[Federal Register Volume 61, Number 219 (Tuesday, November 12, 1996)]
[Rules and Regulations]
[Pages 57994-57998]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-28169]
-----------------------------------------------------------------------
DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 96-NM-251-AD; Amendment 39-9807; AD 96-23-02]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 747 Series Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule; request for comments.
-----------------------------------------------------------------------
SUMMARY: This amendment adopts a new airworthiness directive (AD) that
is applicable to certain Boeing Model 747 series airplanes. This action
requires inspections to detect disbonding, corrosion, and cracking at
the longitudinal rows of fasteners in the bonded skin panels in section
41 of the fuselage, and repair, if necessary. This amendment is
prompted by a report of skin cracking due to disbonding of the internal
doubler of the cracked skin panels. The actions specified in this AD
are intended to prevent rapid decompression of the airplane due to
disbonding and subsequent cracking of the skin panels.
DATES: Effective November 27, 1996.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of November 27, 1996.
Comments for inclusion in the Rules Docket must be received on or
before January 13, 1997.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-103,
Attention: Rules Docket No. 96-NM-251-AD, 1601 Lind Avenue, SW.,
Renton, Washington 98055-4056.
The service information referenced in this AD may be obtained from
Boeing Commercial Airplane Group, P.O. 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: Bob Breneman, Aerospace Engineer,
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office,
1601 Lind Avenue, SW., Renton, Washington; telephone (206) 227-2776;
fax (206) 227-1181.
SUPPLEMENTARY INFORMATION: Recently, the FAA received a report
indicating that skin cracking was found on a Boeing Model 747-200
series airplane that had accumulated 14,486 total flight cycles.
Multiple one-inch skin cracks were found through four adjacent fastener
holes along the number 2 doorstop intercostal between body station (BS)
488 and BS 500. The FAA received another report indicating that skin
cracking was found in the same location on a Model 747-200 series
airplane that had accumulated 13,517 total flight cycles. This cracking
measured approximately 17 inches in length.
Results of subsequent inspections of both airplanes revealed
extensive disbonding of the internal doubler of the cracked skin
panels, as well as disbonding at several stringer locations from BS 340
to BS 520 between stringer (S) 6 and S-14. The cause of this disbonding
has been attributed to improper processing during the phosphoric acid
anodize (PAA) phase of manufacture of the skin panels.
Disbonding of the internal skin doublers could result in increased
operational stress on the fuselage skin, and could lead to multiple-
site skin cracking. This condition, if not corrected, could result in
rapid decompression of the airplane.
[[Page 57995]]
Explanation of Relevant Service Information
The FAA has reviewed and approved Boeing Alert Service Bulletin
747-53A2409, dated September 26, 1996, which describes procedures for
inspections to detect disbonding, corrosion, and cracking of the
longitudinal rows of fasteners in the bonded skin panels in section 41
of the fuselage, and repair, if necessary. The alert service bulletin
identifies four affected skin areas:
Area 1: The flat skin panel aft of the cockpit windows
from body station (BS) 340 to BS 520 between S-6 and S-14.
Area 2: The flat skin panels below the cockpit windows.
Area 3: The large-radius skin panels in the main deck area
(excluding Area 4).
Area 4: The section of the large-radius skin panel aft of
door 1 from BS 488 to BS 500 between S-16 and S-26.
The alert service bulletin also specifies four methods of
inspection:
Method 1: One-time external ultrasonic inspections (for
Area 1 only) of the skin for disbonded doublers; and an external
inspection of the skin for cracks, and repair, if necessary;
Method 2: One-time internal visual inspections of the skin
for disbonded doublers, corrosion, or cracks; and repair, or an
external inspection of the skin for cracks, if necessary;
Method 3: Repetitive external close visual inspections of
the skin for cracks, and repair, if necessary; and
Method 4: Repetitive external high frequency eddy current
(HFEC) inspections of the skin for cracks, and repair, if necessary.
Explanation of the Requirements of the Rule
Since an unsafe condition has been identified that is likely to
exist or develop on other Boeing Model 747 series airplanes of the same
type design, this AD is being issued to prevent rapid decompression of
the airplane due to disbonding and subsequent cracking of the skin
panels. This AD requires inspections to detect disbonding, corrosion,
and cracking at the longitudinal rows of fasteners in the bonded skin
panels in section 41 of the fuselage, and repair, if necessary. Certain
repairs are required to be accomplished in accordance with a method
approved by the FAA. Other actions are required to be accomplished in
accordance with the alert service bulletin described previously.
This AD also requires that operators submit a report to the FAA of
any findings of disbonding detected during the inspections required by
this AD.
