
[Federal Register: July 8, 2010 (Volume 75, Number 130)]
[Proposed Rules]               
[Page 39189-39192]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr08jy10-26]                         

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2010-0674; Directorate Identifier 2010-NM-012-AD]
RIN 2120-AA64

 
Airworthiness Directives; The Boeing Company Model 747 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 all 
Model 747 airplanes. This proposed AD would require repetitive 
inspections for cracking in the body skin around the aft corners of the 
nose wheel well; for certain airplanes, repetitive inspections for 
cracking in the skin splice plate at the aft corners of the nose wheel 
well; and related investigative and corrective actions if necessary. 
This proposed AD would also require repetitive post-modification 
inspections for cracking in the body skin and the skin splice plate; 
for certain airplanes, an inspection for steel cross-shaped doublers on 
the larger aluminum doublers; and corrective action if necessary. This 
proposed AD would also require repetitive surface high frequency eddy 
current (HFEC) inspections of a certain bulkhead outer chord, skin 
splice plate, and outer chord radius filler for cracking; repetitive 
detailed inspections for cracking of the bulkhead frame web and body 
skin; and corrective actions if necessary. This proposed AD would 
provide for optional terminating action for certain repetitive 
inspections. This proposed AD results from reports of cracking of the 
fuselage skin and adjacent internal skin splice plate at the left and 
right nose wheel well aft corners, and the outer chord of the body 
station (BS) 400 bulkhead. We are proposing this AD to detect and 
correct cracking of the fuselage skin or splice plate, which, together 
with cracking of the bulkhead outer chord, could result in large skin 
cracks and subsequent in-flight rapid decompression of the airplane.

DATES: We must receive comments on this proposed AD by August 23, 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.

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:

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-2010-0674; 
Directorate Identifier 2010-NM-012-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 reports of cracking of the fuselage skin and 
adjacent internal skin splice plate at the left and right nose wheel 
well aft corners, and the outer chord of the body station (BS) 400 
bulkhead. Cracks were found in the skin on an airplane that had 
accumulated about 6,355 total flight cycles. In addition, small cracks 
were found in the outer chord of the body station (BS) 400 bulkhead on 
airplanes that had accumulated fewer than 20,000 total flight cycles. 
Cracking of the fuselage skin or splice plate, together with cracking 
of the bulkhead outer chord, if not detected and corrected, could 
result in large skin cracks and subsequent in-flight rapid 
decompression of the airplane.

Relevant Service Information

    We have reviewed Boeing Alert Service Bulletin 747-53A2305, 
Revision 2, dated January 15, 2009. The service bulletin describes 
procedures for repetitive external detailed inspections for cracking in 
the body skin around the aft corners of the nose wheel well; for 
certain airplanes, repetitive external detailed inspections for 
cracking in the skin splice plate at the aft corners of the nose wheel 
well, and modification of any cracked aft corners of the nose wheel 
well by installing modification doublers; and, for certain airplanes, 
and a one-time external general visual inspection for steel cross-
shaped doublers. The modification, which, if accomplished to repair 
cracks or to eliminate the need for certain repetitive inspections, 
includes related investigative actions and corrective actions if 
necessary. The related investigative actions include an open-hole HFEC 
inspection for cracking at fasteners common to the bulkhead outer 
chord, and a surface HFEC inspection or penetrant inspection for 
cracking of the skin if necessary. The corrective actions include 
repairing the crack, installing cross-shaped doublers, and contacting 
Boeing for repair instructions and doing the repair.

[[Page 39190]]

    The service bulletin also describes procedures for repetitive post-
modification inspections, which consist of an external low frequency 
eddy current (LFEC) inspection for cracking in the skin around 
fasteners at the periphery of modification doublers, and contacting 
Boeing for instructions to repair cracks and doing the repair. The 
service bulletin also describes procedures for repetitive surface HFEC 
inspections for cracking of a certain bulkhead outer chord, skin splice 
plate, and outer chord radius filler; repetitive detailed inspections 
for cracking of the bulkhead frame web and body skin, and corrective 
actions if necessary. The corrective actions include repairing the 
crack, or contacting Boeing for repair instructions and repairing if 
necessary.

