
[Federal Register Volume 76, Number 125 (Wednesday, June 29, 2011)]
[Proposed Rules]
[Pages 38074-38077]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-16370]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2011-0645; Directorate Identifier 2010-NM-009-AD]
RIN 2120-AA64


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

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

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to supersede an existing airworthiness 
directive (AD) that applies to certain Model 747 series airplanes. The 
existing AD currently requires repetitive inspections for cracks of the 
fuselage skin lap splice between body station (BS) 400 and BS 520 at 
stringers S-6L and S-6R, and repair if necessary. This proposed AD 
would shorten the interval for the repetitive inspections, require 
modification for certain airplanes, and require certain post-
modification inspections for other airplanes. This proposed AD results 
from reports of multiple adjacent cracks on an airplane, and a recent 
fleet-wide evaluation of widespread fatigue damage of skin lap joints, 
which indicated the need for revised procedures and reduced compliance 
times. We are proposing this AD to detect and correct cracking of the 
fuselage skin lap splice between BS 400 and BS 520 at stringers S-6L 
and S-6R. Such cracking could result in sudden loss of cabin 
pressurization and the inability of the fuselage to withstand fail-safe 
loads.

DATES: We must receive comments on this proposed AD by August 15, 2011.

ADDRESSES: You may send comments by any of the following methods:
     Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.
     Fax: 202-493-2251.
     Mail: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue, SE., Washington, DC 20590.
     Hand Delivery: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue, SE., Washington, DC 20590, between 9 a.m. and 5 p.m., 
Monday through Friday, except Federal holidays.
    For service information identified in this proposed AD, contact 
Boeing Commercial Airplanes, Attention: Data & Services Management, 
P.O. Box 3707, MC 2H-65, Seattle, Washington 98124-2207; telephone 206-
544-5000, extension 1; fax 206-766-5680; e-mail me.boecom@boeing.com; 
Internet https:[sol][sol]www.myboeingfleet.com. You may review copies 
of the referenced service information at the FAA, Transport Airplane 
Directorate, 1601 Lind Avenue, SW., Renton, Washington. For information 
on the availability of this material at the FAA, call 425-227-1221.

Examining the AD Docket

    You may examine the AD docket on the Internet at 
http:[sol][sol]www.regulations.gov; or in person at the Docket 
Management Facility between 9 a.m. and 5 p.m., Monday through Friday, 
except Federal holidays. The AD docket contains this proposed AD, the 
regulatory evaluation, any comments received, and other information. 
The street address for the Docket Office (telephone 800-647-5527) is in 
the

[[Page 38075]]

ADDRESSES section. Comments will be available in the AD docket shortly 
after receipt.

FOR FURTHER INFORMATION CONTACT: Bill Ashforth, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office 
(ACO), 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone 
425-917-6432; fax 425-917-6590; e-mail: bill.ashforth@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to send any written relevant data, views, or 
arguments about this proposed AD. Send your comments to an address 
listed under the ADDRESSES section. Include ``Docket No. FAA-2011-0645; 
Directorate Identifier 2010-NM-009-AD'' at the beginning of your 
comments. We specifically invite comments on the overall regulatory, 
economic, environmental, and energy aspects of this proposed AD. We 
will consider all comments received by the closing date and may amend 
this proposed AD because of those comments.
    We will post all comments we receive, without change, to 
http:[sol][sol]www.regulations.gov, including any personal information 
you provide. We will also post a report summarizing each substantive 
verbal contact we receive about this proposed AD.

Discussion

    On October 1, 1990, we issued AD 90-21-17, amendment 39-6768 (55 FR 
41510, October 12, 1990), for certain Model 747 series airplanes. That 
AD requires inspection of the fuselage skin lap splice between body 
station (BS) 400 and BS 520 at stringers (S) 6L or S-6R, and repair if 
necessary. That AD resulted from reports of multiple adjacent cracks on 
one airplane. We issued that AD to detect and correct such cracking, 
which could result in sudden loss of cabin pressurization and the 
inability of the airplane fuselage to withstand fail-safe loads.

