional jet. In the 6 months between October 2005 and March 2006, 
there were a total of 6 fires on regional jets. A seventh fire occurred 
prior to that 6-month period. The NTSB stated that, in addition to the 
danger posed by the fires, 2 of the incident airplanes temporarily lost 
all flight displays. The NTSB's investigation

[[Page 63366]]

revealed that all of the fires originated from the same electrical 
component--an electrical contactor located in the avionics compartment 
beneath the floor of the captain's seat. The fires were caused by 
moisture-induced short circuits between the electrical terminals of the 
contactors. We have issued airworthiness directives (AD) to correct 
this unsafe condition. However, if the requirements in this final rule 
had been in effect, the type of failure that caused these 7 fires would 
not have occurred. This is because several of the new requirements 
directly address design issues that led to the fires. This final rule 
is meant to proactively address wiring conditions existing in the 
transport airplane fleet that we now know affect safe flight and can be 
detected, corrected, or prevented.
    We express present value benefits and costs using a 7% discount 
rate. The total estimated benefits of this final rule, $801 million 
($388 present value) over a 25-year period, are comprised of 
operational benefits and safety benefits. The operational benefits are 
estimated at $506.3 million ($237.5 million present value). The safety 
benefits are estimated at $294.6 million ($150.6 million present 
value). This final rule will prevent a portion of fatal and non-fatal 
incidents and accidents while decreasing the impact that EWIS 
discrepancies have on airline operations.
    The estimated total cost of this final rule is $416 million ($233 
million present value) over 25 years. The majority of these costs 
($292.2 million, or $147.6 million present value) will be borne by 
operators. The remainder of the projected costs will be borne by 
aircraft and engine manufacturers, and, to a much lesser extent, the 
FAA Oversight Offices.

II. Background

A. Summary of the NPRM

1. The Proposed Rule
    On October 6, 2005 (70 FR 58508), the FAA published in the Federal 
Register the Notice of Proposed Rulemaking (NPRM) entitled Enhanced 
Airworthiness Program for Airplane Systems/Fuel Tank Safety (EAPAS/
FTS), which is the basis of this final rule.
    In that NPRM, we proposed development of Instructions for Continued 
Airworthiness (ICA) for wiring systems and subsequent incorporation of 
those ICA into operators' maintenance programs. We also proposed 
alignment of the compliance times for operators to incorporate wire and 
fuel tank system ICA into their maintenance programs.
    We proposed changes in the certification rules to require more 
attention during the design and installation of airplane systems to 
conditions that could compromise wire safety and accessibility. And we 
proposed a new part 25 subpart that would be dedicated to current and 
new regulations about airplane wiring systems.
    If you would like more details about the proposal, you can get a 
copy by following the instructions under the Availability of Rulemaking 
Documents heading at the end of this preamble.
2. Related Activities
    On July 12, 2005, the FAA published in the Federal Register a 
statement of policy for future management of the shared responsibility 
between design approval holders (DAH) and operators in achieving 
certain types of safety objectives. That stated policy is reflected in 
the requirements of this final rule for DAHs to develop ICA for 
airplane wiring systems.
    Also published in the July 12, 2005 Federal Register was a 
disposition of comments on a previous notice to extend the date for 
operators to comply with special maintenance requirements for fuel tank 
systems. That date was extended from December 6, 2004 to December 16, 
2008.
    On July 7, 2006, we published notice in the Federal Register 
stating that, although we had originally proposed to align compliance 
times for operator incorporation of ICA for wiring and for fuel tanks, 
we later found it impractical to do so. This notice notified operators 
that their compliance date for incorporation of fuel tank ICA is still 
December 16, 2008.
    Twelve draft ACs on different aspects of the rule accompanied the 
NPRM and were made available for public comment at the same time. On 
November 8, 2005, the comment period for the ACs was extended to 
February 3, 2006, so that it would align with the comment period for 
the NPRM.

B. Differences Between the NPRM and the Final Rule

    We have revised the numbering for 14 CFR part 25 subpart H 
Electrical Wiring Interconnection Systems (EWIS). We did this to 
harmonize as much as possible with the planned European Aviation Safety 
Agency (EASA) version of these rules. As discussed later, the design 
approval holder requirements proposed in the NPRM as subpart I are now 
contained in new part 26, again to harmonize more easily with the 
regulatory structure of other national airworthiness authorities. We 
also have made some changes to the compliance planning sections of 
those rules. In response to comments, we have increased the compliance 
time for the design approval holder requirements to 24 months from the 
effective date of this rule. We have increased the time for operator 
compliance with the EWIS requirements to 39 months from the effective 
date of this rule. Because our regulatory process exceeded the time we 
had originally planned for issuance of this rule, it is no longer 
practical to align the operator compliance dates for the EWIS ICA with 
those for fuel tanks. Coordination of the timing of the maintenance 
tasks within those ICA is still desirable and possible, so that aspect 
of our proposal remains unchanged in the final rule. We have, however, 
extended the date for operators to submit ICA for auxiliary fuel tanks 
to the FAA Oversight Office.
    We have removed some airplanes from the exclusion lists of the DAH 
requirements and the operating rules. This was either because they were 
already excluded as a result of the definition of the affected 
airplanes or because we have reconsidered the rationale for certain 
exclusions. We have also made other, minor, changes in wording to the 
proposed rules for the purposes of clarification or harmonization. We 
discuss all of the changes in section III of this preamble.

