Document ID: FAA-2009-1066-0001
Agency: faa
Document Type: Rule
Title: Airworthiness Directives; Boeing Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-300, 747SR, and 747SP Series Airplanes
Posted Date: 2009-11-18T05:00Z

[Federal Register: November 18, 2009 (Volume 74, Number 221)]
[Proposed Rules]               
[Page 59488-59491]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr18no09-14]                         

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2009-1066; Directorate Identifier 2009-NM-028-AD]
RIN 2120-AA64

 
Airworthiness Directives; Boeing Model 747-100, 747-100B, 747-
100B SUD, 747-200B, 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 Boeing Model 747 series 
airplanes. The existing AD currently requires repetitive inspections to 
detect cracking in certain fuselage skin lap joints, and repair if 
necessary. This proposed AD would expand the inspection area in the 
existing AD, add a modification of certain lap joints, and add certain 
post-repair inspections of the lap joints. Accomplishing the 
modification would end the repetitive inspections required by the 
existing AD for the length of lap joint that is modified. This proposed 
AD results from a structural review of affected skin lap joints for 
widespread fatigue damage. We are proposing this AD to prevent fatigue 
cracking in certain lap joints, which could result in rapid 
depressurization of the airplane.

DATES: We must receive comments on this proposed AD by January 4, 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 or 
425-227-1152.

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-2009-1066; 
Directorate Identifier 2009-NM-028-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

[[Page 59489]]

personal information you provide. We will also post a report 
summarizing each substantive verbal contact we receive about this 
proposed AD.

Discussion

    On May 31, 1994, we issued AD 94-12-04, Amendment 39-8932 (59 FR 
30277, June 13, 1994), for certain Boeing Model 747 series airplanes. 
That AD requires repetitive inspections to detect cracking in certain 
fuselage skin lap joints, and repair, if necessary. That AD was 
prompted by the results of extensive pressure fatigue tests conducted 
by the manufacturer. We issued that AD to detect and repair fatigue 
cracking in certain lap joints, which will ensure safe operation of 
airplanes that have exceeded their economic design goal.

Actions Since Existing AD Was Issued

    Since we issued AD 94-12-04, the manufacturer has conducted a 
structural review of affected skin lap joints for widespread fatigue 
damage, and has identified additional inspection and modification 
requirements. It was determined that it is necessary to inspect lap 
joints with an upper skin thickness of 0.09 inch in addition to the 
areas inspected in accordance with the existing AD. For Model 747SP 
airplanes, the skin lap joints in Section 44 are also included in those 
inspections. It was determined that lap joints in Sections 41 and 42 
with an upper skin thickness of 0.071 inch or less should be modified; 
and post-repair inspections are necessary.