Actions Since Existing AD Was Issued

    Since we issued AD 90-21-17, Boeing performed a fleet-wide 
evaluation of the Model 747 skin lap joints for widespread fatigue 
damage (WFD) and concluded that the existing repetitive interval of 
both the pre- and post-modification inspections needs to be reduced to 
preclude WFD. In addition, Boeing has determined that one of the 
existing modification options, which allow installation of protruding 
head fasteners without external reinforcement, does not provide 
adequate durability for WFD and must be prohibited, and all previously 
accomplished modifications that are inadequately reinforced (i.e., lap 
joints that have no external reinforcement or are only partially 
reinforced) must be reworked.

Relevant Service Information

    The appropriate source of service information for the required 
actions in AD 90-21-17 is Boeing Alert Service Bulletin 747-53A2303, 
dated June 2, 1988; and Revision 1, dated March 29, 1990. Boeing has 
since issued Boeing Service Bulletin 747-53A2303, Revision 2, dated 
October 1, 2009, which does the following:
     Shortens the interval for repetitive inspections from 
5,000 to 3,000 flight cycles, with a grace period of 1,000 flight 
cycles after the date on Revision 2 of the service bulletin.
     Adds installation of reinforcing doublers to the upper and 
lower skin of the lap splice for certain modified airplanes.
     Adds post-modification inspections which are internal and 
external high-frequency eddy current inspections for cracking in the 
area of the modification.

FAA's Determination and Requirements of the Proposed AD

    We have evaluated all pertinent information and identified an 
unsafe condition that is likely to develop on other airplanes of the 
same type design. For this reason, we are proposing this AD, which 
would supersede AD 90-21-17, retain its requirements, and require 
accomplishing the actions specified in Boeing Service Bulletin 747-
53A2303, Revision 2, dated October 1, 2009, described previously.

Changes to Existing AD

    We have made the following changes to the existing AD:
    1. Boeing Commercial Airplanes has received an Organization 
Designation Authorization (ODA). We have revised paragraph (p) in this 
proposed AD to add delegation of authority to Boeing Commercial 
Airplanes ODA to approve an alternative method of compliance for any 
repair required by this AD.
    2. Boeing Service Bulletin 747-53A2303, Revision 2, dated October 
1, 2009, specifies contacting the manufacturer for instructions on how 
to repair certain conditions, but this proposed AD would require 
repairing those conditions in one of the following ways:
     Using a method that we approve; or
     Using data that meet the certification basis of the 
airplane, and that have been approved by the Boeing Commercial 
Airplanes Organization Designation Authorization (ODA) whom we have 
authorized to make those findings.
    3. Paragraph A. of AD 90-21-17 specifies doing a ``close visual'' 
inspection. We have revised that paragraph (paragraph (g) in this NPRM) 
to also refer to a ``detailed inspection'' to correspond to the 
terminology used in Service Bulletin 747-53A2303, Revision 2, dated 
October 1, 2009. New Note 1 in this NPRM defines a detailed inspection.
    4. This proposed AD would retain the requirements of AD 90-21-17. 
Since that AD was issued, the AD format has been revised, and certain 
paragraphs have been rearranged. As a result, the corresponding 
paragraph identifiers have changed in this proposed AD, as listed in 
the following table:

                      Revised Paragraph Identifiers
------------------------------------------------------------------------
                                      Corresponding requirement in this
     Requirement in AD 90-21-17                  proposed AD
------------------------------------------------------------------------
            paragraph A                        paragraph (g)
            paragraph B                        paragraph (h)
             paragraph C                       paragraph (i)
            paragraph D                        paragraph (j)
            paragraph E                        paragraph (k)
------------------------------------------------------------------------

Costs of Compliance

    There are about 165 airplanes of the affected design in the 
worldwide fleet; of these, 64 are U.S.-registered airplanes. The 
following table provides the estimated costs for U.S. operators to 
comply with this proposed AD.