C. Summary of Comments

    The FAA received 39 comment letters about the proposed rule and 
guidance material. The comments covered a wide spectrum of topics and a 
range of responses, which we discuss more fully below. There was much 
support for the general intent of the rule and the guidance material. 
There were also requests for changes and for clarification.

III. Discussion of the Final Rule

A. Overview

    This rule is a result of years of study, data gathering, and 
collaboration with industry. It has been developed as a solution to the 
problem of wire contamination and wire damage on airplanes, which can 
result in system failures, smoke, and fire, and can threaten continued 
safe flight.
    Examinations by the Aging Systems Task Force of representative 
airplanes from the fleet of aging transports revealed wiring that was 
deteriorated, corroded, improperly installed and repaired, and 
contaminated with materials such as metal shavings, dust,

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and fluids.\2\ The NTSB, as well as working groups of the FAA, 
industry, and other Civil Aviation Authorities, found these conditions 
to be common across the fleet, not just isolated instances of poor 
maintenance. While systems have always been subject to careful scrutiny 
of their safety and reliability during the certification process, the 
wires that connect those systems had been considered appropriately 
cared for when fitted and maintained according to standard industry 
practices.
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    \2\ Transport Aircraft Intrusive Inspection Project final report 
dated December 29, 2000.
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    Now we know that airplane wiring needs more attention. It needs to 
be considered as a discrete system, and given the same careful scrutiny 
as other systems. The design of wiring systems is important for 
creating safe separation from other wires and systems and protecting it 
from damage. Inspection and maintenance is important in uncovering and 
repairing wire damage and preventing buildup of contaminants that can 
cause damage and that also provide fuel for fire. Wire must be 
inspected regularly and contaminant buildup must be prevented.
    In considering the problems found on transport category airplanes, 
we explored various alternatives. One alternative was to do nothing. 
But the result of that approach would be a continuation of incidents 
and accidents caused by deteriorated wiring systems. Once we knew there 
was a problem affecting safe flight, doing nothing was not really an 
option. We could have asked for voluntary support. But voluntary 
programs in the past have not always resulted in complete 
participation, and a voluntary program could not guarantee the level of 
safety we want to ensure. Accordingly, we decided to develop a rule to 
correct potential safety problems with airplane wiring, and to require 
compliance of all those whose participation is necessary to achieve 
that goal.
    This rule enlists the aid of design approval holders in assessing 
the wiring on their airplanes and in developing inspection and 
maintenance tasks that operators can use to maintain wire safety. It 
requires operators to incorporate into their inspection and maintenance 
programs tasks for maintaining wire safety that are based on those 
developed in accordance with requirements. It introduces new 
certification rules for wire separation, identification, system safety, 
protection from damage, access, and other aspects of wire safety. It 
creates a new subpart in the certification rules for wire certification 
so that the many existing requirements are more easily found. It also 
requires that design approval holders align inspection and maintenance 
tasks for wiring with those for fuel tank systems, to avoid duplication 
and to ensure that the most rigorous task is accomplished. As an 
example, if the EWIS ICA calls for a general visual inspection of a 
certain wire and the fuel tank ICA calls for a detailed inspection of 
the same wire, the general visual inspection task would be removed from 
the EWIS ICA and the detailed inspection would be retained in the fuel 
tank ICA, identified as both a fuel tank task and an EWIS task.

B. Design Approval Holder (DAH) Requirements (Part 26)

    For design approval holders this final rule differs from the 
proposal in the following four ways.
     The physical location of the rule has changed, from the 
proposed location in part 25, subpart I, to a new part 26.\3\
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    \3\ Since the comments refer to the NPRM, however, the 
commenters' original references are retained, including references 
to proposed ACs.
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     The compliance date has been changed from December 16, 
2007, to 24 months after the effective date of the rule.
     Two changes were made to the compliance plan requirement.
     The definition of the ``representative airplane'' has been 
clarified.

