[Federal Register Volume 68, Number 24 (Wednesday, February 5, 2003)]
[Rules and Regulations]
[Pages 5805-5808]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 03-2210]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2002-NM-316-AD; Amendment 39-13044; AD 2003-03-19]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment adopts a new airworthiness directive (AD) that 
is applicable to all Boeing Model 747 series airplanes. This action 
requires a one-time inspection of the fuselage skin of the aft lower 
body for certain repair doublers, and follow-on inspections and 
corrective actions if such doublers are installed. For certain 
airplanes, this action includes optional repetitive inspections of the 
fuselage skin for scratches or cracking. This action is necessary to 
find and fix possible fatigue cracking of the fuselage skin concealed 
under certain repair doublers, which could result in rapid 
decompression of the airplane. This action is intended to address the 
identified unsafe condition.

DATES: Effective February 20, 2003.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of February 20, 2003.
    Comments for inclusion in the Rules Docket must be received on or 
before April 7, 2003.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2002-NM-316-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. Comments may be inspected at this 
location between 9 a.m. and 3 p.m., Monday through Friday, except 
Federal holidays. Comments may be submitted via fax to (425) 227-1232. 
Comments may also be sent via the Internet using the following address: 
[email protected]. Comments sent via fax or the Internet must 
contain ``Docket No. 2002-NM-316-AD'' in the subject line and need not 
be submitted in triplicate. Comments sent via the Internet as attached 
electronic files must be formatted in Microsoft Word 97 for Windows or 
ASCII text.
    The service information referenced in this AD may be obtained from 
Boeing Commercial Airplane Group, PO Box 3707, Seattle, Washington 
98124-2207. This information may be examined at the FAA, Transport 
Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at 
the Office of the Federal Register, 800 North Capitol Street, NW., 
suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Rick Kawaguchi, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 
227-1153; fax (425) 227-1181.

SUPPLEMENTARY INFORMATION: In May 2002, a Boeing Model 747-200 series 
airplane was involved in an in-flight breakup. A portion of the 
fuselage skin with a repair doubler attached was recovered, and 
investigation revealed that the repair doubler was installed after a 
tail strike that occurred in 1980 and caused scratches to the skin. 
Examination of the skin underneath the doubler revealed longitudinal 
scratches, which could have been caused by the tail strike event, and a 
15-inch crack found underneath the repair doubler that originated from 
and extended along these scratches. Further investigation of the 
affected area revealed that certain damage (scratches) may not have 
been found and removed after the tail strike, which led to fatigue 
cracking over time. The probable cause of the accident has not yet been 
determined.
    The FAA recently received a second report indicating that scratches 
were found under a repair doubler on a Model 747-200 series airplane 
during an inspection requested by the manufacturer. It has been 
determined that the aft ``belly'' portion of the section 46 fuselage on 
Model 747 series airplanes is susceptible to tail strike damage during 
landing and takeoff. Repair procedures in the Boeing 747 structural 
repair manual describe blending out such damage on the skin and 
installing a repair doubler over the affected area. Any unremoved 
damage could result in fatigue cracking of the fuselage skin concealed 
under certain repair doublers, and consequent rapid decompression of 
the airplane.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Alert Service Bulletin 
747-53A2489, dated November 26, 2002, which describes procedures for a 
one-time external visual inspection of the fuselage skin at body 
stations 1961 through 2360 inclusive, between stringers S-46L and S-
46R, for repair doublers. If a repair doubler is installed, and the 
repair doubler meets all four criteria (external repair doubler, at 
least 8 inches long longitudinally (in the forward and aft direction), 
has fasteners common to a frame, and was installed due to a tail strike 
or for unknown reasons) specified in Figure 2 of the service bulletin, 
the service bulletin describes procedures for follow-on inspections and 
corrective actions.
    The follow-on inspections and corrective actions include removal of 
the doubler, a one-time assessment (inspection) of the skin under the 
doubler for damage (scratches, cracking), and repair of any damage 
found. For certain airplanes, as an alternative to removal of the 
doubler and assessment of the skin underneath, the service bulletin 
describes procedures for repetitive inspections of the fuselage skin 
for damage. These inspections are either internal mid-frequency eddy 
current, or external

[[Page 5806]]

detailed visual, depending on the length of the doubler. Accomplishment 
of the actions specified in the service bulletin is intended to 
adequately address the identified unsafe condition.
    The service bulletin also specifies contacting Boeing for 
disposition of certain repair conditions.

Explanation of the Requirements of the Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other 747 series airplanes of the same type design, 
this AD is being issued to find and fix possible fatigue cracking of 
the fuselage skin concealed under certain repair doublers, which could 
result in rapid decompression of the airplane. This AD requires a one-
time inspection of the fuselage skin of the aft lower body for repair 
doublers, and follow-on inspections and corrective actions if repair 
doublers are installed. This AD also includes optional repetitive 
inspections of the fuselage skin for scratches or cracking. The actions 
are required to be accomplished in accordance with the service bulletin 
described previously, except as discussed below.

