[Federal Register Volume 68, Number 153 (Friday, August 8, 2003)]
[Rules and Regulations]
[Pages 47213-47216]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 03-19981]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2001-NM-232-AD; Amendment 39-13259; AD 2003-16-06]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747 Series Airplanes 
Equipped with General Electric CF6-45 or CF6-50 Series Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to all Boeing Model 747 series airplanes equipped with 
General Electric CF6-45 and CF6-50 series engines. This amendment 
requires an inspection to detect chafing of the fuel line or incorrect 
clearance between the fuel line and pneumatic duct insulation blanket; 
a fuel leak check and strut drain test; corrective action if necessary; 
replacement of the outboard strut fuel line coupling O-rings and 
retaining rings with new parts; replacement of the pneumatic duct boot 
with a new part; and, for certain airplanes, installation of a flame 
arrestor and drain line entry screens. The actions specified by this AD 
are intended to prevent leaking fuel line couplings, chafed fuel lines, 
restricted or clogged strut drain lines, migrating fluids or vapors 
toward ignition sources, and flashback of external flame into the 
strut; these conditions could result in an uncontained engine strut 
fire. This action is intended to address the identified unsafe 
condition.

DATES: Effective September 12, 2003. The incorporation by reference of 
certain publications listed in the regulations is approved by the 
Director of the Federal Register as of September 12, 2003.

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: Dan Kinney, Aerospace Engineer, 
Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification 
Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone 
(425) 917-6499; fax (425) 917-6590.

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 all Boeing Model 747 series 
airplanes equipped with General Electric CF6-45 and CF6-50 series 
engines was published in the Federal Register on January 29, 2003 (68 
FR 4398). That action proposed to require an inspection to detect 
chafing of the fuel line or incorrect clearance between the fuel line 
and pneumatic duct insulation blanket; a fuel leak check and strut 
drain test; corrective action if necessary; replacement of the outboard 
strut fuel line coupling O-rings and retaining rings with new parts; 
replacement of the pneumatic duct boot with a new part; and, for 
certain airplanes, installation of a flame arrestor and drain line 
entry screens.

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 Correct Service Bulletin Citations

    Two commenters state that there are typographical errors in two of 
the service bulletin citations specified in the section in the preamble 
titled ``Explanation of Relevant Service Information.'' The first 
commenter states that the reference to Boeing Service Bulletin 747-28-
2155 should be 747-71-2155. The second commenter states that the 
reference to Boeing Service Bulletin 747-36-2122 should be 747-54-2122. 
While the FAA agrees with these corrections and acknowledges that the 
service bulletin citations were incorrect in the proposed AD, that 
section of the preamble is not restated in the final rule.

Request To Clarify Certain Paragraphs

    One commenter asks that paragraph (e) of the proposed AD be 
changed, for clarification, to add that the fiberglass fabric pneumatic 
duct boot is replaced with a new, NOMEX fabric duct boot. We agree and 
have added the language requested by the commenter to paragraph (e) of 
this final rule.
    The same commenter asks that paragraphs (b) and (f) of the proposed 
AD be changed, for clarification, to add the term ``outboard'' to 
define which strut is affected by those paragraphs. We agree and have 
added the term requested by the commenter to paragraphs (b) and (f) of 
this final rule.

Replace Pneumatic Boot Only if Damage Found

    One commenter states that it performs the repetitive detailed 
visual inspections of the pneumatic duct boot at every 1C-check, with 
replacement of the duct boot if it is damaged. The commenter asks that 
it be allowed to continue to perform the inspections at every 1C-check, 
and replace the duct boot only if damaged, instead of replacing the 
duct boot at the time specified in paragraph (e) of the proposed AD. 
The commenter asks that its program be included as an alternative 
method of compliance (AMOC) to the proposed AD, if possible.
    We do not agree with the commenter. Early replacement of the 
original boot configuration with a NOMEX boot is critical to having a 
reliable seal in place. The flight-hour intervals used for maintenance 
checks may not ensure replacement of the original boot within 12 
months. However, if maintenance records indicate that the original boot 
has been replaced with the new NOMEX fabric part, it is not necessary 
to repeat that action. Paragraph (e)(2) of this final rule is a 
continuing requirement which specifies that whenever a damaged boot of 
the original boot configuration is found it must be replaced before 
further flight, or within 5 days following detection if there are no 
leaks. The commenter may submit substantiating data that support a 
request for an AMOC per paragraph (i) of this AD. No change to the 
final rule is necessary in this regard.