We have also made minor wording revisions to section 26.11 for 
clarification. They do not change the requirements.
1. Requirements To Develop ICA
    As discussed above, this rule introduces requirements for design 
approval holders (DAH) to assess their airplanes in relation to wiring. 
The assessment must be performed with an enhanced zonal analysis 
procedure (EZAP), which is outlined in a part-25-series advisory 
circular accompanying this rule entitled AC 25-27 ``Development of 
Transport Category Airplane Electrical Wiring Interconnection Systems 
Instructions for Continued Airworthiness Using an Enhanced Zonal 
Analysis Procedure.'' This AC was originally titled AC 120-XX ``Program 
to Enhance Aircraft Electrical Wiring Interconnection System 
Maintenance.'' The material contained in that proposed AC is now 
presented in two separate ACs. Guidance for carrying out an EZAP 
analysis, as required in the new parts 25 and 26 regulations in this 
final rule, is presented in the newly titled No. 25-27 AC named above, 
which will be referred to in the rest of this document as the DAH EZAP 
AC. Guidance for the operator requirements will be presented in a 
separate 120-series AC titled ``Incorporation of Electrical Wiring 
Interconnection System (EWIS) Instructions for Continued Airworthiness 
into the Operator's Maintenance Program.''
    For each zone on the airplane that contains wiring, DAHs must 
develop maintenance and inspection tasks to prevent contaminant buildup 
on that wiring and maintain safety. They must then make those tasks 
available to operators in the form of ICA readily identifiable as 
pertaining to wiring. They must also assess those wiring ICA in 
relation to ICA for fuel tank systems to make sure there are no 
conflicts or redundancies between the two. The rule includes 
requirements for the DAH to submit a compliance plan to the FAA 
outlining how it intends to meet these requirements.
2. Changes to Location of Design Approval Holder Requirements
    In the NPRM, we noted that we had not decided on the final location 
of the continued airworthiness and safety improvements design approval 
holder requirements of part 25, subparts A and I. We requested comments 
on this issue, and received 7 comments on the rule location. Transport 
Canada and British Airways stated that they wanted the requirements in 
part 21. This was to keep the procedural requirements of the new 
subpart with the present procedural requirements of part 21 and out of 
the airworthiness standards parts of the regulations. EASA, Airbus, 
Boeing, Aerospace Industries Association, and the General Aviation 
Manufacturers Association stated that they wanted the requirements in a 
new part or in part 21. EASA said these requirements must be in a 
mandatory part of its system and CS (Certification Specifications) -25, 
its equivalent to our part 25, is not mandatory. Others who commented 
wanted to maintain part 25 as strictly an airworthiness standard.
    Based on these comments and on discussions with Transport Canada, 
EASA, and the Brazilian Agencia Nacional de Aviacao Civil, we decided 
to create a new part 26 and move the enabling regulations out of part 
25 and into part 21--Certification Procedures for Products and Parts. 
We did this for several reasons.
    First, moving these requirements to a new part keeps part 25 as 
strictly an airworthiness standard for new transport category 
airplanes. This is important because it maintains

[[Page 63368]]

harmonization and compatibility among the United States, Canada, and 
the European Union regulatory systems. Second, integrating the 
requirements into part 21 improves the clarity of how the part 26 
requirements will address existing and future design approvals.
    In creating the new part 26, we renumbered the previous sections of 
part 25, subpart I, and we incorporated the changes discussed in this 
preamble. A table of this renumbering follows:

