AD 2002-16-15

[Federal Register Volume 67, Number 163 (Thursday, August 22, 2002)]
[Rules and Regulations]
[Pages 54333-54336]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 02-20269]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NM-387-AD; Amendment 39-12854; AD 2002-16-15]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 777 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to certain Boeing Model 777 series airplanes, that requires 
modification of the supports for the wire bundles of the fuel quantity 
indicator system (FQIS), and follow-on actions, if necessary. The 
actions specified by this AD are intended to prevent chafing of the 
FQIS wiring on surrounding structures and systems. Such chafing could 
result in exposure of the bare conductor in close proximity to 
structures or other electrically conductive return paths, and potential 
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: Effective September 26, 2002.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of September 26, 2002.

ADDRESSES: The service information referenced in this AD may be 
obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, 
Washington 98124-2207. This information may be examined at the Federal 
Aviation Administration (FAA), Transport Airplane Directorate, Rules 
Docket, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of 
the Federal Register, 800 North Capitol Street, NW., Suite 700, 
Washington, DC.

FOR FURTHER INFORMATION CONTACT: John Vann, Aerospace Engineer, 
Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification 
Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone 
(425) 227-1024; fax (425) 227-1181.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) to include an airworthiness 
directive (AD) that is applicable to certain Boeing Model 777 series 
airplanes was published in the Federal Register on July 25, 2001 (66 FR 
38588). That action proposed to require modification of the supports 
for the fuel quantity indicator system (FQIS) wire bundles.

Comments

    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.

Request To Withdraw Proposed Rule

    One commenter states that the change proposed by the FAA has 
already been addressed by the manufacturer, per the release of the 
service bulletins referenced in the proposed rule that specify 
inspecting the in-tank wiring and revising the installation to enhance 
the wire separation from the in-tank structure. The commenter adds 
that, in testing where there was the potential for wire chafing from 
fuel sloshing and vibration, and during inspections, wire chafing was 
not found. The commenter states that chafed fuel quantity indicator 
system (FQIS) wiring, in combination with certain wiring or component 
failures, resulting in a potential ignition source, is improbable 
because of the safety design features that preclude such an occurrence. 
The commenter notes several reasons that the actions in the proposed 
rule are not necessary. First, the FQIS processor on Model 777 series 
airplanes is designed to meet electrical unit intrinsic safety levels, 
per the manufacturer's requirements. Second, the FQIS wiring has an 
outer insulation jacket, then a double-braided shield for protection, 
and each wire has its own insulation jacket. Third, for 70 percent of 
the distance from the processor to the wing spar, the FQIS wiring has a 
spatial separation from other airplane wiring. Fourth, the in-tank 
wiring conductor is nickel-plated, which, per in-service data, is 
proven to be resistant to fuel tank corrosion.
    The FAA infers that the commenter wants the proposed rule 
withdrawn. We do not agree. We have conducted many inspections of the 
fuel tanks on Model 777 series airplanes, and have found that the 
current wiring installation design is highly sensitive to wiring 
installation quality, such that the level of installation quality 
control necessary to prevent chafing is unrealistic. In addition, other 
factors such as fuel sloshing, airplane flexure, inertial loads, and 
fuel tank maintenance can cause the wiring to move into positions where 
chafing can occur. The modifications specified in the referenced 
service bulletins provide the necessary improvements to prevent chafing 
of the

[[Page 54334]]

FQIS wiring. Additionally, although the commenter stated that chafed 
wiring, in combination with certain wiring or component failures, would 
not result in a potential ignition source, we do not agree. The design 
features of the FQIS cannot ensure that, over the lifetime of the 
airplane, sufficient energy will not cause electrical arcing from 
entering the fuel tank.
    The same commenter asks that, if the proposed rule is adopted as 
final, it be changed to reference subsequent revisions of the 
referenced service bulletins for accomplishment of the specified 
actions.
    We do not agree with the commenter. An AD may only refer to service 
documents that are submitted and approved by the Office of the Federal 
Register for ``incorporation by reference.'' In order for operators to 
use later revisions of the referenced document (issued after the 
publication of the AD), either the AD must be revised to refer to the 
specific later revisions, or operators must request approval for the 
use of them as an alternative method of compliance with this AD under 
the provisions of paragraph (c) of this AD. No change to the final rule 
is necessary in regard to the previous comments.

Extend Compliance Time

    One commenter asks that the compliance time specified in the 
proposed rule be extended from 24 to 48 months. The commenter states 
that the airlines should be allowed to schedule incorporation of the 
modifications at a convenient heavy maintenance check if the specified 
safety procedures are in place and no evidence of chafing is found 
during testing or incorporation of the modifications.
    We do not agree with the commenter. The commenter provides no 
technical justification for increasing the compliance time as 
requested. Further, the areas where the wiring concerns being remedied 
by this AD are regularly exposed to flammable fuel vapors. Arcing in 
the tank can cause ignition of these flammable fuel vapors. In light of 
this, and since the unsafe condition addressed by this AD is a 
significant safety issue, we have determined that the compliance time 
of 24 months, as proposed, is warranted.
    In developing an appropriate compliance time for the actions 
required by this AD, we considered not only those safety issues, but 
the manufacturer's recommendations, parts availability, and the 
practical aspect of accomplishing the modifications within an interval 
paralleling normal scheduled maintenance for the majority of affected 
operators. In light of all of these factors described previously, we 
consider 24 months to be an appropriate compliance time wherein safety 
will not be adversely affected. No change to the final rule is 
necessary in this regard.