Differences Between Service Bulletin and This AD

    The service bulletin specifies an inspection of the fuselage skin 
between stringers S-46L and S-46R for the presence of doublers. 
However, the FAA has determined that repairs common to the S-46 lap 
splice that do not extend inboard more than 4 inches from the S-46 
center line do not require the inspection. Tail strike damage would 
more likely occur towards the ``belly'' portion of the section 46 
fuselage. Repairs limited to the S-46 lap splice area are probably due 
to corrosion findings. The manufacturer agrees with this determination 
and will incorporate this change into the next revision of Boeing Alert 
Service Bulletin 747-53A2489.
    The service bulletin also specifies that the manufacturer may be 
contacted for disposition of certain repair conditions, but this AD 
would require the repair of those conditions to be accomplished in 
accordance with a method approved by the FAA, or in accordance with 
data meeting the type certification basis of the airplane approved by a 
Boeing Company Designated Engineering Representative who has been 
authorized by the FAA to make such findings.

Interim Action

    This is considered to be interim action. The FAA is currently 
considering further rulemaking action to revise the compliance time of 
this AD to include airplanes that have accumulated more than 10,000 
total flight cycles, but less than 15,000 total flight cycles; however, 
the planned compliance time for the additional airplanes is 
sufficiently long so that notice and opportunity for prior public 
comment will be practicable.

Determination of Rule's Effective Date

    Since a situation exists that requires the immediate adoption of 
this regulation, it is found that notice and opportunity for prior 
public comment hereon are impracticable, and that good cause exists for 
making this amendment effective in less than 30 days.

Comments Invited

    Although this action is in the form of a final rule that involves 
requirements affecting flight safety and, thus, was not preceded by 
notice and an opportunity for public comment, comments are invited on 
this rule. Interested persons are invited to comment on this rule by 
submitting such written data, views, or arguments as they may desire. 
Communications shall identify the Rules Docket number and be submitted 
in triplicate to the address specified under the caption ADDRESSES. All 
communications received on or before the closing date for comments will 
be considered, and this rule may be amended in light of the comments 
received. Factual information that supports the commenter's ideas and 
suggestions is extremely helpful in evaluating the effectiveness of the 
AD action and determining whether additional rulemaking action would be 
needed.
    Submit comments using the following format:
    [sbull] Organize comments issue-by-issue. For example, discuss a 
request to change the compliance time and a request to change the 
service bulletin reference as two separate issues.
    [sbull] For each issue, state what specific change to the AD is 
being requested.
    [sbull] Include justification (e.g., reasons or data) for each 
request.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the rule that might 
suggest a need to modify the rule. All comments submitted will be 
available, both before and after the closing date for comments, in the 
Rules Docket for examination by interested persons. A report that 
summarizes each FAA-public contact concerned with the substance of this 
AD will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this rule must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 2002-NM-316-AD.'' The postcard will be date stamped 
and returned to the commenter.

Regulatory Impact

    The regulations adopted herein will not have a substantial direct 
effect on the States, on the relationship between the national 
Government and the States, or on the distribution of power and 
responsibilities among the various levels of government. Therefore, it 
is determined that this final rule does not have federalism 
implications under Executive Order 13132.
    The FAA has determined that this regulation is an emergency 
regulation that must be issued immediately to correct an unsafe 
condition in aircraft, and that it is not a ``significant regulatory 
action'' under Executive Order 12866. It has been determined further 
that this action involves an emergency regulation under DOT Regulatory 
Policies and Procedures (44 FR 11034, February 26, 1979). If it is 
determined that this emergency regulation otherwise would be 
significant under DOT Regulatory Policies and Procedures, a final 
regulatory evaluation will be prepared and placed in the Rules Docket. 
A copy of it, if filed, may be obtained from the Rules Docket at the 
location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends part 39 of 
the Federal Aviation Regulations (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. Section 39.13 is amended by adding the following new 
airworthiness directive:

2003-03-19 Boeing: Amendment 39-13044. Docket 2002-NM-316-AD.

    Applicability: All Model 747 series airplanes, certificated in 
any category.


[[Page 5807]]


    Note 1: This AD applies to each airplane identified in the 
preceding applicability provision, regardless of whether it has been 
modified, altered, or repaired in the area subject to the 
requirements of this AD. For airplanes that have been modified, 
altered, or repaired so that the performance of the requirements of 
this AD is affected, the owner/operator must request approval for an 
alternative method of compliance in accordance with paragraph (i) of 
this AD. The request should include an assessment of the effect of 
the modification, alteration, or repair on the unsafe condition 
addressed by this AD; and, if the unsafe condition has not been 
eliminated, the request should include specific proposed actions to 
address it.

