[Federal Register Volume 66, Number 143 (Wednesday, July 25, 2001)]
[Proposed Rules]
[Pages 38588-38591]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-18473]


-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NM-387-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 777 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to certain Boeing Model 777 series 
airplanes. This proposal would require modification of the supports for 
the fuel quantity indicator system (FQIS) wire bundles. This action is 
necessary to prevent chafing of the FQIS wiring on surrounding 
structures and systems, which could result in exposure of the bare 
conductor in close proximity to structures or other electrically 
conductive return paths and a consequent possibility of electrical 
arcing and explosion in the fuel tank in the event of an additional 
wiring failure outside the fuel tank. This action is intended to 
address the identified unsafe condition.

DATES: Comments must be received by September 10, 2001.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2000-NM-387-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. Comments may be inspected at this 
location between 9 a.m. and 3 p.m., Monday through Friday, except 
Federal holidays. Comments may be submitted via fax to (425) 227-1232. 
Comments may also be sent via the Internet using the following address: 
[email protected]. Comments sent via fax or the Internet must 
contain ``Docket No. 2000-NM-387-AD'' in the subject line and need not 
be submitted in triplicate. Comments sent via the Internet as attached 
electronic files must be formatted in Microsoft Word 97 for Windows or 
ASCII text.
    The service information referenced in the proposed rule may be 
obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, 
Washington 98124-2207. This information may be examined at the FAA, 
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington.

[[Page 38589]]


FOR FURTHER INFORMATION CONTACT: Ed Hormel, Aerospace Engineer, 
Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification 
Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone 
(425) 227-2681; fax (425) 227-1181.

SUPPLEMENTARY INFORMATION:

Comments Invited

    Interested persons are invited to participate in the making of the 
proposed rule by submitting such written data, views, or arguments as 
they may desire. Communications shall identify the Rules Docket number 
and be submitted in triplicate to the address specified above. All 
communications received on or before the closing date for comments, 
specified above, will be considered before taking action on the 
proposed rule. The proposals contained in this action may be changed in 
light of the comments received.
    Submit comments using the following format:
     Organize comments issue-by-issue. For example, discuss a 
request to change the compliance time and a request to change the 
service bulletin reference as two separate issues.
     For each issue, state what specific change to the proposed 
AD is being requested.
     Include justification (e.g., reasons or data) for each 
request.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the proposed rule. All 
comments submitted will be available, both before and after the closing 
date for comments, in the Rules Docket for examination by interested 
persons. A report summarizing each FAA-public contact concerned with 
the substance of this proposal will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this action must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 2000-NM-387-AD.'' The postcard will be date stamped 
and returned to the commenter.

Availability of NPRMs

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules 
Docket No. 2000-NM-387-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    As a result of a 747-100 accident investigation, the FAA conducted 
an inspection of the fuel quantity indicator system (FQIS) wiring in a 
777-300 center fuel tank (CFT). This inspection identified several 
potential FQIS wire chafing concerns. Boeing 777-200 airplanes with 
increased capacity CFTs share the same CFT design and potential wire 
chafing concerns as the 777-300 airplanes. FQIS wiring on 777-200 and -
300 airplanes, which is routed through penetrations in the CFT spanwise 
beams and side body ribs, has inadequate clearance, excessive slack, 
and is unprotected from chafing and damage. Also, FQIS wiring secured 
by P-clamps mounted on flat bracket plates is exposed to chafing on the 
bracket plate edges and airplane structure. Fuel sloshing, vibration, 
and normal maintenance activity within the fuel tanks over the lifetime 
of the airplane increases the risk of chafing and damage to wire that 
is inadequately secured and protected. Chafed FQIS wiring, with bare 
conductor exposed, and in close proximity to structures or other 
electrically conductive return paths, is a potential ignition source 
when combined with certain FQIS wiring or component failures. This 
condition, if not corrected, could result in electrical arcing and 
explosion in the fuel tank.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Special Attention Service 
Bulletin 777-28-0012, dated September 2, 1999 (for Model 777-200 series 
airplanes), which describes procedures for replacement, with new 
brackets and seals, of the wiring support brackets for the FQIS wire 
bundles at the structural penetration points where the wire bundles 
enter the CFT.
    The FAA has reviewed and approved Boeing Special Attention Service 
Bulletin 777-28-0016, dated April 27, 2000 (for Model 777-200 and -300 
series airplanes), which describes procedures for modification of the 
FQIS wiring in the CFT by increasing the separation between wire and 
surrounding structures and systems, and by controlling the wire slack 
at clamping locations. The modification involves installing spacers on 
the FQIS wiring support brackets and standoffs, installing a clamp next 
to the grommet at each tank unit, and replacing the clamp filler O-
rings.
    The FAA has also reviewed and approved Boeing Special Attention 
Service Bulletin 777-28-0021, dated April 27, 2000 (also for Model 777-
200 and -300 series airplanes), which describes procedures for 
modification of the FQIS wiring in the main fuel tanks, also by 
increasing the separation between wire and surrounding structures and 
systems and by controlling the wire slack at clamping locations. The 
modification involves installing spacers on the FQIS wiring support 
brackets and standoffs, installing a clamp next to the grommet at each 
tank unit, and replacing the clamp filler O-rings.
    Accomplishment of the actions specified in each of the above-
referenced service bulletins is intended to adequately address the 
identified unsafe condition.