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 described 
below.

Differences Between Proposed Rule and Service Bulletin

    Boeing Service Bulletin 747-53A2305, Revision 2, dated January 15, 
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 160 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
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                          Average labor     Cost per       Number of  U.S.-registered
                 Action                    Work hours     rate per hour      product                airplanes                       Fleet cost
--------------------------------------------------------------------------------------------------------------------------------------------------------
Inspections: Body skin and skin splice                1             $85             $85  160...........................  $13,600.
 plate.
Modification: Groups 1-3 \1\...........             180              85          15,300  Up to 27......................  Up to $413,100.
Modification: Groups 1-3 \2\...........             320              85          27,200  Up to 27......................  Up to $734,400.
Modification: Groups 4-8 \3\...........             180              85          15,300  Up to 133.....................  Up to $2,034,900.
Modification: Groups 4-7 \4\...........              40              85           3,400  Up to 44......................  Up to $149,600.
Post-Mod LFEC Inspection \5\...........               6              85             510  Up to 160.....................  Up to $81,600.
Inspections: Bulkhead Outer Chord \6\..               4              85             340  Up to 160.....................  Up to $54,400.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Installation of skin and splice plate doubler for Groups 1-3 airplanes that have not done Boeing Service Bulletin 747-53-2150 or Figure 35 of
  Section 53-30-03 of the Boeing 747 Structural Repair Manual.
\2\ Installation of skin and splice plate doubler for Groups 1-3 airplanes that have done Boeing Service Bulletin 747-53-2150 or Figure 35 of Section 53-
  30-03 of the Boeing 747 Structural Repair Manual.
\3\ Installation of skin and splice plate doubler for Groups 4-8 airplanes.
\4\ Installation of splice plate doubler for Groups 4-7 airplanes changed before Boeing Alert Service Bulletin 747-53A2305, Revision 2, dated January
  15, 2009.
\5\ Inspection for skin cracks around the fasteners at the periphery of the modification doublers.
\6\ Includes inspection of the frame web and body skin.

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 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-2010-0674; Directorate Identifier 
2010-NM-012-AD.

[[Page 39191]]

Comments Due Date

    (a) We must receive comments by August 23, 2010.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to all The Boeing Company Model 747-100, 
747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-
400, 747-400D, 747-400F, 747SR, and 747SP series airplanes, 
certificated in any category.

Subject

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

Unsafe Condition

    (e) This AD results from reports of cracking of the fuselage 
skin and adjacent internal skin splice plate at the left and right 
nose wheel well aft corners, and the outer chord of the body station 
(BS) 400 bulkhead. The Federal Aviation Administration is issuing 
this AD to detect and correct cracking of the fuselage skin or 
splice plate, which, together with cracking of the bulkhead outer 
chord, could result in large skin cracks and subsequent in-flight 
rapid decompression of the airplane.

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.

