[Federal Register Volume 71, Number 225 (Wednesday, November 22, 2006)]
[Rules and Regulations]
[Pages 67445-67447]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E6-19534]


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

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2006-24877; Directorate Identifier 2005-NM-253-AD; 
Amendment 39-14831; AD 2006-24-02]
RIN 2120-AA64


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

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

ACTION: Final rule.

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

SUMMARY: The FAA is superseding an existing airworthiness directive 
(AD), which applies to certain Boeing Model 747 series airplanes. That 
AD currently requires repetitive inspections to detect cracks at 
certain stringer fastener locations; and repair, if necessary. For 
certain airplanes, that AD requires a modification in certain areas 
where reports indicate that cracking was prevalent. This modification 
terminates the repetitive inspections only for those areas, and is also 
an option for other airplanes affected by the existing AD. This new AD 
requires an additional inspection of areas that may have Alodine-coated 
rivets installed, and repair if necessary. This AD results from a 
report of cracking discovered in a skin lap joint that was previously 
inspected using the eddy current method. We are issuing this AD to 
prevent rapid decompression of the airplane due to disbonding and 
subsequent cracking of the skin panels.

DATES: This AD becomes effective December 27, 2006.
    The Director of the Federal Register approved the incorporation by 
reference of certain publications listed in the AD as of December 27, 
2006.

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 98057-3356; 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 90-26-10, amendment 39-
6836 (55 FR 51401, December 14, 1990). The existing AD applies to 
certain Boeing Model 747 series airplanes. That NPRM was published in 
the Federal Register on May 25, 2006 (71 FR 30074). That NPRM proposed 
to continue to require repetitive inspections to detect cracks at 
certain stringer fastener locations, and repair if necessary. For 
certain airplanes, that NPRM proposed to continue to require 
modification in certain areas where reports indicate that cracking was 
prevalent. This modification terminates the repetitive inspections only 
for those areas, and is also an option for other airplanes affected by 
the existing AD. That NPRM also proposed to require an additional 
inspection of areas that may have Alodine-coated rivets installed, and 
repair if necessary.

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 supports the NPRM.

Request To Recognize Overlapping Inspections

    The Air Transport Association, on behalf of one of its members, 
Northwest Airlines, requests that we recognize that a service bulletin 
currently in development could result in overlapping inspections and 
cause duplication of efforts. Northwest Airlines states that it has 
been advised by Boeing that the service bulletin in development will 
recommend external detailed inspections and/or external surface high 
frequency eddy current inspections in a good portion of the region 
affected by the NPRM. This new service bulletin resulted from a recent 
report of skin cracking in section 41.
    We partially agree with the commenters. We agree that it is 
important to avoid duplication of effort. However, because the service 
bulletin that the commenters mention has not been issued, we have not 
issued an NPRM for the subject of that service bulletin. When the 
service bulletin is issued, we will review it and any forthcoming 
proposed rule in an effort to prevent duplication of tasks. We consider 
that to delay this AD action would be inappropriate, since we have 
determined that an unsafe condition exists and that replacement of 
certain parts must be accomplished to ensure continued safety. We have 
not changed the AD in this regard.

Explanation of Editorial Changes

    We have clarified the Summary section of this AD to state that this 
new AD requires ``an additional inspection'' rather than a one-time 
inspection at a reduced threshold. The new inspection required by this 
AD is ``additional'' and, therefore, we are not reducing a threshold in 
the previous AD.
    We have also removed the words, ``at intervals not to exceed 150 
flight cycles'' from paragraph (k)(1)(i) of this AD because it 
duplicates information already in paragraph (k)(1) of this AD, and may 
cause confusion.

Conclusion

    We have carefully reviewed the available data, including the 
comments received, and determined that air safety and the public 
interest require adopting the AD with the changes described previously. 
We have determined that these changes will neither increase the 
economic burden on any operator nor increase the scope of the AD.

Costs of Compliance

    The following table provides the estimated costs for U.S. operators 
to comply with this AD. There are about 132 airplanes of the affected 
design in the worldwide fleet. This AD affects about 59 airplanes of 
U.S. registry. The average labor rate is $80 per work hour.