    Compliance: Required as indicated, unless accomplished 
previously.
    To find and fix possible fatigue cracking of the fuselage skin 
concealed under certain repair doublers, which could result in rapid 
decompression of the airplane, accomplish the following:

One-Time Inspection

    (a) Before the accumulation of 15,000 total flight cycles or 
within 90 days after the effective date of this AD, whichever is 
later, do a general visual inspection for repair doublers on the 
fuselage skin at body stations 1961 through 2360 inclusive, between 
stringers S-46L and S-46R. The inspection is only for doublers that 
meet all of the following four criteria: External repair doublers, 
doublers at least 8 inches long longitudinally (in the forward and 
aft direction), doublers that have fasteners common to a frame, 
doublers installed due to a tail strike or for unknown reasons. Do 
the inspection per Part 1 and Figure 2 of the Accomplishment 
Instructions of Boeing Alert Service Bulletin 747-53A2489, dated 
November 26, 2002.

    Note 2: For the purposes of this AD, a general visual inspection 
is defined as: ``A visual examination of an interior or exterior 
area, installation, or assembly to detect obvious damage, failure, 
or irregularity. This level of inspection is made from within 
touching distance unless otherwise specified. A mirror may be 
necessary to enhance visual access to all exposed surfaces in the 
inspection area. This level of inspection is made under normally 
available lighting conditions such as daylight, hangar lighting, 
flashlight, or droplight and may require removal or opening of 
access panels or doors. Stands, ladders, or platforms may be 
required to gain proximity to the area being checked.''

Follow-on Inspections

    (b) Except as provided by paragraph (c) of this AD, for any 
repair doubler subject to the requirements of paragraph (a) of this 
AD: Remove the repair doubler and do the inspections/assessment 
(includes external detailed, external visual, and external high 
frequency eddy current (HFEC) inspections) of the fuselage skin for 
damage (cracking or scratches) per Part 2 and Figure 3 of the 
Accomplishment Instructions of Boeing Alert Service Bulletin 747-
53A2489, dated November 26, 2002. Do the inspections at the 
applicable time specified in paragraph (b)(1) or (b)(2) of this AD. 
If any crack or scratch is found, before further flight, do the 
corrective actions specified in paragraph (f) of this AD.

    Note 3: For the purposes of this AD, a detailed inspection is 
defined as: ``An intensive visual examination of a specific 
structural area, system, installation, or assembly to detect damage, 
failure, or irregularity. Available lighting is normally 
supplemented with a direct source of good lighting at intensity 
deemed appropriate by the inspector. Inspection aids such as mirror, 
magnifying lenses, etc., may be used. Surface cleaning and elaborate 
access procedures may be required.''

    (1) If the date of installation of the repair doubler is 
unknown, or 10,000 or more flight cycles have accumulated since the 
date of installation of the repair doubler, do the inspections 
before further flight.
    (2) If less than 10,000 flight cycles have accumulated since the 
date of installation of the repair doubler, do the inspections 
within 10,000 flight cycles after the date of installation of the 
repair doubler.
    (c) For any repair doubler that meets either of the conditions 
specified in paragraphs (c)(1) and (c)(2) of this AD: No action is 
required by this AD for that doubler only.
    (1) The repair doubler is common to the S-46 lap splice and does 
not extend inboard more than 4 inches from the center line.
    (2) A skin assessment was done before installing the repair 
doubler per Figure 6 of Boeing Alert Service Bulletin 747-53A2489, 
dated November 26, 2002.