Revised Service Information

    We have reviewed Boeing Alert Service Bulletin 747-53A2367, 
Revision 2, dated October 30, 2008 (``Revision 2 of the service 
bulletin''); and Boeing Service Bulletin 747-53A2367, Revision 3, dated 
January 15, 2009 (``Revision 3 of the service bulletin''). We referred 
to Boeing Service Bulletin 747-53-2367, dated December 18, 1991 (``the 
original issue of the service bulletin''); and Boeing Service Bulletin 
747-53-2367, Revision 1, dated January 27, 1994 (``Revision 1 of the 
service bulletin''); as the appropriate sources of service information 
for accomplishing the actions required by AD 94-12-04.
    Revisions 2 and 3 of the service bulletin retain the procedures 
described in the original issue of the service bulletin and Revision 1 
of the service bulletin; however, those revisions add procedures for a 
new inspection area (Area 2) in Sections 41, 42, 44, and 46. Revisions 
2 and 3 of the service bulletin also add procedures for a modification 
of the lap joints in Sections 41 and 42 for Groups 1, 2, 4, 5, and 7 
through 10 airplanes. For airplanes on which any crack is found during 
the external surface high frequency eddy current (HFEC) inspection, the 
related investigative action is doing an open-hole HFEC inspection 
before further flight for further cracking; and for airplanes on which 
any crack is found, during that inspection, the corrective action is 
repairing the crack before further flight.
    The compliance time for accomplishing the new Area 2 inspections is 
before the accumulation of 22,000 total flight cycles, or within 3,000 
flight cycles after the last HFEC inspection of the area (as specified 
in the Boeing Model 747 Supplemental Structural Inspection Document), 
or within 1,000 flight cycles from the date on Revision 2 of the 
service bulletin, whichever occurs latest.
    The compliance time for accomplishing the inspections in Section 41 
at stringer 6 for Groups 2, 4, 8, and 9 airplanes not affected by 
Boeing Service Bulletin 747-53-2253 is within 10,000 flight cycles 
after doublers are installed per Boeing Service Bulletin 747-53-2272. 
These requirements are specified in AD 2008-10-15, Amendment 39-15522 
(73 FR 29042, May 20, 2008).
    For areas on which a lap joint repair was installed and the repair 
doubler is greater than or equal to 40 inches long, Revision 3 of the 
service bulletin describes procedures for repetitive internal surface 
HFEC inspections for cracks. The compliance time for accomplishing the 
initial inspection is within 15,000 flight cycles after the repair was 
installed.
    Revision 3 of the service bulletin specifies repeating the 
applicable inspection at intervals not to exceed 3,000 flight cycles, 
or at intervals not to exceed 1,500 flight cycles for airplanes that 
have accumulated 30,000 total flight cycles or more. For Group 7, 8, 
and 9 airplanes, the inspections of the lap joints in Section 46 at 
stringer 4 left, between body stations 1720 and 1740, and between body 
stations 1960 and 1980, are repeated at intervals not to exceed 1,500 
flight cycles.
    For all airplanes, the compliance time for accomplishing the lap 
joint modification is before the accumulation of 30,000 total flight 
cycles, or within 3,000 flight cycles from the date of Revision 2 of 
the service bulletin, whichever is later. Accomplishing this 
modification eliminates the need for the repetitive inspections for the 
length of lap joint that is modified.
    Revision 3 of the service bulletin also specifies that no lap joint 
modification instructions are included for Groups 3 and 6 airplanes and 
recommends contacting Boeing for modification instructions.

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 94-12-04 and would retain the requirements of the 
existing AD. This proposed AD would also require accomplishing the 
actions specified in the service information described previously, 
except as discussed under ``Differences Between the Proposed AD and 
Service Information.''

Differences Between the Proposed AD and Service Information

    Revision 3 of the service bulletin specifies to contact the 
manufacturer for instructions on how to repair or modify certain 
conditions, but this proposed AD would require those conditions be done 
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 an Authorized Representative 
for the Boeing Commercial Airplanes Delegation Option Authorization 
Organization whom we have authorized to make those findings.
    Revision 3 of the service bulletin recommends that the modification 
be done before the accumulation of 30,000 total flight cycles or within 
3,000 flight cycles after the release date of Revision 2 of the service 
bulletin, ``whichever is earlier.'' However, the manufacturer has 
informed us that an error was made in that compliance time and it 
should specify ``whichever occurs later.'' The correct compliance time 
is specified in paragraph (j) of this AD.

Changes to Existing AD

    This proposed AD would retain all requirements of AD 94-12-04. 
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:

[[Page 59490]]

                      Revised Paragraph Identifiers
------------------------------------------------------------------------
                                           Corresponding requirement in
       Requirement in  AD 94-12-04               this proposed AD
------------------------------------------------------------------------
Paragraphs (a), (b), and (c)............  Paragraph (g).
------------------------------------------------------------------------

    We have also revised paragraph (g)(2)(i) of this AD (paragraph 
(c)(1) of AD 94-12-04) to remove reference to Chapter 53-30-03 of the 
Boeing 747 Structural Repair Manual (SRM). Instead, that paragraph 
instructs operators to contact the FAA for repair instructions. We have 
also added a new Note 1 to specify that guidance on repairing any 
subject cracking can be found in Chapter 53-30-03 of the Boeing 747 
SRM.

