[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]
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