Pre-Modification Inspections

    (g) For airplanes in Groups 1 through 3, as identified in Boeing 
Alert Service Bulletin 747-53A2305, Revision 2, dated January 15, 
2009, that have not been modified in accordance with Boeing Service 
Bulletin 747-53-2150; have not been repaired in accordance with 
Figure 35 of Section 53-30-03 of Boeing 747 Structural Repair Manual 
(SRM); and have not been modified in accordance with Boeing Alert 
Service Bulletin 747-53A2305: Before the accumulation of 3,000 total 
flight cycles, or within 1,500 flight cycles after the effective 
date of this AD, whichever occurs later, do an external detailed 
inspection for cracks in the body skin around the aft corners of the 
nose wheel well, and skin splice plate at the aft corners of the 
nose wheel well, in accordance with the Accomplishment Instructions 
of Boeing Alert Service Bulletin 747-53A2305, Revision 2, dated 
January 15, 2009.
    (h) For airplanes in Groups 1 through 3, as identified in Boeing 
Alert Service Bulletin 747-53A2305, Revision 2, dated January 15, 
2009, that have been modified in accordance with Boeing Service 
Bulletin 747-53-2150; or repaired in accordance with Boeing 747 
Figure 35 of Section 53-30-03 of Boeing 747 SRM: Within 6,000 flight 
cycles after doing the modification or repair, or within 1,500 
flight cycles after the effective date of this AD, whichever occurs 
later, do an external detailed inspection for cracks in the body 
skin around the aft corners of the nose wheel well, and skin splice 
plate at the aft corners of the nose wheel well, in accordance with 
the Accomplishment Instructions of Boeing Alert Service Bulletin 
747-53A2305, Revision 2, dated January 15, 2009.
    (i) For airplanes in Groups 4 through 7, as identified in Boeing 
Alert Service Bulletin 747-53A2305, Revision 2, dated January 15, 
2009, that have not been modified in accordance with Boeing Alert 
Service Bulletin 747-53A2305: Prior to the accumulation of 3,000 
total flight cycles, or within 1,500 flight cycles after the 
effective date of this AD, whichever occurs later, do an external 
detailed inspection for cracks in the body skin around the aft 
corners of the nose wheel well, in accordance with the 
Accomplishment Instructions of Boeing Alert Service Bulletin 747-
53A2305, Revision 2, dated January 15, 2009.
    (j) For airplanes in Groups 4 through 7, as identified in Boeing 
Alert Service Bulletin 747-53A2305, Revision 2, dated January 15, 
2009, that have been modified in accordance with Boeing Service 
Bulletin 747-53-2305, dated June 27, 1991; or Revision 1, dated May 
22, 1997: Within 1,000 flight cycles after the effective date of 
this AD, do a one-time external general visual inspection for steel 
cross-shaped doublers, in accordance with the Accomplishment 
Instructions of Boeing Alert Service Bulletin 747-53A2305, Revision 
2, dated January 15, 2009. If no cross-shaped doublers are 
installed, within 1,500 flight cycles after the effective date of 
this AD, install cross-shaped doublers, in accordance with the 
Accomplishment Instructions of Boeing Alert Service Bulletin 747-
53A2305, Revision 2, dated January 15, 2009.
    (k) For airplanes in Group 8, as identified in Boeing Alert 
Service Bulletin 747-53A2305, Revision 2, dated January 15, 2009: 
Prior to the accumulation of 3,000 total flight cycles, or within 
1,500 flight cycles after the effective date of this AD, whichever 
occurs later, do an external detailed inspection for cracks in the 
body skin around the aft corners of the nose wheel well, in 
accordance with the Accomplishment Instructions of Boeing Alert 
Service Bulletin 747-53A2305, Revision 2, dated January 15, 2009.
    (l) If no crack is found during any inspection required by 
paragraph (g), (h), (i), or (k) of this AD, repeat the applicable 
inspection specified in paragraph (g), (h), (i), or (k) of this AD 
thereafter at intervals not to exceed 1,500 flight cycles, until the 
modification specified in paragraph (n) of this AD is accomplished.
    (m) If any crack is found during any inspection required by 
paragraph (g), (h), (i), (k), or (l) of this AD, before further 
flight, modify the aft corners of the nose wheel well by installing 
modification doublers and doing all applicable related investigative 
and corrective actions, in accordance with the Accomplishment 
Instructions of Boeing Alert Service Bulletin 747-53A2305, Revision 
2, dated January 15, 2009, except as required by paragraph (t) of 
this AD.

Optional Terminating Action

    (n) Modification of the aft corners of the nose wheel well by 
installing modification doublers and doing all applicable related 
investigative and corrective actions, in accordance with the 
Accomplishment Instructions of Boeing Alert Service Bulletin 747-
53A2305, Revision 2, dated January 15, 2009, terminates the 
repetitive inspections required by paragraph (l) of this AD for the 
modified side only. Where Boeing Alert Service Bulletin 747-53A2305, 
Revision 2, dated January 15, 2009, specifies to contact Boeing for 
appropriate action, repair using a method approved in accordance 
with the procedures specified in paragraph (u) of this AD.