[[Page 47214]]

Request To Change Compliance Time

    Two commenters ask that the compliance time for the repetitive 
replacement of the O-rings and retaining rings, as specified in 
paragraph (d) of the proposed AD, be changed, as follows: One commenter 
states that it performs the repetitive replacement of the O-rings and 
retaining rings every 5 years.
    We infer that the commenter wants to continue the replacement every 
5 years, in lieu of the compliance time of every 21,000 flight hours or 
5 years, whichever is earlier (unless a coupling is disassembled).
    The same commenter states that it performs the fuel pressure leak 
check every 5 years when it replaces the O-rings and retaining rings, 
and would like to be allowed to continue at that interval in lieu of 
the 3-year interval specified in Boeing Service Bulletin 747-28-2230, 
dated September 30, 1999 (referenced in the proposed AD as the source 
of service information for accomplishment of the fuel leak check and 
strut drain inspection).
    We acknowledge that the service bulletin specified recommends 
repeating the leak check every 3 years; however, the proposed AD does 
not require repetitive fuel pressure leak checks; only a one-time check 
within 12 months after the effective date of the AD.
    Another commenter states that it performs the repetitive 
replacement of the O-rings and retaining rings during its D-check, and 
asks that all operators be allowed to perform the replacement at that 
time. The commenter also provides some statistics on cases of fuel 
leakage found and the corrective actions taken; and noted that there 
were more fuel leaks that occurred after maintenance of the fuel line 
coupling O-rings if specially trained mechanics did not do the 
maintenance, due to the necessity of using delicate installation 
procedures that are specific to that type of couplings.
    We do not agree with the requests to extend the compliance time. 
The chronological age of the O-rings combined with flight hours 
produces the deterioration and fuel leaks. With regard to extending the 
compliance time to allow the replacement to be accomplished at a D-
check or every 5 years, we have already considered factors such as 
operators' maintenance schedules in setting a compliance time for the 
required replacement and determined that 21,000 flight hours or 5 
years, whichever is earlier (unless a coupling is disassembled), is an 
appropriate compliance time in which the replacement may be 
accomplished during scheduled airplane maintenance for the majority of 
affected operators. Since maintenance schedules vary from operator to 
operator, it would not be possible to guarantee that all affected 
airplanes could be modified during scheduled maintenance. In any event, 
we find that the specified compliance time represents the maximum time 
wherein the affected airplanes may continue to operate without 
compromising safety. No change to the final rule is necessary in this 
regard.

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.

Changes to 14 CFR Part 39/Effect on the Proposed AD

    On July 10, 2002, the FAA issued a new version of 14 CFR part 39 
(67 FR 47997, July 22, 2002), which governs the FAA's airworthiness 
directives system. This regulation now includes material that relates 
to altered products, special flight permits, and AMOCs. Because we have 
now included this material in part 39, only the office authorized to 
approve AMOCs is identified in each individual AD. However, for clarity 
and consistency in this final rule, we have retained the language of 
the NPRM regarding that material.

Change to Labor Rate Estimate

    We have reviewed the figures we have used over the past several 
years to calculate AD costs to operators. To account for various 
inflationary costs in the airline industry, we find it necessary to 
increase the labor rate used in these calculations from $60 per work 
hour to $65 per work hour. The cost impact information, below, reflects 
this increase in the specified hourly labor rate.