[[Page 67446]]



                                                                     Estimated Costs
--------------------------------------------------------------------------------------------------------------------------------------------------------
               Action                   Work hours              Parts              Cost per airplane                       Fleet cost
--------------------------------------------------------------------------------------------------------------------------------------------------------
Inspection (required by AD 90-26-10)              48  None....................  $3,840, per inspection  $226,560, per inspection cycle.
                                                                                 cycle.
Modification (required by AD 90-26-              620  $69,246.................  $118,846..............  $7,011,914.
 10).
Inspection (new action).............              48  None....................  $3,840, per inspection  $226,560, per inspection cycle.
                                                                                 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 39-6836 (55 FR 51401, December 14, 1990) and by 
adding the following new airworthiness directive (AD):

2006-24-02 Boeing: Amendment 39-14831. Docket No. FAA-2006-24877; 
Directorate Identifier 2005-NM-253-AD.

Effective Date

    (a) This AD becomes effective December 27, 2006.

Affected ADs

    (b) This AD supersedes AD 90-26-10.

Applicability

    (c) This AD applies to Boeing Model 747-100, 747-100B, 747-200B, 
747-200C, 747-200F, 747SR, and 747SP series airplanes, certificated 
in any category; line numbers 001 through 430 inclusive.

Unsafe Condition

    (d) This AD results from a report of cracking discovered in a 
skin lap joint that was previously inspected using the eddy current 
method. We are issuing this AD to prevent rapid decompression of the 
airplane due to disbonding and subsequent cracking of the skin 
panels.

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 Certain Requirements of AD 90-26-10

Inspections

    (f) Prior to the accumulation of 12,000 flight cycles or within 
the next 1,000 flight cycles after January 22, 1991 (the effective 
date of AD 90-26-10), whichever occurs later, unless previously 
accomplished within the last 1,000 flight cycles, conduct an 
external detailed and external high frequency eddy current (HFEC) 
inspection for cracks of the fuselage skin from body station (BS) 
220 to BS 520, left- and right-hand sides of the airplane between 
stringers (S)-6 and S-14, excluding the skin lap joints, in 
accordance with the Accomplishment Instructions of Boeing Alert 
Service Bulletin 747-53A2321, dated October 31, 1989; or Revision 7, 
dated October 27, 2005. After the effective date of this AD, only 
Revision 7 may be used. Doing the inspections in this paragraph in 
accordance with Revision 7 of the service bulletin eliminates the 
need for doing the actions in paragraph (k) of this AD. Repeat the 
inspections thereafter at intervals not to exceed 2,000 flight 
cycles until the terminating modification in paragraph (g) of this 
AD is done, except as provided by paragraph (h) of this AD.

    Note 1: For the purposes of this AD, a detailed inspection is: 
``An intensive examination of a specific item, installation, or 
assembly to detect damage, failure, or irregularity. Available 
lighting is normally supplemented with a direct source of good 
lighting at an intensity deemed appropriate. Inspection aids such as 
mirror, magnifying lenses, etc., may be necessary. Surface cleaning 
and elaborate procedures may be required.''

Terminating Modification

    (g) For airplanes line numbers 001 through 200 inclusive, prior 
to the accumulation of 20,000 total flight cycles, or within 48 
months after the January 22, 1991, whichever occurs later: Perform 
the terminating modification of the skin panel from BS 340 to BS 
520, S-6 to S-14, in accordance with the Accomplishment Instructions 
of Boeing Alert Service Bulletin 747-53A2321, dated October 31, 
1989; or Revision 7, dated October 27, 2005. After the effective 
date of this AD, only Revision 7 may be used. The modification 
consists of replacing the skin panel with a new skin panel which was 
manufactured utilizing the improved hot phosphoric acid anodize 
bonding process.
    (h) Replacement of the skin panel required by paragraph (g) of 
this AD constitutes terminating action for the inspections from BS 
340 to BS 520 required by paragraphs (f) and (k) of this AD. The 
inspections from BS 220 to BS 340 required by paragraph (f) of this 
AD are to be continued.

Adjustments for Cabin Differential Pressure

    (i) Before the effective date of this AD: Flight cycles 
conducted at 2.0 pounds per square inch (psi) or less cabin 
differential pressure need not be counted for the purpose of this 
airworthiness directive.
    (j) Before the effective date of this AD: For Model 747SR 
airplanes only, the threshold

[[Page 67447]]

and repetitive inspection intervals specified herein may be 
multiplied by the 1.2 adjustment factor based on continued mixed 
operation at lower cabin pressure differentials.