 Table 1.--Relationship of Proposed Subpart I to Final Rules in Part 26
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                  Part 26                        Part 25, Subpart I
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Subpart A--General
    Sec.   26.1 Purpose and Scope.........  Sec.   25.1801(a) Purpose
                                             and definition.
    Sec.   26.3 Definitions...............  Sec.   25.1801(b) and
                                             25.1803.
    Sec.   26.5 Applicability Table.......  New.
Subpart B--Enhanced Airworthiness Program
 for Aging Systems
    Sec.   26.11 Electrical Wiring          Sec.   25.1805 Electrical
     Interconnection Systems (EWIS)          Wiring Interconnection
     Maintenance Program.                    Systems (EWIS) Maintenance
                                             Program.
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    As noted in the table above, we have added a new Sec.  26.5 to 
provide an applicability table that will facilitate identifying those 
provisions of part 26 that apply to affected persons at any given time. 
As we add subparts to part 26, we will update this table to identify 
the applicability of those new subparts. As with new subpart B of part 
26 in this final rule, we will specify the details of applicability for 
each new subpart in the new subparts themselves.
3. Interaction Between New Design Approval Holder Requirements and Part 
21
    It was our intent to treat those provisions of the requirements 
establishing standards for design changes and revisions to the ICA as 
airworthiness requirements. Adding a statement to the new Sec.  26.1(a) 
that the requirements of part 26 are airworthiness requirements clearly 
integrates these requirements with the procedures specified in part 21. 
The result of treating these requirements as airworthiness requirements 
is that any design changes that may be required by part 26 rulemaking 
become part of the type design of the aircraft. This makes clear that 
the full flexibilities allowed in part 21, such as equivalent level of 
safety findings and special conditions, may be applied. Also, we added 
Sec.  26.1(c) to make a distinction in part 26 between type 
certificates and supplemental type certificates. Typically, for 
interpreting part 21, reference to type certificates includes 
supplemental type certificates unless usage of that term clearly 
indicates otherwise. While the usage of those terms in part 26 is 
contrary to the usage in part 21, we did this to make clear 
distinctions in requirements within part 26.
    To address the change to ``Special retroactive requirements'' 
originally proposed in Sec.  25.2(d) and to fully integrate the new 
rule with part 21, we made four changes to part 21. First, Sec.  21.7 
replaces proposed Sec.  25.2(d) by establishing the applicability of 
continued airworthiness and safety improvement requirements. This 
section establishes the general applicability of part 26 to design 
approval holders, pending and future applicants for design approval, 
and type certificate holders and licensees for newly produced transport 
category airplanes.
    While Sec.  21.7 makes part 26 applicable to pending applications, 
Sec.  21.17(a) clarifies this applicability by adding part 26 to the 
exception list of those requirements of the subchapter that are not 
established by date of application for a type certificate but by date 
that the type certificate is issued.
    For changed products, in the case when the exceptions of Sec.  
21.101(b)(1), (2) or (3) apply, new Sec.  21.101(g) makes clear that, 
even if an applicant may use an early amendment to part 25, the 
applicant must still comply with any applicable provisions of part 26. 
For each applicable part 26 provision, an applicant may elect to comply 
with a corresponding amendment to part 25 that is issued on or after 
the date of the part 26 amendment. Under the normal application of 
Sec.  21.101, if the exceptions of Sec.  21.101(b) do not apply, the 
applicant would be required to comply with the latest amendments of 
part 25 in lieu of the requirements of part 26.
    Sections 21.31 and 21.50 are revised to make it clear that the 
Airworthiness Limitations section of the ICA is part of the type design 
and that changes to the ICA generated under part 26 must be made 
available as part of the total ICA.
    These changes to part 21 do not change or add any new requirements 
to those proposed in the NPRM. Rather, they clarify the relationship 
between existing part 21 and new part 26.
4. Compliance Dates
    Several commenters proposed changes to the DAH compliance dates for 
subpart I (now part 26) requirements. The proposal would have required 
DAHs of existing airplanes to submit ICA for approval to the FAA 
Oversight Office by December 16, 2007. This was based on an expected 
effective date of June 30, 2006 for the final rule, and would have 
allowed DAHs 18 months to complete compliance. The proposed operator 
requirements would have allowed operators 12 months from the date DAHs 
completed their ICA to incorporate EWIS tasks into their maintenance 
program. The compliance date for operators (again based on an expected 
final rule effective date of June 2006) was December 16, 2008.
    Avions de Transport Regional (ATR), Aerospace Industries 
Association and General Aviation Manufacturers Association (AIA/GAMA), 
General Electric (GE), and Boeing requested a longer compliance time 
for the DAH requirements. ATR specifically proposed 30 months because 
it said it will need to review and update all of its maintenance 
documentation. GE requested 36 months. Boeing and AIA/GAMA requested 
the compliance time for DAHs be increased to 24 months. Boeing and AIA/
GAMA noted that industry, through ATSRAC, originally identified 24 
months as the time needed to conduct the EZAP analysis for their 
existing airplane configurations. But the FAA has now proposed 
additional requirements, such as evaluating type certificate (TC) 
holder changes mandated by airworthiness directives (AD) and compliance 
plan activities. The commenters noted that the original schedule and 
resource analysis did not account for these additional activities. 
Additionally, Boeing and FedEx requested that the rule include required 
time periods for FAA review and approval activities involved in the 
compliance plans. Boeing and Airbus noted that the rules do not 
currently limit the amount of time the FAA will take to review and 
approve documents, which will negatively impact their compliance time. 
Boeing stated that most DAHs will require the full 90 days for 
developing a compliance plan, and will not initiate that plan until 
they obtain FAA approval. So to ensure that they have an appropriate 
time for compliance activities, they'll need FAA approval immediately, 
which is impractical.
    Boeing and AIA/GAMA also said that the hard compliance dates and an 
expected final rule issuance in early 2007 will leave DAHs with less 
than 12 months to comply with the subpart I requirements. Along with 
Airbus and GE, they requested that we revise the compliance dates to 
represent a number

[[Page 63369]]

of months after the effective date of the rule, rather than a hard 
date. AIA/GAMA noted that this approach would prevent our process and 
schedule for issuing the final rule from impacting DAH compliance 
dates.
    We agree with the commenters that additional time should be allowed 
for DAH compliance with 26.11. While we understand that ICA for EWIS 
have already been developed for a number of affected airplanes, we also 
understand that not all DAHs have begun this activity. In addition, as 
discussed later, DAHs that have already developed EWIS ICA may not have 
addressed the ``representative airplane'' configurations, as required 
by this rule. However, because DAHs would need to plan and coordinate 
with the FAA anyway, we do not believe the requirements to do so will 
significantly increase the amount of time needed to comply. In 
consideration of these factors, we believe that 24 months will allow 
sufficient time for DAHs to develop and submit the necessary compliance 
plan, draft data and documents, and final data and documents to show 
compliance with today's rule.
    We have made a minor revision to section 26.11(d)(3), (d)(4) and 
(d)(5). This is to clarify that the affected pending or future 
applicants must comply either by a date based on the effective date of 
the rule, or by the date of approval of the related certificate. Even 
though we specifically discussed the intent of these dates in the NPRM 
preamble, we believe that using the term ``approval of the 
application,'' which appeared in the proposal (in proposed Sec.  
25.1805(c)(3), (c)(4), and (c)(5)) indicating dates for compliance, may 
have caused confusion. So, we have replaced the term ``application'' 
with the term ``certificate'' in 26.11(d)(3), (d)(4) and (d)(5).
    We are not including FAA-required time periods for review and 
approval of the required compliance plans. Instead, expectations for 
FAA personnel have been defined in a new FAA order \4\ that directs the 
Aircraft Certification and Flight Standards Services in their roles and 
responsibilities for implementing these initiatives. The order includes 
expected times (6 weeks) for reviewing and approving DAH compliance 
plans, plans to correct deficiencies, and draft and final compliance 
data and documents. To facilitate implementation, we will also train 
affected personnel in their roles and responsibilities and provide in-
depth familiarization with requirements of the regulations and 
associated guidance. The FAA's Aviation Safety organization's recent 
registration as an ISO (International Organization for Standardization) 
-9001-compliant organization will also facilitate standardized and 
timely implementation of the review and approval process.
---------------------------------------------------------------------------