Cost Impact

    The following table provides the cost estimates to accomplish the 
required actions:

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                                                                                            Number of
    Boeing service information for required        Work      Hourly     Parts       Per-       U.S.       U.S.
                    actions                     hours per    labor     cost per   airplane  airplanes    fleet
                                                 airplane     rate     airplane     cost     affected     cost
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Service Bulletin 747-36-2111..................         10        $65         $0       $650         32    $20,800
Service Bulletin 747-28-2230..................          4         65          0        260         32      8,320
Service Letter 747-SL-28-052-B................          4         65          0        260         32      8,320
Service Bulletin 747-36-2118..................         10         65      1,269      1,919         32     61,408
Service Bulletin 747-54-2137..................         48         65      3,047      6,167         30    185,010
Service Bulletin 747-54-2122..................         56         65      2,590      6,230         30    186,900
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    The cost impact figures discussed 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

[[Page 47215]]

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

0
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

0
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]

0
2. Section 39.13 is amended by adding the following new airworthiness 
directive:

2003-16-06 Boeing: Amendment 39-13259. Docket 2001-NM-232-AD.

    Applicability: Model 747 series airplanes equipped with General 
Electric CF6-45 or CF6-50 series engines, 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 (i) 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 leaking fuel line couplings, chafed fuel lines, 
restricted or clogged strut drain lines, fluids or vapors migrating 
to ignition sources, and flashback of external flame into the strut, 
which could result in uncontained engine strut fire, accomplish the 
following:

Inspection for Chafing and Clearance

    Note 2: Paragraph (a) of this AD refers to certain portions of 
Boeing Service Bulletin 747-36-2111, dated February 20, 1992, for 
information regarding inspection and measurement actions. Further, 
paragraph (a) of this AD requires replacement of the fuel tube as 
corrective action for certain repair conditions; that action is not 
included in the service bulletin. Where this AD and Service Bulletin 
747-36-2111 differ, the AD prevails.
    (a) Within 1,000 flight hours after the effective date of this 
AD, perform a detailed inspection to detect chafing of the fuel line 
and measure the clearance between the fuel line and the insulation 
blanket on the pneumatic duct, in accordance with the Accomplishment 
Instructions of Boeing Service Bulletin 747-36-2111, dated February 
20, 1992. Before further flight, accomplish all applicable 
corrective actions (including reworking the fuel line, remeasuring 
the clearance between the fuel line and the insulation blanket, 
adjusting the pneumatic duct and fuel line positions, adjusting the 
insulation blanket installation, and inspecting and cleaning the 
strut and strut drain ports/screens); and, if applicable, repeat the 
fuel line inspection at the applicable time in the Accomplishment 
Instructions of the service bulletin. Do the corrective and follow-
on actions in accordance with Service Bulletin 747-36-2111. If, 
after corrective actions have been performed, a clearance of at 
least 0.40 inch on the number 4 strut cannot be achieved: Before 
further flight, replace the fuel tube with a new part in accordance 
with Boeing Service Bulletin 747-28-2162, dated July 30, 1992.


    Note 3: For the purposes of this AD, a detailed inspection is 
defined as: ``An intensive visual examination of a specific 
structural area, system, installation, or assembly to detect damage, 
failure, or irregularity. Available lighting is normally 
supplemented with a direct source of good lighting at intensity 
deemed appropriate by the inspector. Inspection aids such as mirror, 
magnifying lenses, etc., may be used. Surface cleaning and elaborate 
access procedures may be required.''

Fuel Leak Check and Outboard Strut Drain Inspection

    (b) Within 12 months after the effective date of this AD, 
perform a fuel pressure leak check of the fuel line in the outboard 
strut area, and perform an outboard strut drain test for the aft 
strut drain tubes to detect blockage; in accordance with the 
Accomplishment Instructions of Boeing Special Attention Service 
Bulletin 747-28-2230, dated September 30, 1999. If any discrepancy 
is found, before further flight, perform applicable corrective 
actions (including performing the fuel pressure check procedure, 
clearing the strut drain tubes, and repairing seal leaks) in 
accordance with the service bulletin.

