
[Federal Register: April 21, 2010 (Volume 75, Number 76)]
[Proposed Rules]               
[Page 20792-20794]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr21ap10-16]                         

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2010-0383; Directorate Identifier 2009-NM-214-AD]
RIN 2120-AA64

 
Airworthiness Directives; The Boeing Company Model 747-100, 747-
100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 
747SR, and 747SP Series Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: We propose to adopt a new airworthiness directive (AD) for 
certain Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-
200F, 747-300, 747-400, 747SR, and 747SP series airplanes. This 
proposed AD would require repetitive detailed inspections of certain 
overwing intercostal webs, and related investigative and corrective 
actions if necessary. This proposed AD results from reports of cracks 
in overwing intercostal webs. We are proposing this AD to detect and 
correct such cracking, which could grow and result in a severed 
intercostal. If an intercostal is severed, cracks could develop in the 
adjacent frame structure and skin, resulting in a rapid loss of cabin 
pressure.

DATES: We must receive comments on this proposed AD by June 7, 2010.

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

[[Page 20793]]


FOR FURTHER INFORMATION CONTACT: Ivan Li, Aerospace Engineer, Airframe 
Branch, ANM-120S, FAA, Seattle Aircraft Certification Office (ACO), 
1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425) 
917-6437; fax (425) 917-6590.

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-2010-0383; 
Directorate Identifier 2009-NM-214-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://
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

    We have received several reports of cracks in overwing intercostal 
webs between station (STA) 1160 and STA 1220. Most of the cracks were 
found near the intercostal lower chord and a few cracks were found near 
the intercostal upper chord. The cracks ranged from 0.2 inch to 3.5 
inches long. The cracks are caused by cyclic buckling of the web from 
normal flight loads. The earliest report of a web crack occurred on an 
airplane with 3,697 flight cycles; however, no cracks have been 
reported in the upper or lower chord of the overwing intercostals. This 
condition, if not corrected, could result in crack growth and a severed 
intercostal. If an intercostal is severed, cracks could develop in the 
adjacent frame structure and skin, resulting in rapid loss of cabin 
pressure.

Relevant Service Information

    We have reviewed Boeing Alert Service Bulletin 747-53A2750, dated 
August 27, 2009. Boeing Alert Service Bulletin 747-53A2750, dated 
August 27, 2009, describes procedures for doing a repetitive detailed 
inspection for cracking of the left-side and right-side overwing 
intercostal webs at STAs 1160, 1180, 1200, and 1220, and related 
investigative and corrective actions if necessary. The related 
investigative action is doing a detailed inspection for cracking of the 
upper chord, lower chord, and stiffener of the intercostal and adjacent 
frame assembly structure if a crack is found in the web of an overwing 
intercostal. Depending on findings, the corrective actions are 
replacing any cracked overwing intercostal web (the replacement of the 
overwing intercostal web includes doing an open-hole HFEC inspection 
for cracking of the fastener holes common to the replacement); and 
contacting Boeing for repair instructions of any cracked intercostal 
upper chord, lower chord, stiffener, or adjacent frame assembly 
structure, and of any crack found during any open-hole HFEC 
inspections, and doing the repair.
    For any airplane having a STA 1160, 1180, 1200, or 1220 overwing 
intercostal web that has been replaced in accordance with this service 
bulletin, Boeing Alert Service Bulletin 747-53A2750, dated August 27, 
2009, specifies procedures for doing repetitive detailed inspections 
for cracking of the replaced web, and related investigative and 
corrective actions if necessary. Related investigative actions include 
doing a detailed inspection for cracking of the upper chord, lower 
chord, and stiffener of the intercostal, and adjacent frame assembly 
structure. Corrective actions include replacing any cracked overwing 
intercostal web; and contacting Boeing for repair instructions of any 
cracked intercostal upper chord, lower chord, stiffener, or adjacent 
frame assembly structure, and of any crack found during any open-hole 
HFEC inspections, and doing the repair.

FAA's Determination and Requirements of This Proposed AD

    We are proposing this AD because we evaluated all relevant 
information and determined the unsafe condition described previously is 
likely to exist or develop in other products of the same type design. 
This proposed AD would require accomplishing the actions specified in 
the service information described previously, except as discussed under 
``Differences Between the Proposed Rule and Service Bulletin.''

Differences Between the Proposed Rule and Service Bulletin

    Boeing Alert Service Bulletin 747-53A2750, dated August 27, 2009, 
specifies to contact 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.