    \4\ Order 8110.26, ``Responsibilities and Requirements for 
Implementing Part 26 Safety Initiatives,'' will be released 
concurrently with this rule.
---------------------------------------------------------------------------

    Several operators also requested revisions to the DAH compliance 
dates, noting the potential adverse impact on them because of the time 
it could take for FAA review and approval. Air Transport Association 
(ATA) recommended that Sec.  25.1805(c)(1) (now 26.11(d)(1)) be 
rewritten to provide a reasonable period of time (90 days) for the 
necessary FAA review and approval activities. ATA noted that the amount 
of time the FAA will take to review and approve TC holders' EWIS/FTS 
ICA could reduce operator compliance time significantly. FedEx made 
similar comments and noted that compliance dates should acknowledge 
time for approval of compliance documents, distribution of those 
documents, operator planning for addressing the requirements, and final 
release of the changes in the operator's program. Royal Dutch Airlines 
(KLM) was also concerned about FAA review and approval impacting 
operators' compliance time and requested that the operator compliance 
date be one year after ICA are approved. Boeing, ATR and U.S. Airways 
also stated that the compliance time for the operational rules should 
be based on availability of needed data.
    Continental requested that operators be allowed 18 months rather 
than 12 months to comply. It said a thorough training program would be 
needed for maintenance personnel not familiar with wiring and its 
components. This would require additional effort by the operator not 
contemplated by simply having ICA incorporated into a maintenance task 
or inspection program. Additionally, Continental stated that contract 
maintenance personnel must also be trained for systems they maintain.
    The National Air Carrier Association (NACA) requested that 
operators have two years for compliance, dependent on DAHs complying 
with their requirements on time.
    Based on rationale the ATA provided for requesting the change, we 
infer that ATA would like additional time (90 days) added to the 
operator's compliance time rather than to the DAH's compliance time. 
While it is inappropriate to put requirements for the FAA in a rule 
applicable to DAHs, we have, as discussed previously, identified 
expectations for FAA review and approval (including timeframes) in an 
internal FAA order. The length of time to review plans, data, and 
documents depends largely on the quality of the submittals. Acceptable 
documents will take less time to review.
    We have structured the requirements of the DAH rule and developed 
complementary guidance to facilitate timely review and approval of DAH 
submittals (compliance planning, draft document reviews, etc.). We do 
agree, however, that a modest increase in operator compliance time 
would help ensure that operators are not impacted by the FAA review and 
approval process. We have revised the EAPAS compliance date for 
operators from 12 months to 15 months.
    Regarding the NACA request for a two-year compliance time, in the 
past we have imposed numerous maintenance program revision requirements 
through operational rules and ADs. Twelve months has been the typical 
compliance time for these changes and has been sufficient for operators 
to comply. The maintenance actions described in the maintenance program 
changes would be accomplished sometime later, as specified in the 
maintenance program. So operators will have sufficient time to plan and 
conduct the necessary EWIS training.
    On July 30, 2004, (69 FR 45936), we extended the Fuel Tank Safety 
Operational Rule compliance dates to December 16, 2008, for reasons 
outlined in that final rule. Because of the similar timelines for 
operator incorporation of the FTS and EAPAS maintenance actions into 
their programs, we had determined that aligning the compliance dates 
for the FTS and EAPAS maintenance program changes would allow operators 
to revise their maintenance program once to address both safety 
initiatives. However, given delays in issuing the EAPAS rulemaking 
proposal and the expectation for industry to have the FTS ICA developed 
for compliance with the EASA rule (December 2007) and the FAA rule 
(December 2008), we have determined that the benefits of aligning the 
FTS and EAPAS compliance dates are not substantial enough to justify 
further delay in implementing FTS maintenance actions. As previously 
discussed, we are not extending the FTS operational rule compliance 
date in this final rule.

