[Federal Register Volume 71, Number 77 (Friday, April 21, 2006)]
[Rules and Regulations]
[Pages 20528-20530]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 06-3796]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2005-23441; Directorate Identifier 2005-NM-199-AD; 
Amendment 39-14571; AD 2006-09-01]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747-100, 747-100B, 747-
100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747SR, and 747SP 
Series Airplanes

AGENCY: Federal Aviation Administration (FAA), Department of 
Transportation (DOT).

ACTION: Final rule.

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SUMMARY: The FAA is superseding an existing airworthiness directive 
(AD), which applies to certain Boeing Model 747-100, 747-100B, 747-100B 
SUD, 747-200B, 747-200C, 747-200F, 747-300, 747SR, and 747SP series 
airplanes. That AD currently requires repetitive detailed and 
ultrasonic inspections of the thrust links of the rear engine mounts 
for any crack or fracture and corrective actions if necessary. This new 
AD requires repetitive replacement of the thrust links with new or 
overhauled thrust links, which ends the repetitive detailed and 
ultrasonic inspections. This AD results from the finding of fractured 
and cracked forward lugs of the rear engine mount thrust link on the 
number one strut on two airplanes. We are issuing this AD to prevent 
cracked or fractured thrust links that could lead to the loss of the 
load path for the rear engine mount bulkhead and damage to other 
primary engine mount structure, which could result in the in-flight 
separation of the engine from the airplane and consequent loss of 
control of the airplane.

DATES: This AD becomes effective May 26, 2006.
    On September 30, 2005 (70 FR 54474, September 15, 2005), the 
Director of the Federal Register approved the incorporation by 
reference of Boeing Alert Service Bulletin 747-71A2309, dated August 
18, 2005.

ADDRESSES: You may examine the AD docket on the Internet at http://dms.dot.gov or in person at the Docket Management Facility, U.S. 
Department of Transportation, 400 Seventh Street, SW., Nassif Building, 
room PL-401, Washington, DC.
    Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, 
Washington 98124-2207, for service information identified in this AD.

FOR FURTHER INFORMATION CONTACT: Ivan Li, Aerospace Engineer, Airframe 
Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind 
Avenue, SW., Renton, Washington 98055-4056; telephone (425) 917-6437; 
fax (425) 917-6590.

SUPPLEMENTARY INFORMATION:

Examining the Docket

    You may examine the airworthiness directive (AD) docket on the 
Internet at http://dms.dot.gov or in person at the Docket Management 
Facility office between 9 a.m. and 5 p.m., Monday through Friday, 
except Federal holidays. The Docket Management Facility office 
(telephone (800) 647-5227) is located on the plaza level of the Nassif 
Building at the street address stated in the ADDRESSES section.

Discussion

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 to include an AD that supersedes AD 2005-19-06, amendment 
39-14271 (70 FR 54474, September 15, 2005). The existing AD applies to 
certain Boeing Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-
200C, 747-200F, 747-300, 747SR, and 747SP series airplanes. That NPRM 
was published in the Federal Register on January 11, 2006 (71 FR 1718). 
That NPRM proposed to continue to require repetitive detailed and 
ultrasonic inspections of the thrust links of the rear engine mounts 
for any crack or fracture and corrective actions if necessary. That 
NPRM also proposed to require repetitive replacement of the thrust 
links with new or overhauled thrust links, which ends the repetitive 
detailed and ultrasonic inspections.

Comments

    We provided the public the opportunity to participate in the 
development of this AD. We have considered the comments that have been 
received on the NPRM.

Support for the NPRM

    Boeing and Northwest Airlines (NWA) support the NPRM.

Request for Clarification

    NWA states that, as a result of the inspections required by AD 
2005-19-06, some thrust links may have already been replaced with new 
or overhauled thrust links (prior to the initial compliance time 
specified in Table 1 of the NPRM). According to NWA's interpretation of 
paragraph (e) of the NPRM, replacements done previously in accordance 
with AD 2005-19-06 comply with the initial replacement specified in the 
NPRM. We infer that the commenter would like us to clarify whether this 
interpretation is correct.
    We agree that, under paragraph (e) of this AD, the actions required 
by this AD must be accomplished within the specified compliance times, 
unless the actions have been previously accomplished. Therefore, 
replacement of a cracked or fractured thrust link in accordance with 
paragraph (h) of AD 2005-19-06 constitutes compliance with the initial 
replacement required by paragraph (k) of this AD, for that thrust link 
only. No change to this AD is necessary.

Conclusion

    We have carefully reviewed the available data, including the 
comments that have been submitted, and determined that air safety and 
the public interest require adopting the AD as proposed.

Costs of Compliance

    There are about 274 airplanes of the affected design in the 
worldwide fleet. The following table provides the estimated costs, at 
an average labor rate of $65 per hour, for U.S. operators to comply 
with this AD.