Replacement of O-Rings and Retaining Rings

    (c) At the earliest of the times specified by paragraphs (c)(1), 
(c)(2), and (c)(3) of this AD, replace the fuel line coupling O-
rings and retaining rings in the outboard strut positions with new 
Nitrile O-rings, part number MS29513-330, in accordance with Boeing 
Service Letter 747-SL-28-052-B, dated August 30, 1998. Replace the 
rings thereafter at the time specified by paragraph (d) of this AD.
    (1) Within 21,000 flight hours after the effective date of this 
AD.
    (2) Within 5 years after the effective date of this AD.
    (3) Before further flight after a coupling has been disassembled 
for any reason.

Repetitive Ring Replacement

    (d) Replace the rings as required by paragraph (c) of this AD at 
intervals not to exceed the earliest of the times specified by 
paragraphs (d)(1), (d)(2), and (d)(3) of this AD.
    (1) Every 21,000 flight hours.
    (2) Every 5 years.
    (3) Before further flight after a coupling has been disassembled 
for any reason.

Replacement of Pneumatic Duct Boot

    (e) At the earlier of the times specified in paragraphs (e)(1) 
and (e)(2) of this AD: Replace the fiberglass fabric pneumatic duct 
boot with a new NOMEX fabric part, in accordance with Boeing Service 
Bulletin 747-36-2118, dated January 28, 1993.
    (1) Within 12 months after the effective date of this AD; or
    (2) Before further flight following detection of any torn boot; 
or within 5 days following detection of any torn boot, provided 
there are no leaks, liquid fuel, or vapors in the affected strut 
compartment.

Installation of Flame Arrestor

    (f) For airplanes identified in Boeing Service Bulletin 747-54-
2137, dated February 6, 1992: Within 24 months after the effective 
date of this AD, install a flame arrestor in each aft condensate 
drain hole of the outboard engine struts, in accordance with the 
Accomplishment Instructions of the service bulletin.

Installation of Drain Screen

    (g) For Group 2 and Group 4 airplanes listed in Boeing Service 
Bulletin 747-54-2122, Revision 4, dated August 29, 1991, as revised 
by Notice of Status Change 747-54-2122 NSC 2, dated May 14, 1992; 
and Information Notice 747-54-2122 IN 03, dated August 19, 1999: 
Within 24 months after the effective date of this AD, install a 
drain line entry screen at each drain tube entry at the outboard 
strut positions, in accordance with the Accomplishment Instructions 
of the service bulletin. Where the service bulletin specifies that 
certain actions may be accomplished in accordance with an operator's 
``equivalent procedure': Those actions must be accomplished in 
accordance with the applicable Boeing 747 Airplane Maintenance 
Manual subject specified in the service bulletin.
    (h) Installation of drain screens before the effective date of 
this AD is also acceptable for compliance with the requirements of 
paragraph (g) of this AD if accomplished in accordance with Boeing 
Service Bulletin 747-54-2122, Revision 1, dated December 14, 1989; 
Revision 2, dated May 3, 1990; or Revision 3, dated October 4, 1990.

Alternative Methods of Compliance

    (i) 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

[[Page 47216]]

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 4: 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

    (j) Special flight permits may be issued in accordance with 
sections 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

    (k) Unless otherwise specified in this AD, the actions shall be 
done in accordance with Boeing Service Bulletin 747-36-2111, dated 
February 20, 1992; Boeing Service Bulletin 747-28-2162, dated July 
30, 1992; Boeing Special Attention Service Bulletin 2 747-28-2230, 
dated September 30, 1999; Boeing Service Letter 747-SL-28-052-B, 
dated August 30, 1998; Boeing Service Bulletin 747-36-2118, dated 
January 28, 1993; Boeing Service Bulletin 747-54-2137, dated 
February 6, 1992; and Boeing Service Bulletin 747-54-2122, Revision 
4, dated August 29, 1991, as revised by Notice of Status Change 747-
54-2122 NSC 2, dated May 14, 1992, and Information Notice 747-54-
2122 IN 03, dated August 19, 1999; 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

    (l) This amendment becomes effective on September 12, 2003.

    Issued in Renton, Washington, on July 31, 2003.
Ali Bahrami,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 03-19981 Filed 8-7-03; 8:45 am]
BILLING CODE 4910-13-P