Explanation of Requirements of Proposed Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other products of this same type design, the 
proposed AD would require accomplishment of the actions specified in 
the service bulletins described previously, except as discussed below. 
The proposed AD also would require that operators report results of 
inspection findings to the manufacturer.

Differences Between Proposed Rule and Service Bulletins

    Operators should note that, although the service bulletins 
recommend accomplishing the modifications ``at a convenient maintenance 
opportunity when manpower and facilities are available,'' the FAA has 
determined that such an imprecise compliance time would not address the 
identified unsafe condition in a timely manner. In developing an 
appropriate compliance time for this AD, the FAA considered not only 
the manufacturer's recommendation, but the degree of urgency associated 
with addressing the subject unsafe condition, the average utilization 
of the affected fleet, and the time necessary to perform the 
modifications. In light of all of these factors, the FAA finds a 
compliance time of 24 months for completing the required actions to be 
warranted, in that it represents an appropriate interval of time 
allowable for affected airplanes to continue to operate without 
compromising safety.
    Operators should also note that, although the service bulletins do 
not give specific instructions for the disposition of any damaged wire 
encountered during the modifications, this AD would require that any 
damaged wire (i.e., chafed wire, or wire with exposed conductor, broken 
insulation, conductor, or shielding) must be replaced per the Boeing 
Standard Wiring Practices Manual D6-54446, Chapter 20, Section 10, 
Subject 11 (20-10-11), dated August 1, 1996, and any

[[Page 38590]]

damage reported to the Boeing Company.

Cost Impact

    There are approximately 266 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 75 airplanes of U.S. registry 
would be affected by this proposed AD, that it would take approximately 
the number of work hours per airplane displayed in the table below to 
accomplish the proposed modifications, and that the average labor rate 
is $60 per work hour. Required parts costs are also listed in the table 
below:

                                              Estimated Cost Impact
----------------------------------------------------------------------------------------------------------------
                                  Number of work                                  Number of U.S.
     Boeing service bulletin         hours per    Parts cost per  Estimated cost     airplanes    Estimated cost
                                     airplane        airplane      per airplane      affected      to U.S. fleet
----------------------------------------------------------------------------------------------------------------
777-28-0012.....................              38            $628          $2,908              23         $66,884
777-28-0016 (Group 1)...........              43             490           3,070              18          55,260
777-28-0016 (Group 2)...........              48             839           3,719              57         211,983
777-28-0021 (Work Package 1)....              30           1,058           2,858              75         214,350
777-28-0021 (Work Package 2)....              32           1,058           2,978              75         223,350
----------------------------------------------------------------------------------------------------------------

    Service Bulletins 777-28-0012 and 777-28-0016 both address CFT 
wiring improvements and require CFT entry. Operators should note that 
concurrent incorporation of these two service bulletins would minimize 
tank entries and would be a cost saving (33 work hours per airplane) to 
the operators because they would need to de-fuel, access, and close 
access to the CFT only once.
    The cost impact figures discussed in the above table are based on 
assumptions that no operator has yet accomplished any of the proposed 
requirements of this AD action, and that no operator would accomplish 
those actions in the future if this proposed AD were not adopted. The 
cost impact figures discussed in AD rulemaking actions represent only 
the time necessary to perform the specific actions actually required by 
the AD. The figures in the table above do not include incidental costs, 
such as planning time, or time necessitated by other administrative 
actions.

Regulatory Impact

    The regulations proposed herein would not have a substantial direct 
effect on the States, on the relationship between the national 
Government and the States, or on the distribution of power and 
responsibilities among the various levels of government. Therefore, it 
is determined that this proposal would not have federalism implications 
under Executive Order 13132.
    For the reasons discussed above, I certify that this proposed 
regulation (1) is not a ``significant regulatory action'' under 
Executive Order 12866; (2) is not a ``significant rule'' under the DOT 
Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 
and (3) if promulgated, will not have a significant economic impact, 
positive or negative, on a substantial number of small entities under 
the criteria of the Regulatory Flexibility Act. A copy of the draft 
regulatory evaluation prepared for this action is contained in the 
Rules Docket. A copy of it may be obtained by contacting the Rules 
Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 
part 39 of the Federal Aviation Regulations (14 CFR part 39) as 
follows:

PART 39--AIRWORTHINESS DIRECTIVES

    1. The authority citation for part 39 continues to read as follows:

    Authority: 49 U.S.C. 106(g), 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

Boeing: Docket 2000-NM-387-AD.