[[Page 20529]]



                                                                     Estimated Costs
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                                                                                                                      Number of
                                                                                                                        U.S.-
               Action                            Work hours                    Parts            Cost per airplane     registered        Fleet cost
                                                                                                                      airplanes
--------------------------------------------------------------------------------------------------------------------------------------------------------
Inspection (required by AD 2005-19-   8 (2 per engine)...............  None................  $520, per inspection            100  $52,000, per
 06).                                                                                         cycle.                               inspection cycle.
Replacement (new action)............  4 (1 per engine)...............  $41,424.............  $41,684, per                    100  $4,168,400, per
                                                                                              replacement cycle.                   replacement cycle.
--------------------------------------------------------------------------------------------------------------------------------------------------------

Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue rules on aviation safety. 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.
    We are issuing this rulemaking under the authority described in 
subtitle VII, part A, subpart III, section 44701, ``General 
requirements.'' Under that section, Congress charges the FAA with 
promoting safe flight of civil aircraft in air commerce by prescribing 
regulations for practices, methods, and procedures the Administrator 
finds necessary for safety in air commerce. This regulation is within 
the scope of that authority because it addresses an unsafe condition 
that is likely to exist or develop on products identified in this 
rulemaking action.

Regulatory Findings

    We have determined that this AD will not have federalism 
implications under Executive Order 13132. This AD 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.
    For the reasons discussed above, I certify that this AD:
    (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.
    We prepared a regulatory evaluation of the estimated costs to 
comply with this AD and placed it in the AD docket. See the ADDRESSES 
section for a location to examine the regulatory evaluation.

List of Subjects in 14 CFR Part 39

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

Adoption of the Amendment

0
Accordingly, under the authority delegated to me by the Administrator, 
the FAA amends 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. The Federal Aviation Administration (FAA) amends Sec.  39.13 by 
removing amendment 39-14271 (70 FR 54474, September 15, 2005) and by 
adding the following new airworthiness directive (AD):

2006-09-01 Boeing: Amendment 39-14571. Docket No. FAA-2005-23441; 
Directorate Identifier 2005-NM-199-AD.

Effective Date

    (a) This AD becomes effective May 26, 2006.

Affected ADs

    (b) This AD supersedes AD 2005-19-06.

Applicability

    (c) This AD applies to Boeing Model 747-100, 747-100B, 747-100B 
SUD, 747-200B, 747-200C, 747-200F, 747-300, 747SR, and 747SP series 
airplanes, certificated in any category; equipped with Pratt & 
Whitney JT9D-3 and -7 series engines, except JT9D-70 engines; as 
identified in Boeing Alert Service Bulletin 747-71A2309, dated 
August 18, 2005.

Unsafe Condition

    (d) This AD results from the finding of fractured and cracked 
forward lugs of the rear engine mount thrust link on the number one 
strut on two airplanes. We are issuing this AD to prevent cracked or 
fractured thrust links that could lead to the loss of the load path 
for the rear engine mount bulkhead and damage to other primary 
engine mount structure, which could result in the in-flight 
separation of the engine from the airplane and consequent loss of 
control of the airplane.

Compliance

    (e) You are responsible for having the actions required by this 
AD performed within the compliance times specified, unless the 
actions have already been done.

Restatement of Requirements of AD 2005-19-06

Service Bulletin References

    (f) The term ``service bulletin,'' as used in this AD, means the 
Accomplishment Instructions of Boeing Alert Service Bulletin 747-
71A2309, dated August 18, 2005.

Repetitive Inspections of Thrust Links

    (g) Within 90 days after September 30, 2005 (the effective date 
of AD 2005-19-06), do a detailed inspection and ultrasonic 
inspection of thrust link lugs having part number (P/N) 65B90360-1 
or -4 of the rear engine mount of struts 1, 2, 3, and 4 for any 
crack or fracture, in accordance with Part 1 of the service 
bulletin. If the thrust link is not found cracked or fractured: 
Repeat the inspections thereafter at intervals not to exceed 1,200 
flight cycles or 18 months, whichever is first, until the repetitive 
replacement or overhaul of the thrust link required by paragraph (k) 
of this AD is accomplished. Accomplishing the repetitive replacement 
or overhaul of a thrust link as specified in paragraph (h) or (k) of 
this AD terminates the repetitive inspections for that thrust link 
only.

Corrective Actions

    (h) If a cracked thrust link is found during any inspection 
required by paragraph (g) of this AD or during any replacement or 
overhaul done in accordance with the service bulletin: Before 
further flight, do the actions specified in paragraph (h)(1) of this 
AD. If a fractured thrust link is found during any inspection 
required by paragraph (g) of this AD or during any replacement or 
overhaul done in accordance with the service bulletin: Before 
further flight, do the actions specified in paragraphs (h)(1) and 
(h)(2) of this AD.
    (1) Replace the thrust link with a new or overhauled thrust link 
in accordance with Part 2 of the service bulletin; except as 
provided by paragraph (i) of this AD. Repeat the replacement at the 
applicable compliance time specified in paragraph (h)(1)(i) or 
(h)(1)(ii) of this AD.
    (i) For replacement with a thrust link assembly having P/N 
65B90360-1 or -4: Thereafter at intervals not to exceed 6,000 flight 
cycles.
    (ii) For replacement with a thrust link assembly having P/N 
65B90360-7: Thereafter at intervals not to exceed 12,000 flight 
cycles.
    (2) Do the corrective actions in accordance with Parts 3, 4, and 
5 of the service bulletin; except as provided by paragraph (i) of 
this AD.