New Requirements of This AD

Additional Inspection of Skins With Alodine-Coated Rivets

    (k) For airplanes identified in Figure 9 of the Accomplishment 
Instructions of Boeing Alert Service Bulletin 747-53A2321, Revision 
7, dated October 27, 2005, as requiring additional inspection: 
Within 150 flight cycles after the effective date of this AD, do the 
inspection in paragraph (k)(1) or (k)(2) of this AD in accordance 
with the Accomplishment Instructions of the service bulletin.
    (1) Do an external detailed inspection for cracking of Area 1, 
and repeat the inspection thereafter at intervals not to exceed 150 
flight cycles until one of the actions in paragraph (k)(1)(i), 
(k)(1)(ii), or (k)(1)(iii) is accomplished. Repeat the inspection of 
Area 1 thereafter in accordance with the requirements of paragraph 
(f) of this AD.
    (i) The inspection in accordance with paragraph (k)(1) of this 
AD has been done seven times. If this option is used: Within 150 
flight cycles after the seventh inspection, do the inspection 
required by paragraph (k)(2) of this AD.
    (ii) The inspection in accordance with paragraph (k)(2) has been 
accomplished.
    (iii) The inspections in accordance with paragraph (f) of this 
AD has been accomplished once in accordance with Revision 7 of the 
service bulletin.
    (2) Do an external HFEC inspection for cracking of Area 1 in 
accordance with the Accomplishment Instructions of Boeing Alert 
Service Bulletin 747-53A2321, Revision 7, dated October 27, 2005. 
Repeat the inspection of Area 1 thereafter in accordance with the 
requirements of paragraph (f) of this AD.

Repair

    (l) If any crack is found during any inspection required by this 
AD: Before further flight, repair in accordance with the 
Accomplishment Instructions of Boeing Alert Service Bulletin 747-
53A2321, dated October 31, 1989; or Revision 7, dated October 27, 
2005. After the effective date of this AD, only Revision 7 of the 
service bulletin may be used. Where Revision 7 of the service 
bulletin specifies to contact Boeing for repair instructions: Before 
further flight, repair using a method approved in accordance with 
the procedures specified in paragraph (n) of this AD.

Adjustments to Compliance Time: Cabin Differential Pressure

    (m) For the purposes of calculating the compliance threshold and 
repetitive interval for actions required by paragraphs (f), (g), and 
(k) of this AD, on or after the effective date of this AD: All 
flight cycles, including the number of flight cycles in which cabin 
differential pressure is at 2.0 psi or less, must be counted when 
determining the number of flight cycles that have occurred on the 
airplane, and a 1.2 adjustment factor may not be used. However, for 
airplanes on which the repetitive interval for the actions required 
by paragraphs (f) and (k) of this AD have been calculated in 
accordance with paragraph (i) or (j) of this AD by excluding the 
number of flight cycles in which cabin differential pressure is at 
2.0 pounds psi or less, or by using a 1.2 adjustment factor: 
Continue to adjust the repetitive interval in accordance with 
paragraph (i) or (j) of this AD until the next inspections required 
by paragraph (f) or (k) of this AD are accomplished. Thereafter, no 
adjustment to compliance times based on paragraph (i) or (j) of this 
AD is allowed.

Alternative Methods of Compliance (AMOCs)

    (n)(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.
    (4) AMOCs approved previously in accordance with AD 90-26-10 are 
acceptable for compliance with the requirements of this AD, provided 
that any alternative terminating action was not based upon 
inspection results using sliding probe low-frequency eddy current 
(LFEC), sliding probe HFEC, or mid-frequency eddy current (MFEC) 
inspection method; and provided that any alternative method future 
inspections did not incorporate sliding probe LFEC or MFEC 
inspection method.

Material Incorporated by Reference

    (o) You must use Boeing Alert Service Bulletin 747-53A2321, 
dated October 31, 1989; and Boeing Alert Service Bulletin 747-
53A2321, Revision 7, dated October 27, 2005; as applicable; to 
perform the actions that are required by this AD, unless the AD 
specifies otherwise. (Only the first page of Boeing Alert Service 
Bulletin 747-53A2321, dated October 31, 1989, contains the document 
issue date; no other page of this document contains this 
information.) The Director of the Federal Register approved the 
incorporation by reference of these documents in accordance with 5 
U.S.C. 552(a) and 1 CFR part 51. 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 November 8, 2006.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
 [FR Doc. E6-19534 Filed 11-21-06; 8:45 am]
BILLING CODE 4910-13-P