Eliminate Reporting Requirement

    One commenter asks that the reporting requirement included in 
paragraph (b) of the proposed rule be eliminated. The commenter states 
that at the time it accomplished the specified modifications, the 
referenced service bulletins did not include formal procedures or steps 
for inspection of the damaged wire. Therefore, the commenter did not 
include those steps in its internal documentation and cannot compile 
the information for the reporting requirement. The commenter notes that 
to comply it would have to re-inspect the wiring that has already been 
modified on all affected airplanes. This would include unscheduled fuel 
tank entries, which would not take place during a normal maintenance 
visit and would have a significant financial impact on the airlines.
    We partially agree with the commenter, but we do not agree to 
eliminate paragraph (b) of the final rule. However, we agree that if 
operators have accomplished the modifications required by paragraph (a) 
of the final rule, they should not have to re-enter the fuel tank to 
obtain the information necessary for the reporting requirement 
submission. Therefore, we have revised paragraph (b)(2) of the final 
rule to require submission of a report of findings from the previously 
completed fuel tank modification within 60 days after the effective 
date of this final rule.

Explanation of Change to Final Rule

    The FAA finds that the follow-on actions (Replacement and Reporting 
of Damaged Wiring), as specified in paragraph (b) of this AD, were 
inadvertently omitted from the Summary section of the proposed rule. 
Those actions have been included in the Summary section of this final 
rule for clarification. We also have changed the heading for paragraph 
(b) of the final rule to specify ``Follow-On Actions,'' in lieu of 
``Replacement and Reporting of Damaged Wiring,'' to better define the 
actions specified in paragraph (b) of this final rule.

Conclusion

    After careful review of the available data, including the comments 
noted above, the FAA has determined that air safety and the public 
interest require the adoption of the rule with the changes previously 
described. The FAA has determined that these changes will neither 
increase the economic burden on any operator nor increase the scope of 
the AD.

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 
will be affected by this AD, that it will take approximately the number 
of work hours per airplane displayed in the table below to accomplish 
the required 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
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                                                  Number of                              Number of
                                                  work hours   Parts cost   Estimated       U.S.      Estimated
            Boeing service bulletin                  per          per        cost per    airplanes     cost to
                                                   airplane     airplane     airplane     affected    U.S. fleet
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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
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    Service Bulletins 777-28-0012 and 777-28-0016 both address center 
fuel tank (CFT) wiring improvements and require CFT entry. Operators 
should note that concurrent incorporation of these two service 
bulletins would

[[Page 54335]]

minimize tank entries and would be a cost savings (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 table above are based on 
assumptions that no operator has yet accomplished any of the 
requirements of this AD action, and that no operator would accomplish 
those actions in the future if this 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. These figures typically do not include incidental costs, such as 
the time required to gain access and close up, planning time, or time 
necessitated by other administrative actions.

Regulatory Impact

    The regulations adopted herein will 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 final rule does not have federalism 
implications under Executive Order 13132.
    For the reasons discussed above, I certify that this action (1) is 
not a ``significant regulatory action'' under Executive Order 12866; 
(2) is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979); and (3) 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 final evaluation has been prepared for this action 
and it is contained in the Rules Docket. A copy of it may be obtained 
from the Rules Docket at the location provided under the caption 
ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends 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:

2002-16-15  Boeing: Amendment 39-12854. Docket 2000-NM-387-AD.

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

    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 potential electrical 
arcing and explosion in the fuel tank in the event of an additional 
wiring failure outside the fuel tank, accomplish the following:

Modifications

    (a) Within 24 months after the effective date of this AD, 
complete the actions required by paragraphs (a)(1), (a)(2), or 
(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 the 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 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 the service bulletin.

Follow-On Actions

    (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. Then submit a report of damaged wire findings to 
Service Bulletin Engineering, Boeing Commercial Airplane Group, P.O. 
Box 3707, Mail Stop 2H-37, 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 AD 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 were accomplished 
before the effective date of this AD, it is not necessary to re-
enter the fuel tanks to conduct inspections. Based on records 
collected during the previous modifications, submit the report 
within 60 days after the effective date of this AD. The report must 
include the date the modifications were done; any problems recorded 
when doing the modifications; a description of where the problems 
were found, if recorded; and a point of contact and telephone 
number.

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

[[Page 54336]]

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.

Incorporation by Reference

    (e) The modifications shall be done in accordance with Boeing 
Special Attention Service Bulletin 777-28-0012, dated September 2, 
1999; Boeing Special Attention Service Bulletin 777-28-0016, dated 
April 27, 2000; and Boeing Special Attention Service Bulletin 777-
28-0021, dated April 27, 2000; as applicable. This incorporation by 
reference was approved by the Director of the Federal Register in 
accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be 
obtained from Boeing Commercial Airplane Group, P.O. Box 3707, 
Seattle, Washington 98124-2207. Copies may be inspected at the FAA, 
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington; or at the Office of the Federal Register, 800 North 
Capitol Street, NW., Suite 700, Washington, DC.

Effective Date

    (f) This amendment becomes effective on September 26, 2002.

    Issued in Renton, Washington, on August 5, 2002.
Vi Lipski,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 02-20269 Filed 8-21-02; 8:45 am]
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