Optional Repetitive Inspections

    (d) For airplanes that meet the conditions specified in 
paragraph (d)(1) or (d)(2) of this AD, as alternative to the 
inspections required by paragraph (b) of this AD: Do the applicable 
inspections required by either paragraph (d)(1) or (d)(2) of this AD 
per Boeing Alert Service Bulletin 747-53A2489, dated November 26, 
2002; at the applicable time specified in paragraph (b)(1) or (b)(2) 
of this AD.
    (1) If the edge of the doubler does not end on a stringer center 
line: Do an internal mid-frequency eddy current (MFEC) inspection of 
the fuselage skin for cracking (if the edge of the doubler ends on a 
stringer center line it is not possible to do the MFEC inspection) 
per Part 3 and Figure 4 of the Accomplishment Instructions of the 
service bulletin. If no crack is found, before further flight, do an 
external detailed inspection for scratches per Part 3 and Figure 4, 
of the Accomplishment Instructions of the service bulletin. If any 
scratch is found, before further flight, do an external HFEC 
inspection of the scratched area for cracking. If no scratch is 
found during the external detailed inspection or if no crack is 
found during the external HFEC inspection; repeat the MFEC 
inspection at least every 250 flight cycles.
    (2) If the doubler is 20 inches in length or less, do an 
external detailed inspection of the fuselage skin for damage 
(cracking or scratches) per Part 4 and Figure 5 of the 
Accomplishment Instructions of the service bulletin. If any scratch 
is found, before further flight, do an external HFEC inspection of 
the scratched area for cracking. If no scratch is found during the 
external detailed inspection or if no crack is found during the 
external HFEC inspection, repeat the external detailed inspection 
per paragraph (d)(2)(i) or (d)(2)(ii) of this AD, as applicable.
    (i) If the doubler is 8-15 inches in length, repeat the 
inspection at least every 200 flight cycles.
    (ii) If the doubler is 15-20 inches in length, repeat the 
inspection at least every 50 flight cycles.
    (e) If, during any inspection required by paragraph (d)(1) or 
(d)(2) of this AD, any scratch is found, but no crack: Within 1,000 
flight cycles or 18 months after doing the inspection required by 
paragraph (a) of this AD, whichever is first, do the inspections 
required by paragraph (b) of this AD. Accomplishment of this 
paragraph ends the repetitive inspections required by paragraph 
(d)(1) or (d)(2) of this AD, as applicable.

Corrective Actions

    (f) If any crack is found during any inspection required by this 
AD, or if any scratch is found during any inspection required by 
paragraph (b) of this AD: Before further flight, repair per the 
Accomplishment Instructions of Boeing Alert Service Bulletin 747-
53A2489, dated November 26, 2002. Where the service bulletin 
specifies to contact Boeing for appropriate action: Before further 
flight, repair per a method approved by the Manager, Seattle 
Aircraft Certification Office (ACO), FAA; or per data meeting the 
type certification basis of the airplane approved by a Boeing 
Company Designated Engineering Representative who has been 
authorized by the Manager, Seattle ACO, to make such findings. For a 
repair method to be approved, the approval must specifically 
reference this AD.

Adjustments to Compliance Time: Cabin Differential Pressure

    (g) For the purposes of calculating the compliance threshold and 
repetitive interval for the actions required by this AD: The number 
of flight cycles in which cabin differential pressure is at 2.0 
pounds per square inch (psi) or less need not be counted when 
determining the number of flight cycles that have occurred on the 
airplane, provided that flight cycles with momentary spikes in cabin 
differential pressure above 2.0 psi are included as full pressure 
cycles. For this provision to apply, all cabin pressure records must 
be maintained for each airplane: No fleet-averaging of cabin 
pressure is allowed.

Reporting Requirement

    (h) Within 30 days after doing the initial inspections required 
by paragraphs (b) and (d) of this AD: Submit a report of inspection 
findings of cracking or scratches of the fuselage skin to the 
Manager, Seattle Aircraft Certification Office (ACO), FAA, 1601 Lind 
Avenue, SW., Renton, Washington 98055-4056; fax (425) 227-1181. The 
report must include the inspection results (airplane line number, 
size and location of damage, and type of discrepancy found). 
Information collection requirements contained in this AD have been 
approved by the Office of Management and Budget (OMB) under the 
provisions of the Paperwork Reduction Act of

[[Page 5808]]

1980 (44 U.S.C. 3501 et seq.) and have been assigned OMB Control 
Number 2120-0056.

Alternative Methods of Compliance

    (i) An alternative method of compliance or adjustment of the 
compliance time that provides an acceptable level of safety may be 
used if approved by the Manager, Seattle ACO. Operators shall submit 
their requests through an appropriate FAA Principal Maintenance 
Inspector, who may add comments and then send it to the Manager, 
Seattle ACO.

    Note 4: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.

Special Flight Permits

    (j) Special flight permits may be issued in accordance with 
sections 21.197 and 21.199 of the Federal Aviation Regulations (14 
CFR 21.197 and 21.199) to operate the airplane to a location where 
the requirements of this AD can be accomplished.

Incorporation by Reference

    (k) Unless otherwise specified in this AD: The actions shall be 
done in accordance with Boeing Alert Service Bulletin 747-53A2489, 
dated November 26, 2002. This incorporation by reference was 
approved by the Director of the Federal Register in accordance with 
5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from 
Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 
98124-2207. Copies may be inspected at the FAA, Transport Airplane 
Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the 
Office of the Federal Register, 800 North Capitol Street, NW., suite 
700, Washington, DC.

Effective Date

    (l) This amendment becomes effective on February 20, 2003.

    Issued in Renton, Washington, on January 24, 2003.
Ali Bahrami,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 03-2210 Filed 2-4-03; 8:45 am]
BILLING CODE 4910-13-P