    Applicability: Model 777 series airplanes, certificated in any 
category, line numbers 1 through 266, inclusive.

    Note 1: This AD applies to each airplane identified in the 
preceding applicability provision, regardless of whether it has been 
modified, altered, or repaired in the area subject to the 
requirements of this AD. For airplanes that have been modified, 
altered, or repaired so that the performance of the requirements of 
this AD is affected, the owner/operator must request approval for an 
alternative method of compliance in accordance with paragraph (c) of 
this AD. The request should include an assessment of the effect of 
the modification, alteration, or repair on the unsafe condition 
addressed by this AD; and, if the unsafe condition has not been 
eliminated, the request should include specific proposed actions to 
address it.

    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent chafing of the fuel quantity indicator system (FQIS) 
wiring on surrounding structures and systems, which could result in 
exposure of the bare conductor in close proximity to structures or 
other electrically conductive return paths and a consequent 
possibility of electrical arcing and explosion in the fuel tank in 
the event of an additional wiring failure outside the fuel tank, 
accomplish the following:
    (a) Within 24 months after the effective date of this AD, 
complete the actions required by paragraphs (a)(1), (a)(2), and 
(a)(3) of this AD, as applicable.

Modification of Model 777-200 Center Fuel Tank Wiring

    (1) For Model 777-200 series airplanes identified in Boeing 
Special Attention Service Bulletin 777-28-0012, dated September 2, 
1999, modify the FQIS wire bundles (including removing the FQIS wire 
bundle support brackets at each spanwise beam penetration and 
replacing them with seals; removing the FQIS wire bundle support 
brackets from the side of the body rib; installing a grommet in the 
penetration hole; and replacing the bracket with two new brackets) 
in accordance with the Accomplishment Instructions of the service 
bulletin.

Modification of Model 777-200 and -300 Center Fuel Tank Wiring

    (2) For Model 777-200 and -300 series airplanes identified in 
Boeing Special Attention Service Bulletin 777-28-0016, dated April 
27, 2000, modify the supports for the FQIS wire bundles in the 
center fuel tank (including installing spacers on the FQIS wiring 
support brackets and standoffs; installing a clamp next to the 
grommet at each tank unit; and replacing the clamp filler O-rings), 
in accordance with the Accomplishment Instructions of that service 
bulletin.

Modification of Model 777-200 and -300 Main Fuel Tank Wiring

    (3) For Model 777-200 and -300 series airplanes identified in 
Boeing Special Attention Service Bulletin 777-28-0021, dated April 
27, 2000, modify the FQIS wire bundles in the main fuel tanks 
(including

[[Page 38591]]

installing spacers on the wiring support brackets and standoffs; 
installing a clamp next to the grommet at each tank unit; and 
replacing the clamp O-rings), in accordance with the Accomplishment 
Instructions of that service bulletin.

Replacement and Reporting of Damaged Wiring

    (b) If any damaged wiring is found during the performance of the 
modifications required by paragraph (a)(1), (a)(2), or (a)(3) of 
this AD, before further flight, replace the damaged wiring with new 
wiring in accordance with Boeing Standard Wiring Practices Manual 
D6-54446, Chapter 20, Section 10, Subject 11 (20-10-11), dated 
August 1, 1996. Submit a report of damaged wire findings to the 
Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 
98124-2207, at the applicable time specified in paragraph (b)(1) or 
(b)(2) of this AD. The report must include a description of any 
discrepancies found, the airplane serial number, and the number of 
landings and flight hours on the airplane. Information collection 
requirements contained in this regulation have been approved by the 
Office of Management and Budget (OMB) under the provisions of the 
Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et seq.) and have 
been assigned OMB Control Number 2120-0056.
    (1) For airplanes on which the modifications are accomplished 
after the effective date of this AD: Submit the report within 14 
days after performing the applicable modification required by 
paragraph (a)(1), (a)(2), or (a)(3) of this AD.
    (2) For airplanes on which the modifications have been 
accomplished prior to the effective date of this AD: Submit the 
report within 14 days after the effective date of this AD.

Alternative Methods of Compliance

    (c) An alternative method of compliance or adjustment of the 
compliance time that provides an acceptable level of safety may be 
used if approved by the Manager, Seattle Aircraft Certification 
Office (ACO), FAA. Operators shall submit their requests through an 
appropriate FAA Principal Maintenance Inspector, who may add 
comments and then send it to the Manager, Seattle ACO.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.

Special Flight Permits

    (d) Special flight permits may be issued in accordance with 
Secs. 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 
21.197 and 21.199) to operate the airplane to a location where the 
requirements of this AD can be accomplished.

    Issued in Renton, Washington, on July 19, 2001.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 01-18473 Filed 7-24-01; 8:45 am]
BILLING CODE 4910-13-P