Costs of Compliance

    There are about 209 airplanes of the affected design in the 
worldwide fleet. This proposed AD would affect about 69 airplanes of 
U.S. registry.
    The actions that are required by AD 94-12-04 and retained in this 
proposed AD take about 14 work hours per airplane, at an average labor 
rate of $80 per work hour. Based on these figures, the estimated cost 
of the currently required actions is $1,120 per airplane, per 
inspection cycle.
    The new proposed Area 2 inspections would take about 477 work hours 
per airplane, depending on airplane configuration, at an average labor 
rate of $80 per work hour. Based on these figures, the estimated cost 
of the new actions specified in this proposed AD for U.S. operators is 
between $38,160 and $2,633,040, or between $2,400 and $3,840 per 
airplane, per inspection cycle.
    The new proposed modification would take about 171 work hours per 
airplane, at an average labor rate of $80 per work hour. Required parts 
cost per airplane would be minimal. Based on these figures, the 
estimated cost of the new actions specified in this proposed AD for 
U.S. operators is $943,920, or $13,680, per airplane.

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 39-8932 (59 FR 
30277, June 13, 1994) and adding the following new AD:

Boeing: Docket No. FAA-2009-1066; Directorate Identifier 2009-NM-
028-AD.

Comments Due Date

    (a) The FAA must receive comments on this AD action by January 
4, 2010.

Affected ADs

    (b) This AD supersedes AD 94-12-04, Amendment 39-8932.

Applicability

    (c) This AD applies Boeing Model 747-100, 747-100B, 747-100B 
SUD, 747-200B, 747-300, 747SR, and 747SP series airplanes, 
certificated in any category, as identified in Boeing Service 
Bulletin 747-53A2367, Revision 3, dated January 15, 2009.

Subject

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

Unsafe Condition

    (e) This AD results from a structural review of affected skin 
lap joints for widespread fatigue damage. The Federal Aviation 
Administration is issuing this AD to prevent fatigue cracking in 
certain lap joints which could result in rapid depressurization 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.

Restatement of Requirements of AD 94-12-04, With Revised Service 
Information

Repetitive Inspections

    (g) For airplanes identified in Boeing Service Bulletin 747-53-
2367, dated December 18, 1991: Prior to the accumulation of 22,000 
full pressure flight cycles (or, if the external skin panel of an 
affected lap joint has been replaced, prior to the accumulation of 
22,000 full pressure flight cycles since skin replacement), or 
within 1,000 landings after July 13, 1994 (the effective date of AD 
94-12-04), whichever occurs later, perform an external surface high 
frequency eddy current (HFEC) inspection of the skin around the 
upper row of fasteners, in accordance with the Accomplishment 
Instructions of Boeing Service Bulletin 747-53-2367, dated December 
18, 1991; Revision 1, dated January 27, 1994; Boeing Alert Service 
Bulletin 747-53A2367, Revision 2, dated October 30, 2008; or Boeing 
Service Bulletin 747-53A2367, Revision 3, dated January 15, 2009. As 
of the effective date of this AD, only Revision 3 of the service 
bulletin may be used.
    (1) If no crack is found, repeat the inspection thereafter at 
intervals not to exceed 3,000 full pressure flight cycles until the 
inspections required by paragraph (h) of this AD are done.
    (2) If any crack is found, accomplish paragraphs (g)(2)(i) and 
(g)(2)(ii) of this AD.
    (i) Prior to further flight, perform an open hole HFEC 
inspection to detect cracking in the upper row fastener holes 
between the adjacent frames, in accordance with the Accomplishment 
Instructions of Boeing Service Bulletin 747-53-2367, dated December 
18, 1991; Revision 1, dated January 27, 1994; Boeing Alert Service 
Bulletin 747-53A2367, Revision 2, dated October 30, 2008; or Boeing 
Service Bulletin 747-53A2367, Revision 3, dated January 15, 2009. 
Prior to further flight, repair any crack found, in accordance with 
a method approved by the

[[Page 59491]]

Manager, Seattle Aircraft Certification Office (ACO), FAA.