                                                 Estimated Costs
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                                                Average labor                       Cost per
           Action                Work hours     rate per hour       Parts           airplane        Fleet cost
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Inspection (required by AD    8..............             $85  $0.............  $680 per         $43,520 per
 90-21-17).                                                                      inspection       inspection
                                                                                 cycle.           cycle.

[[Page 38076]]

 
Modification (new proposed    Up to 370......              85  Between $954     Up to $33,514..  Up to
 action).                                                       and $2,064.                       $2,144,896.
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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 proposed AD would not have federalism 
implications under Executive Order 13132. This proposed AD 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.
    For the reasons discussed above, I certify that the 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. 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 proposed 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.

The Proposed Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA proposes to amend 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. The FAA amends Sec.  39.13 by removing amendment 39-6768 (55 FR 
41510, October 12, 1990) and adding the following new AD:

The Boeing Company: Docket No. FAA-2010-0645; Directorate Identifier 
2010-NM-009-AD.

Comments Due Date

    (a) The FAA must receive comments on this AD action by August 
15, 2011.

Affected ADs

    (b) This AD supersedes AD 90-21-17, Amendment 39-6768.

Applicability

    (c) This AD applies to The Boeing Company Model 747-100, 747-
100B, 747-200B, 747-200C, 747-200F, 747-300, 747SR, and 747SP series 
airplanes, certificated in any category, as identified in Boeing 
Service Bulletin 747-53A2303, Revision 2, dated October 1, 2009.

Subject

    (d) Air Transport Association (ATA) of America Code 53: 
Fuselage.

Unsafe Condition

    (e) This AD results from reports of multiple adjacent cracks on 
an airplane, and a recent fleet-wide evaluation of widespread 
fatigue damage of skin lap joints, which indicated the need for 
revised procedures and reduced compliance times. The Federal 
Aviation Administration is issuing this AD to detect and correct 
cracking of the fuselage skin lap splice between body station (BS) 
400 and BS 520, at stringers S-6L and S-6R. Such cracking could 
result in sudden loss of cabin pressurization and the inability of 
the fuselage to withstand fail-safe loads.

Compliance

    (f) 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 90-21-17, Amendment 39-6768, With 
Revised Service Information, Reduced Inspection Interval, and Added 
Note

Inspection

    (g) Conduct a close visual or detailed inspection, and a high 
frequency eddy current (HFEC) inspection, of the fuselage skin lap 
splice between BS 400 and BS 520, at stringers S-6L and S-6R, for 
cracking, in accordance with Boeing Alert Service Bulletin 747-
53A2303, dated June 2, 1988; Revision 1, dated March 29, 1990; or 
Revision 2, dated October 1, 2009; at the times specified in 
paragraph (g)(1), (g)(2), or (g)(3) of this AD. After the effective 
date of this AD, only Revision 2 may be used. Adequate lighting must 
be used for this inspection. The eddy current inspections may be 
conducted without removal of the paint, provided the paint does not 
interfere with the inspections. Paint must be removed, using an 
approved chemical stripper, in any situation where the inspector 
determines that the paint is interfering with the proper functioning 
of the inspection instrument.
    (1) Within the next 100 landings after March 31, 1989 (the 
effective date of Amendment 39-6146, AD 89-05-03, which was 
superseded by AD 90-21-17), for airplanes that have accumulated 
16,000 or more landings as of March 31, 1989, unless previously 
accomplished within the last 4,900 landings.
    (2) Within the next 1,000 landings after March 31, 1989, or 
prior to the accumulation of 16,000 landings, whichever occurs 
first, for airplanes that have accumulated between 12,000 and 16,000 
landings, as of March 31, 1989, unless previously accomplished 
within the last 4,000 landings.
    (3) Prior to the accumulation of 13,000 landings for airplanes 
that have accumulated 12,000 or fewer landings as of March 31, 1989, 
unless previously accomplished within the last 5,000 landings.