Costs of Compliance

    We estimate that this proposed AD would affect 86 airplanes of U.S. 
registry. The following table provides the estimated costs for U.S. 
operators to comply with this proposed AD.

                                                                 Table--Estimated costs
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                   Number of U.S.-
              Action                  Work hours     Average labor           Parts             Cost per product      registered          Fleet cost
                                                     rate per hour                                                    airplanes
--------------------------------------------------------------------------------------------------------------------------------------------------------
Inspection........................               4             $85  None..................  $340 per inspection                86  $29,240 per
                                                                                             cycle                                  inspection 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

[[Page 20794]]

products identified in this rulemaking action.

Regulatory Findings

    We 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 this 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.
    You can find our regulatory evaluation and the estimated costs of 
compliance in the AD Docket.

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 adding the following new AD:

The Boeing Company: Docket No. FAA-2010-0383; Directorate Identifier 
2009-NM-214-AD.

Comments Due Date

    (a) We must receive comments by June 7, 2010.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to The Boeing Company Model 747-100, 747-
100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 
747SR, and 747SP series airplanes, certificated in any category; as 
identified in Boeing Alert Service Bulletin 747-53A2750, dated 
August 27, 2009.

Subject

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

Unsafe Condition

    (e) This AD results from reports of cracks in overwing 
intercostal webs between station (STA) 1160 and STA 1220. The 
Federal Aviation Administration is issuing this AD to detect and 
correct such cracking, which could grow and result in a severed 
intercostal. If an intercostal is severed, cracks could develop in 
the adjacent frame structure and skin, resulting in a rapid loss of 
cabin pressure.

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.

Repetitive Inspections of the Overwing Intercostal Web

    (g) Before the accumulation of 8,000 total flight cycles, or 
within 1,500 flight cycles after the effective date of this AD, 
whichever occurs later: Do a detailed inspection of the left-side 
and right-side STAs 1160, 1180, 1200, and 1220 overwing intercostal 
webs, and all applicable related investigative and corrective 
actions, in accordance with the Accomplishment Instructions of 
Boeing Alert Service Bulletin 747-53A2750, dated August 27, 2009, 
except as required by paragraph (i) of this AD. Do all applicable 
related investigative and corrective actions before further flight. 
If no cracking is found during any detailed inspection, repeat the 
inspection thereafter at intervals not to exceed 3,000 flight 
cycles.
    (h) For any airplane with an overwing intercostal web replaced 
in accordance with Boeing Alert Service Bulletin 747-53A2750, dated 
August 27, 2009: Within 6,000 flight cycles after the web was 
replaced, do a detailed inspection of the replacement overwing 
intercostal web, and do all applicable related investigative and 
corrective actions, in accordance with the Accomplishment 
Instructions of Boeing Alert Service Bulletin 747-53A2750, dated 
August 27, 2009, except as required by paragraph (i) of this AD. Do 
all applicable related investigative and corrective actions before 
further flight. If no cracking is found during any detailed 
inspection, repeat the inspection thereafter at intervals not to 
exceed 3,000 flight cycles.

Exception to Service Bulletin

    (i) If any cracking is found during any inspection required by 
this AD, and Boeing Alert Service Bulletin 747-53A2750, dated August 
27, 2009, specifies contacting Boeing for appropriate action: Before 
further flight, repair the cracking using a method approved in 
accordance with the procedures provided in paragraph (j) of this AD.

Alternative Methods of Compliance (AMOCs)

    (j)(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. Send information to 
ATTN: Ivan Li, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, 
Seattle Aircraft Certification Office (ACO), 1601 Lind Avenue, SW., 
Renton, Washington 98057-3356; telephone (425) 917-6437; fax (425) 
917-6590. Information may be e-mailed to: 9-ANM-Seattle-ACO-AMOC-
Requests@faa.gov.
    (2) To request a different method of compliance or a different 
compliance time for this AD, follow the procedures in 14 CFR 39.19. 
Before using any approved AMOC on any airplane to which the AMOC 
applies, notify your principal maintenance inspector (PMI) or 
principal avionics inspector (PAI), as appropriate, or lacking a 
principal inspector, your local Flight Standards District Office. 
The AMOC approval letter must specifically reference this AD.
    (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 
that 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.

    Issued in Renton, Washington, on April 9, 2010.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2010-9112 Filed 4-20-10; 8:45 am]
BILLING CODE 4910-13-P