Post-Modification Repetitive Inspections

    (o) For airplanes on which the modification specified in Boeing 
Alert Service Bulletin 747-53A2305, Revision 2, dated January 15, 
2009, has been done: At the applicable time specified in paragraph 
(o)(1) or (o)(2) of this AD, do an external low frequency eddy 
current inspection for skin cracks around the fasteners at the 
periphery of the modification doublers, in accordance with the 
Accomplishment Instructions of Boeing Alert Service Bulletin 747-
53A2305, Revision 2, dated January 15, 2009.
    (1) For airplanes on which the edge row fastener holes common to 
the external modification doublers have been zero-timed in 
accordance with the Accomplishment Instructions of Boeing Alert 
Service Bulletin 747-53A2305, Revision 2, dated January 15, 2009: 
Within 15,000 flight cycles after accomplishing the modification, or 
within 1,500 flight cycles after the effective date of this AD, 
whichever occurs later.
    (2) For airplanes on which the edge row fastener holes common to 
the external modification doublers have not been zero-timed in 
accordance with the Accomplishment Instructions of Boeing Alert 
Service Bulletin 747-53A2305, Revision 2, dated January 15, 2009: 
Prior to the accumulation of 15,000 total flight cycles, or within 
1,500 flight cycles after the effective date of this AD, whichever 
occurs later.
    (p) If no cracking is found during the inspection required by 
paragraph (o) of this AD, repeat the inspection specified in 
paragraph (o) of this AD thereafter at intervals not to exceed 1,500 
flight cycles.
    (q) If any cracking is found during any inspection required by 
paragraph (o) or (p) of this AD, before further flight, repair using 
a method approved in accordance with the procedures specified in 
paragraph (u) of this AD.

Body Station (BS) 400 Bulkhead Outer Chord Inspection

    (r) For all airplanes: At the latest of the times specified in 
paragraphs (r)(1), (r)(2), and (r)(3) of this AD, do a surface HFEC 
for cracking in the BS 400 bulkhead outer chord, skin splice plate, 
and outer chord radius filler; and a detailed inspection for 
cracking of the bulkhead frame web and body skin; in accordance with 
the Accomplishment Instructions of Boeing Alert Service Bulletin 
747-53A2305, Revision 2, dated January 15, 2009. If no cracking is 
found during any inspection, repeat the inspection one time within 
6,000 flight cycles, and thereafter at intervals not to exceed 3,000 
flight cycles.
    (1) Before the accumulation of 20,000 total flight cycles.
    (2) Within 3,000 flight cycles after doing the HFEC inspection 
required by AD 2004-

[[Page 39192]]

07-22 R1, Amendment 39-15326, for structural significant item (SSI) 
F-4B of the Boeing Document No. D6-35022, ``Supplemental Structural 
Inspection Document (SSID) for Model 747 Airplanes,'' Revision G, 
dated December 2000.
    (3) Within 1,500 flight cycles after the effective date of this 
AD.
    (s) If any cracking is found during any inspection required by 
paragraph (r) of this AD, before further flight, repair in 
accordance with the Accomplishment Instructions of Boeing Alert 
Service Bulletin 747-53A2305, Revision 2, dated January 15, 2009, 
except as required by paragraph (t) of this AD. Within 6,000 flight 
cycles after doing the repair, do the inspections specified in 
paragraph (r) of this AD, and repeat the inspections thereafter at 
intervals not to exceed 3,000 flight cycles.

Service Bulletin Exception

    (t) If any cracking is found during any inspection required by 
this AD, and Boeing Alert Service Bulletin 747-53A2305, Revision 2, 
dated January 15, 2009, specifies to contact Boeing for appropriate 
action: Before further flight, repair the crack using a method 
approved in accordance with the procedures specified in paragraph 
(u) of this AD.

Alternative Methods of Compliance (AMOCs)

    (u)(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, 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 
(ODA) 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 June 29, 2010.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2010-16551 Filed 7-7-10; 8:45 am]
BILLING CODE 4910-13-P