    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.''

    (h) On airplanes which have been modified to the stretched-
upper-deck configuration, as identified in Boeing Alert Service 
Bulletin 747-53A2303, dated June 2, 1988; or Revision 1, dated March 
29, 1990; or Boeing Service Bulletin 747-53A2303, Revision 2, dated 
October 1, 2009; the accumulated landing threshold for compliance 
with

[[Page 38077]]

paragraph (g) of this AD is measured from the time of the stretched-
upper-deck modification.
    (i) If no cracking is detected during the inspections required 
by paragraph (g) of this AD, repeat the inspections required by 
paragraph (g) of this AD one time at the earlier of the times 
specified in paragraphs (i)(1) and (i)(2) of this AD. Thereafter 
repeat the inspections at intervals not to exceed 3,000 landings.
    (1) Within 5,000 landings after the last inspection.
    (2) Within 3,000 landings after the last inspection, or within 
1,000 landings after the effective date of this AD, whichever occurs 
later.
    (j) If cracks are detected during the inspections required by 
paragraph (g) of this AD, accomplish the repair or preventive 
modification of the affected lap splice, in accordance with Boeing 
Alert Service Bulletin 747-53A2303, dated June 2, 1988; or Revision 
1, dated March 29, 1990; or Boeing Service Bulletin 747-53A2303, 
Revision 2, dated October 1, 2009; prior to further pressurized 
flight. After the effective date of this AD, only Revision 2 may be 
used. If cracks are repaired in local areas without accomplishing 
preventive modification of the entire affected lap area, continue 
inspections of the unmodified and unrepaired areas of the affected 
lap splice in accordance with paragraph (i) of this AD.
    (k) For airplanes incorporating the preventive modification, as 
described in Boeing Alert Service Bulletin 747-53A2303, dated June 
2, 1988; or Revision 1, dated March 29, 1990; or Boeing Service 
Bulletin 747-53A2303, Revision 2, dated October 1, 2009; accomplish 
the inspections required by paragraph (g) of this AD prior to the 
accumulation of 10,000 landings after the modification and 
thereafter at intervals not to exceed 5,000 landings. If cracks are 
found, repair in accordance with a method approved by the Manager, 
Seattle Aircraft Certification Office, FAA, Northwest Mountain 
Region, prior to further pressurized flight.

New Requirements of This AD

Post-Modification Inspections

    (l) For airplanes on which a protruding head fastener 
modification has been done in accordance with Boeing Alert Service 
Bulletin 747-53A2303, dated June 2, 1988; or Revision 1, dated March 
29, 1990: Within 10,000 flight cycles after modification, or within 
500 flight cycles after the effective date of this AD, whichever 
occurs later, do an external HFEC inspection for cracking in the 
skin around the fasteners in the upper row of the lap joint, in 
accordance with Part 5 of the Accomplishment Instructions of Boeing 
Service Bulletin 747-53A2303, Revision 2, dated October 1, 2009 
(``the service bulletin''). If any crack is found, before further 
flight repair in accordance with the service bulletin (except as 
required by paragraph (o) of this AD), or do the modification 
specified in paragraph (n) of this AD. Repeat the inspection in 
affected uncracked areas at intervals not to exceed 500 flight 
cycles, until the modification specified in paragraph (n) of this AD 
is done.
    (m) For airplanes on which an external doubler repair has been 
installed as a modification that was done in accordance with a 
method other than that specified in Boeing 747 SRM 53-30-03, Figure 
19, 25, 28 or 34: Within 10,000 flight cycles after modification, or 
within 500 flight cycles after the effective date of this AD, 
whichever occurs later, do an internal HFEC inspection for cracking 
in the skin around the fasteners in the upper row of the lap joint, 
in accordance with Part 5 of the Accomplishment Instructions of 
Boeing Service Bulletin 747-53A2303, Revision 2, dated October 1, 
2009 (``the service bulletin''). If any crack is found, before 
further flight, repair in accordance with the service bulletin 
(except as required by paragraph (o) of this AD), or do the 
modification specified in paragraph (n) of this AD. Repeat the 
inspection in affected uncracked areas at intervals not to exceed 
500 flight cycles, until the modification specified in paragraph (n) 
of this AD is done.