[[Page 20530]]

Exception to Service Bulletin

    (i) Where the service bulletin specifies to contact Boeing for 
appropriate action, do the corrective action using a method approved 
in accordance with paragraph (l) of this AD.

Credit for Certain Corrective Actions

    (j) Reworking the lugs on the bulkhead fitting of the rear 
engine mount as specified in paragraphs (b)(2), (e), and (f) of AD 
2001-15-15, amendment 39-12349, is acceptable for compliance with 
accomplishing the corrective action specified in ``Part 3--Rear 
Engine Mount Bulkhead Inspection and Lug Overhaul and Upper Fitting 
Overhaul and Bolt Replacement'' of the service bulletin.

New Requirements of This AD

Terminating Action--Repetitive Replacement or Overhaul of All 
Thrust Links

    (k) At the applicable compliance times specified in Table 1 of 
this AD: Repetitively replace the thrust link of the rear engine 
mount of struts 1, 2, 3, and 4 with a new or overhauled thrust link, 
in accordance with Part 2 of the service bulletin; except as 
provided by paragraph (i) of this AD. During any replacement 
required by this paragraph, an existing thrust link may be replaced 
with a new or overhauled thrust link having P/N 65B90360-1, -4 or -
7, provided that the applicable repetitive interval specified in 
Table 1 of this AD is complied with. If a fractured thrust link is 
found during any replacement or overhaul done in accordance with 
this paragraph: Before further flight, do the corrective actions 
specified in paragraph (h)(2) of this AD. Repetitive replacement of 
all thrust links having P/N 65B90360-1 or -4 terminates the 
repetitive inspections required by paragraph (g) of this AD. 
Accomplishing the repetitive replacement or overhaul of a thrust 
link required by paragraph (h) of this AD constitutes compliance 
with the requirements of this paragraph for that thrust link only.

                       Table 1.--Compliance Times
------------------------------------------------------------------------
                                        Initial           Repetitive
      For thrust link P/N--          replacement--        interval--
------------------------------------------------------------------------
65B90360-1 or -4................  Within 36 months    Thereafter at
                                   after the           intervals not to
                                   effective date of   exceed 6,000
                                   this AD.            flight cycles.
65B90360-7......................  Within 12,000       Thereafter at
                                   flight cycles       intervals not to
                                   after the new       exceed 12,000
                                   thrust link has     flight cycles.
                                   been installed.
------------------------------------------------------------------------

Alternative Methods of Compliance (AMOCs)

    (l)(1) The Manager, Seattle Aircraft Certification Office (ACO), 
FAA, has the authority to approve AMOCs for this AD, if requested in 
accordance with the procedures found in 14 CFR 39.19.
    (2) Before using any AMOC approved in accordance with Sec.  
39.19 on any airplane to which the AMOC applies, notify the 
appropriate principal inspector in the FAA Flight Standards 
Certificate Holding District Office.
    (3) An AMOC that provides an acceptable level of safety may be 
used for any repair required by this AD, if it is approved by an 
Authorized Representative for the Boeing Commercial Airplanes 
Delegation Option Authorization Organization who has been authorized 
by the Manager, Seattle ACO, to make those findings. For a repair 
method to be approved, the repair must meet the certification basis 
of the airplane, and the approval must specifically refer to this 
AD.
    (4) The actions identified in paragraphs (g) and (k) of this AD 
are approved as an AMOC to paragraphs (c) and (d) of AD 2004-07-22, 
amendment 39-13566, for the inspections of structural significant 
item S-2, for the thrust links only, of Boeing Supplemental 
Structural Inspection Document D6-35022, Revision G, dated December 
2000. All provisions of AD 2004-07-22 that are not specifically 
referenced in this paragraph, including the initial inspection 
threshold required by paragraph (d) of AD 2004-07-22, remain fully 
applicable and must be complied with.
    (5) AMOCs approved previously in accordance with AD 2005-19-06, 
amendment 39-14271, are approved as AMOCs for the corresponding 
provisions of this AD.

Material Incorporated by Reference

    (m) You must use Boeing Alert Service Bulletin 747-71A2309, 
dated August 18, 2005, to perform the actions that are required by 
this AD, unless the AD specifies otherwise. On September 30, 2005 
(70 FR 54474, September 15, 2005), the Director of the Federal 
Register approved the incorporation by reference of Boeing Alert 
Service Bulletin 747-71A2309, dated August 18, 2005. Contact Boeing 
Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207, 
for a copy of this service information. You may review copies at the 
Docket Management Facility, U.S. Department of Transportation, 400 
Seventh Street, SW., room PL-401, Nassif Building, Washington, DC; 
on the Internet at http://dms.dot.gov; or at the National Archives 
and Records Administration (NARA). For information on the 
availability of this material at the NARA, call (202) 741-6030, or 
go to http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

    Issued in Renton, Washington, on April 13, 2006.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 06-3796 Filed 4-20-06; 8:45 am]
BILLING CODE 4910-13-P