[[Page 63370]]

5. The Design Approval Holder Compliance Plan
    As noted above, in the NPRM we contemplated submission of a 
proposed means of compliance, identifying all required submissions to 
the FAA. The NPRM proposed submission of--
     A project schedule identifying all major milestones.
     A detailed explanation of how the proposed means of 
compliance would be shown to comply if it differed from that described 
in advisory material.
     A proposal for submitting a draft of all compliance items 
no less than 60 days before the compliance due date.
     A proposal for how the approved ICA would be made 
available to affected persons (operators and others required to comply 
with this rule).
    The proposal stated that if the FAA notified the DAH of 
deficiencies in its proposed compliance plan or in its implementation 
of that plan, the DAH must submit a corrected plan to the FAA Oversight 
Office within 30 days. All of these compliance plan requirements were 
contained in proposed Sec.  25.1805(d) and (e).
    Airbus requested that Sec.  25.1805(d) and (e) be removed because, 
it said, these requirements are unnecessary. Airbus believes the only 
important compliance date is the final date for DAHs to submit the data 
and documents necessary to support operator compliance. Boeing 
recommended we remove the Sec.  25.1805(d)(3) requirement to identify 
deviations to methods of compliance identified in FAA advisory material 
because it does not agree that proposed methods of compliance should be 
compared to other methods. Instead, it said, they should be evaluated 
on their own merits.
    The FAA agrees that some provisions of proposed Sec.  25.1803(d) 
and (e) could be removed without adversely affecting our ability to 
facilitate TC holder compliance. Specifically, proposed paragraph 
(d)(3) would require TC holders to identify intended means of 
compliance that differ from those described in FAA advisory materials. 
While this is still a desirable element of any compliance plan, we have 
concluded that an explicit requirement is unnecessary and it is not 
included in this final rule. As with normal type certification 
planning, we expect that TC holders will identify differences and fully 
discuss them with the Oversight Office early in the compliance period 
to ensure that these differences will ultimately not jeopardize full 
and timely compliance. Because we believe that timely review and 
approval is beneficial and will save both DAH and FAA resources, the 
advisory material recommends that if the DAH proposes a compliance 
means differing from that described in the advisory material, the DAH 
should provide a detailed explanation of how it will demonstrate 
compliance with this section. The Oversight Office will evaluate these 
differences on their merits, and not by comparison with FAA advisory 
material.
    Similarly, proposed paragraph (e) contains provisions that would 
have authorized the Oversight Office to identify deficiencies in a 
compliance plan or the TC holder's implementation of the plan and 
require specific corrective actions to remedy those deficiencies. While 
we anticipate that this process will still occur in the event of a 
potential non-compliance, we have concluded that it is unnecessary to 
adopt explicit requirements to correct deficiencies and have removed 
them from the final rule. Ultimately, TC holders are responsible for 
submitting compliant EWIS ICA by the specified date. This section 
retains the requirements to submit a compliance plan and to implement 
the approved plan. If the Oversight Office determines that the TC 
holder is at risk of not submitting compliant EWIS ICA by the 
compliance date because of deficiencies in either the compliance plan 
or the TC holder's implementation of the plan, the Oversight Office 
will document the deficiencies and request TC holder corrective action. 
Failure to implement proper corrective action under these 
circumstances, while not constituting a separate violation, will be 
considered in determining appropriate enforcement action if the TC 
holder ultimately fails to meet the requirements of this section.
    Additionally, in reviewing the comment, we realized that the rule 
text could more clearly state our intent to allow DAHs flexibility to 
modify their approved plan if necessary. So the final text of proposed 
Sec.  26.11(f) has been modified to read ``each affected person must 
implement the compliance plan, or later approved revisions * * *.'' In 
response to Airbus' comment that the only important compliance date is 
the final date for DAHs to submit the data and documents, we must 
reiterate that we believe a compliance plan is important. The purpose 
of a 90-day compliance date for the compliance plan is to allow all 
parties to be informed about how the DAH will be meeting its 
requirements and to ensure that the all necessary data will be provided 
to the operators on time. Early development of a compliance plan will 
give assurance of development of all the necessary data in time for the 
operators to comply with their requirements.
6. Defining the Representative Airplane
    Boeing requested that we define in advance of the final rule which 
TC holder configuration changes mandated by ADs should be considered in 
the EZAP. Boeing and AIA/GAMA noted that the DAH must consider airplane 
configurations representative of each airplane model plus DAH-developed 
modifications mandated by AD. Boeing stated that because ADs are 
applicable to operators and not DAHs, and because most ADs are not 
applicable to all airplanes within a specific model range, it is 
difficult to define a representative airplane. Boeing does not believe 
the proposed Sec.  25.1805 (now Sec.  26.11) compliance time allows 
enough time to properly define the representative configuration.
    As previously discussed, we have increased the proposed DAH 
compliance time for a number of reasons, one of which was to allow 
sufficient time for the DAH to identify the representative 
configuration for each affected airplane model.
    As discussed in the NPRM, the purpose of the requirement to address 
all TC-holder-developed modifications mandated by AD is to make the 
EZAP as complete and accurate as possible. It would serve no purpose to 
require the TC holder to analyze an airplane configuration no longer in 
service because an AD has mandated its modification. Therefore, TC 
holders must assess all these modifications to determine whether they 
affect the results of the EZAP. Because TC holders own the design data 
for both the original configurations and these modifications, they are 
the only entities capable of performing these assessments. When TC 
holders develop AD-mandated modifications for airplanes still in 
production, they normally incorporate these same modifications into new 
airplanes. So this requirement imposes little additional burden for 
these airplanes. At the same time, we recognize that it would be 
unreasonable to require the TC holder to analyze modifications 
developed by third parties. Accordingly, this requirement is limited to 
TC-holder-developed modifications.
    In reviewing Boeing's comment, we recognized that the proposed 
definition of ``representative airplane,'' i.e., ``the configuration of 
each model series airplane that incorporates all variations of EWIS 
used on that series airplane * * *,'' could be interpreted in different 
ways. It could be interpreted as applying to all post-production