External Doubler Modification

    (n) For airplanes on which no previous modification or repair 
has been installed in the affected area or on which a protruding 
head fastener modification or a Boeing 747 SRM 53-30-03 repair or 
modification has been installed that is not per Figure 19, 25, 28, 
or 34 of the Boeing 747 SRM for the full length of the lap splice: 
Within 14,000 flight cycles after the first repair or modification 
was done, or within 3,000 flight cycles after the effective date of 
this AD, whichever occurs later, modify the skin, and do all post-
modification inspections and repairs, in accordance with Part 3 of 
Boeing Service Bulletin 747-53A2303, Revision 2, dated October 1, 
2009, except as required by paragraph (o) of this AD. Do the post-
modification inspection within 10,000 flight cycles after 
installation of the modification. Repeat the inspection thereafter 
at intervals not to exceed 3,000 flight cycles. All applicable 
repairs must be done before further flight.

Exception to Service Bulletin Specification

    (o) Where Boeing Service Bulletin 747-53A2303, Revision 2, dated 
October 1, 2009, specifies to contact Boeing for appropriate action: 
Before further flight, repair using a method approved in accordance 
with the procedures specified in paragraph (p) of this AD.

Alternative Methods of Compliance (AMOCs)

    (p)(1) The Manager, Seattle Aircraft Certification Office (ACO), 
FAA, has the authority to approve AMOCs for this AD, if requested 
using the procedures found in 14 CFR 39.19. In accordance with 14 
CFR 39.19, send your request to your principal inspector or local 
Flight Standards District Office, as appropriate. If sending 
information directly to the manager of the ACO, send it to the 
attention of the person identified in the Related Information 
section of this AD. Information may be e-mailed to: 9-ANM-Seattle-ACO-AMOC-Requests@faa.gov.
    (2) Before using any approved AMOC, notify your appropriate 
principal inspector, or lacking a principal inspector, the manager 
of the local flight standards district office/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 the 
Boeing Commercial Airplanes Organization Designation Authorization 
(ODA) or other person 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) AMOCs approved previously in accordance with AD 90-21-17 are 
approved as AMOCs for the corresponding provisions of paragraphs (g) 
and (i) of this AD. AMOCs approved previously in accordance with AD 
90-21-17 are approved as AMOCs for the corresponding provisions of 
paragraphs (j) and (n) of this AD only if the repair or preventive 
modification of the affected lap splice was done in accordance with 
Boeing Service Bulletin 747-53A2303, Revision 2, dated October 1, 
2009 (``the service bulletin''), including Boeing Designated 
Engineering Representative (DER) or Airworthiness Representative 
(AR) approvals of deviations to Revision 2 of the service bulletin.

Related Information

    (q) For more information about this AD, contact Bill Ashforth, 
Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft 
Certification Office (ACO), 1601 Lind Avenue, SW., Renton, 
Washington 98057-3356; telephone 425-917-6432; fax 425-917-6590; e-
mail: bill.ashforth@faa.gov.
    (r) For service information identified in this AD, contact 
Boeing Commercial Airplanes, Attention: Data & Services Management, 
P.O. Box 3707, MC 2H-65, Seattle, Washington 98124-2207; telephone 
206-544-5000, extension 1; fax 206-766-5680; e-mail 
me.boecom@boeing.com; Internet https://www.myboeingfleet.com. You 
may review copies of the referenced service information at the FAA, 
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington. For information on the availability of this material at 
the FAA, call 425-227-1221.

    Issued in Renton, Washington, on June 17, 2011.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2011-16370 Filed 6-28-11; 8:45 am]
BILLING CODE 4910-13-P