    Note 1:  Guidance on repairing cracking can be found in Chapter 
53-30-03 of the Boeing 747 Structural Repair Manual.

    (ii) Repeat the inspection required by paragraph (g) of this AD 
thereafter at intervals not to exceed 3,000 full pressure flight 
cycles until the inspections required by paragraph (h) of this AD 
are done.

New Requirements of This AD

Repetitive Inspections/Investigative and Corrective Actions

    (h) For all airplanes: Do initial and repetitive HFEC 
inspections for cracks of lap joints in Sections 41, 42, 44, and 46, 
by doing all the actions, including all applicable related 
investigative and corrective actions, specified in the 
Accomplishment Instructions of Boeing Service Bulletin 747-53A2367, 
Revision 3, dated January 15, 2009, except as provided by paragraph 
(l) of this AD. Do the inspections at the applicable times specified 
in paragraph 1.E. of Boeing Service Bulletin 747-53A2367, Revision 
3, dated January 15, 2009, except as required by paragraph (k) of 
this AD. Do all applicable related investigative and corrective 
actions before further flight. Accomplishing the inspections 
required by this paragraph ends the repetitive inspections required 
by paragraph (g) of this AD. Do the actions required by paragraph 
(h) of this AD until the modification required by paragraph (j) of 
this AD is done.
    (i) For areas on which a lap joint repair was installed and the 
repair doubler is greater than or equal to 40 inches long: Do 
initial and repetitive internal HFEC inspections for cracks, as 
required by paragraph (h) of this AD, by doing all the applicable 
actions, including applicable corrective actions, specified in the 
Accomplishment Instructions of Boeing Service Bulletin 747-53A2367, 
Revision 3, dated January 15, 2009, except as provided by paragraph 
(l) of this AD. Do the inspection and corrective actions at the 
times specified in paragraph 1.E. of Boeing Service Bulletin 747-
53A2367, Revision 3, dated January 15, 2009, except as required by 
paragraph (k) of this AD.

Terminating Action

    (j) Before the accumulation of 30,000 total flight cycles or 
within 3,000 flight cycles after the effective date of this AD, 
whichever occurs later: Modify the applicable lap joints in Sections 
41 and 42 by doing all the actions specified in the Accomplishment 
Instructions of Boeing Service Bulletin 747-53A2367, Revision 3, 
dated January 15, 2009, except as required by paragraph (l) of this 
AD. Accomplishing this modification terminates the repetitive 
inspection requirements of this AD for the length of lap joint that 
is modified.

Exceptions to Boeing Service Bulletin 747-53A2367, Revision 3

    (k) Where Boeing Service Bulletin 747-53A2367, Revision 3, dated 
January 15, 2009, specifies compliance times ``from the date on the 
original issue of this service bulletin [12/18/91],'' and ``from the 
date on Revision 2 of this service bulletin [10/30/08],'' this AD 
requires compliance within the specified compliance time after the 
effective date of this AD.
    (l) Where Boeing Service Bulletin 747-53A2367, Revision 3, dated 
January 15, 2009, specifies to contact Boeing for repair or 
modification instructions: Before further flight, repair or modify 
using a method approved in accordance with the procedures specified 
in paragraph (m) of this AD.

Alternative Methods of Compliance (AMOCs)

    (m)(1) The Manager, Seattle ACO, 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 ACO, 1601 Lind Avenue, SW., 
Renton, Washington 98057-3356; telephone (425) 917-6437; fax (425) 
917-6590. Or, e-mail information 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 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) AMOCs approved previously in accordance with AD 94-12-04 are 
approved as alternative methods of compliance with the corresponding 
requirements of this AD.

    Issued in Renton, Washington, on November 6, 2009.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. E9-27632 Filed 11-17-09; 8:45 am]

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