[[Page 63371]]

modifications, not just those mandated by AD and those DAH-developed 
modifications introduced into production. It could also refer to 
variations used for post-production modifications, as well as those 
used in production. Boeing correctly understands that we intended to 
require evaluation only of variations used in production and those 
post-production modifications mandated by AD. Section Sec.  26.11(b) 
has been revised to clarify this. For those design changes made in 
production for which the TC holder has issued service bulletins 
describing post-production equivalents, the ICA should identify those 
service bulletins with the corresponding production configurations. 
This will enable operators that have incorporated these service 
bulletins to determine that the ICA for the production modification 
also applies to them.
7. Impact on Operators
    Boeing asked that we separate the operational rule from DAH 
requirements, with a separate comment period, so that defined service 
information and associated costs can be evaluated by the operators. 
Boeing contended that consolidating DAH and operational requirements 
into one rulemaking action with one comment period prevents the FAA 
from obtaining accurate cost estimates and prevents operators from 
determining the true impact of the proposal on their operations. NACA 
also expressed concern that operators cannot know the full impact of 
this rule until DAHs develop the required ICA.
    We have decided against separating the operational rules from the 
DAH requirements. Separating the rules would not change the technical 
requirements contained in this final rule but would substantially delay 
implementation of the EAPAS safety initiative. Thus, it is essential to 
include both certification and operational requirements in the final 
rule to ensure maximum safety benefits to the flying public.
    In addition to issues of timeliness, we note that while some 
operators will not know the precise effects of the ICA developed by TC 
holders on their maintenance programs, they should have a good 
understanding of the nature and scope of the program from the NPRM and 
the guidance material provided in the DAH EZAP AC (AC No. 25-27). As 
discussed, both of these were derived from ATSRAC's recommendations, 
which operators played a major role in developing. In addition, since 
2004, multiple operators have been involved with several airplane 
manufacturers in developing EWIS ICA using the EZAP analysis described 
in the DAH EZAP AC. This has been accomplished by integrating EWIS ICA 
development into the airplane manufacturer's normal maintenance 
development program. Operators of the airplane model for which a 
maintenance program is being developed (or revised) are always involved 
in the development of that program. Therefore, these operators do know 
the impact of integrating these new EWIS ICA into their maintenance 
programs.
8. EZAPs Already Completed
    Boeing asked that we include a statement in the final rule 
indicating that EZAP analyses conducted prior to the effective date of 
the final rule, and resultant ICA, comply with subpart I (now part 26) 
requirements. Boeing questioned the statement that the proposed time 
frames are supported by experience gained by EZAPs already performed, 
when the NPRM did not discuss the acceptability of those analyses. It 
noted that several EZAP analyses were conducted using MSG-3 \5\ 
methods, which differ slightly from those contained in proposed AC 120-
XX (now the DAH EZAP AC, No. 25-27). Boeing noted that, for those 
cases, it must show the FAA Oversight Office how the previous analyses 
were conducted, make any necessary changes, obtain industry agreement, 
and have the FAA approve the resulting ICA.
---------------------------------------------------------------------------

    \5\ Air Transport Association (ATA) Maintenance Steering Group 3 
(MSG-3) is a document containing a logic process used by the 
airlines and manufacturers to develop scheduled maintenance programs 
for an airplane.
---------------------------------------------------------------------------

    We believe that work done before adoption of the rule will reduce 
the level of effort required for DAHs to comply with the rule. But we 
also recognize that some additional work may be necessary for DAHs to 
show compliance. For example, EWIS ICA may not have been aligned with 
FTS ICA or may not have been developed for the ``representative 
airplane'' as defined in the rule. Therefore previous work cannot 
automatically be considered compliant. Because we cannot say with any 
confidence that no more work will be required, we are not adopting 
Boeing's recommendation.
9. Wire Inspections
    The National Air Traffic Controllers Association (NATCA) called the 
proposal inadequate because it relies on enhanced zonal inspections to 
detect latent failures in the wiring system, and it said that zonal 
inspections detect only visible deteriorated wire.
    The commenter said that without periodic or real-time monitoring of 
airplane wiring, there is no way to predict a degraded state and 
prevent future wire failures. NATCA recommended that we include 
requirements for either continuous on-board detection of airplane 
wiring faults, such as that provided by system self-test features, or 
periodic maintenance tasks, to detect both visible and hidden 
degradation in the wiring system.
    The requirements adopted today do not prevent use of wire 
monitoring or fault detection technology. Multiple non-destructive 
inspection (NDI) tools and real-time monitoring techniques are being 
developed for use in aircraft wiring inspection. However, current NDI 
reflectometry technology is not yet mature enough for its use to be 
mandated by the FAA. Although real-time monitoring technology, such as 
arc fault circuit breaker technology, is further along in development, 
it too is not yet mature enough to address all circuit types. We expect 
that these technologies, when available, may be relatively more 
expensive than conventional methods, so the need for visual inspection 
of EWIS would remain even if this technology were widely available. We 
made no change based on this comment.
10. Protections and Cautions
    Boeing requested that we remove from subpart I (now part 26) the 
requirement to include ICA instructions for protection and caution 
information to minimize contamination and accidental damage during 
maintenance activities. It suggested this language should be added to 
the operating rule. Boeing considers the methods of protecting wiring 
during maintenance to be best determined by the maintenance provider 
and dependent on the type of maintenance activity underway. Boeing also 
noted that operators who have already developed protection schemes 
based on their experience will be required by the operational rules to 
replace this with the one provided by the TC holder. Boeing does not 
believe this is a positive step towards increased protection of EWIS.
    United Airlines stated its support for requiring airplane 
manufacturers to include specific recommendations for when and how to 
protect wire bundles from damage during different phases of 
maintenance.
    We infer that Boeing is referring to the requirement in 
H25.5(a)(1)(vi). That requirement applies both to new type certificates 
complying with Sec.  25.1729

[[Page 63372]]

(proposed as Sec.  25.1739) and existing type certificates complying 
with part 26. The requirement is consistent with ATSRAC's 
recommendations. These recommendations were based on recognition that 
the TC holder will have the best understanding of EWIS material 
properties and vulnerabilities, and will be in the best position to 
identify what protection and caution measures are needed. If operators 
have developed their own instructions, they may be used as alternatives 
or as supplements to those provided by the TC holder, if approved by 
their Principal Inspector (PI). We have provided guidance to the FAA 
field offices to allow for consideration of an operator's alternative 
to that approved by the FAA Oversight Office. We made no rule change 
based on this comment.
11. Alignment of EWIS and Fuel Tank ICA
    AIA/GAMA and GE requested that the last sentence of proposed Sec.  
25.1805(b) (now Sec.  26.11(b)), requiring minimization of redundant 
requirements between EWIS and fuel tank ICA, be deleted. The commenters 
stated that this is an economic and customer service issue beyond the 
scope of the FAA's safety interest.
    Boeing requested we include, within proposed Sec.  25.1805(b), the 
levels of alignment of FTS and EWIS maintenance actions that will be 
acceptable for compliance. While Boeing sees the benefit of eliminating 
redundant maintenance activities, it considers itself unable to 
determine how to show compliance with this requirement.
    Minimizing redundant requirements is not just an economic issue for 
operators. One of ATSRAC's findings is that repeated disturbance of 
EWIS during maintenance is itself a source of safety problems. 
Therefore, while ensuring that all necessary maintenance is performed, 
it is also our objective to minimize disturbance by eliminating 
redundant requirements. Too frequent disturbance to electrical wiring 
by repeated moving, pulling, and flexing of the wire bundles will 
induce unnecessary stress on the wiring and its components, which in 
turn could lead to degradation, expedited aging, and failures. Thus it 
is important that redundant tasks and unnecessary disturbances to the 
electrical wiring be minimized. Operators will review their maintenance 
tasks and coordinate with the DAHs to ensure that tasks are 
incorporated into their maintenance program for the highest level of 
safety and performed in the manner most suitable for their operation.
    As discussed earlier, Boeing and other TC holders have been 
required to develop ICA since 1981, and maintenance manuals even before 
that. In developing ICA, TC holders routinely review individual tasks 
to align them with other tasks being developed. This is done both to 
avoid redundancy and to eliminate confusing or conflicting instructions 
that could inadvertently lead to improper maintenance with unsafe 
consequences. The purpose of the requirement to align the ICA is no 
different. The intended ``levels of alignment'' are the same as would 
be expected for ICA developed in connection with original type 
certification. The MSG-3 and Maintenance Review Board (MRB) processes, 
with which Boeing and other affected TC holders are familiar, have the 
same objectives. The DAH EZAP AC, ``Development of Transport Category 
Airplane Electrical Wiring Interconnection Systems Instructions for 
Continued Airworthiness Using an Enhanced Zonal Analysis Procedure,'' 
No. 25-27, describes means of compliance that will achieve these 
objectives. It provides a step-by-step process to assist applicants in 
compliance with the electrical wiring interconnection system (EWIS) 
maintenance requirements. This process includes a step requiring an 
analysis of the related maintenance tasks to ensure that they are 
consolidated and/or aligned to maximize effectiveness and eliminate 
redundancies and duplications between the EWIS and fuel tank ICA.
    The airplane manufacturer will align the ICA requirements to the 
greatest extent possible. No change to the final rule is necessary.
12. Approval of ICA
    Boeing and AIA/GAMA requested further clarification of proposed 
Sec. Sec.  25.1739 (now Sec.  25.1729) and 25.1805(b) (now Sec.  
26.11(b)) requirements that ICA prepared in accordance with paragraph H 
25.5 of Appendix H be submitted to the FAA Oversight Office for 
approval. AIA/GAMA, Airbus, and FedEx recommended that EWIS ICA be 
accepted by the FAA, rather than approved, with the exception of any 
applicable airworthiness limitation items (ALI), which should be 
approved. The commenters were concerned that the proposed req