Differences Between Alert Service Bulletin and This AD
While the alert service bulletin describes procedures for
inspections of four particular areas of the airplane, this AD requires
inspections of only two of those areas. The FAA is considering further
rulemaking to require inspections of the other two areas that are not
addressed in this AD; however, the proposed compliance time for
accomplishment of those inspections is sufficiently long so that prior
notice and time for public comment will be practicable.
Additionally, the alert service bulletin specifies that, based on
continued mixed operation at lower cabin differential pressures, the
thresholds and intervals specified in the alert service bulletin can be
multiplied by a 1.2 adjustment factor for Model 747SR and 747-400
series airplanes (domestic only). The FAA finds that insufficient data
exist to support such an adjustment to flight cycles. In fact, data are
available which indicate that the use of a 1.2 adjustment factor
provides inaccurate data and unjustified relief for inspection
intervals. Consequently, this AD does not allow for such an adjustment
factor.
Further, the alert service bulletin indicates that if any cracking
is found that is outside specified limits, operators should contact the
manufacturer for repair data. However, this AD requires that such
cracking be repaired in accordance with a method approved by the FAA.
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.
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 96-NM-251-AD''. The postcard will be date stamped and
returned to the commenter.
Regulatory Impact
The regulations adopted herein will not have substantial direct
effects 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, in
accordance with Executive Order 12612, it is determined that this final
rule does not have sufficient federalism implications to warrant the
preparation of a Federalism Assessment.
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.
[[Page 57996]]
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:
96-23-02 Boeing: Amendment 39-9807. Docket 96-NM-251-AD.
Applicability: Model 747 series airplanes; line numbers 1
through 200 inclusive on which the skin panel replacement specified
in Boeing Service Bulletin 747-53A2321 has been accomplished; line
numbers 201 through 430 inclusive that have been modified by Boeing
to a Stretched Upper Deck (SUD) configuration; and line numbers 431
through 1075 inclusive; certificated in any category.
Note 1: This AD applies to each airplane identified in the
preceding applicability provision, regardless of whether it has been
otherwise 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 (u) 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 prevent rapid decompression of the airplane due to disbonding
and subsequent cracking of the skin panels, accomplish the
following:
Disallowance of Adjustment Factor
(a) For Model 747SR and 747-400 series airplanes operating at a
cabin differential pressure lower than 8.9 pounds per square inch
(psi): An adjustment factor of 1.2 shall not be used as a multiplier
for thresholds and intervals specified in Boeing Alert Service
Bulletin 747-53A2409, dated September 26, 1996.
Initial Inspection of Area 1: Group 1 Airplanes
(b) For airplanes identified as Group 1 in Boeing Alert Service
Bulletin 747-53A2409, dated September 26, 1996, on which the skin
panel replacement specified in Boeing Alert Service Bulletin 747-
53A2321 has been accomplished: Perform an inspection to detect
disbonding, corrosion, and/or cracking of the skin at the location
specified as Area 1 in Table 1 of the Accomplishment Instructions of
Boeing Alert Service Bulletin 747-53A2409, dated September 26, 1996,
using an inspection technique identified as Method 1, 2, 3, or 4 in
paragraph A., Part I, of the Accomplishment Instructions of the
alert service bulletin. Accomplish the inspection at the time
specified in paragraph (b)(1) or (b)(2) of this AD, as applicable.
In any case, any inspection using Method 1 or 2 shall not be
accomplished prior to the accumulation of 2,000 total flight cycles
with cabin differential pressure above 2.0 psi since skin panel
replacement in accordance with Boeing Alert Service Bulletin 747-
53A2321. If inspection Method 1 or 2 is used and no disbonded
doubler is found, no further action is required by this AD.
(1) For airplanes on which zones 1 and 2 of the fuselage have
not been modified in accordance with Boeing Service Bulletin 747-53-
2272: Inspect at the later of the times specified in paragraphs
(b)(1)(i) and (b)(1)(ii) of this AD.
(i) Prior to the accumulation of 8,000 total flight cycles, or
within 150 flight cycles after the effective date of this AD,
whichever occurs later.
(ii) Within 60 days after the effective date of this AD.
(2) For airplanes on which zones 1 and 2 of the fuselage have
been modified in accordance with Boeing Service Bulletin 747-53-
2272: Inspect at the later of the times specified in paragraphs
(b)(2)(i) and (b)(2)(ii) of this AD.
(i) Prior to the accumulation of 10,000 total flight cycles, or
within 150 flight cycles after the effective date of this AD,
whichever occurs later.
(ii) Within 60 days after the effective date of this AD.
On-Condition Repairs and Repetitive Inspections: Group 1 Airplanes
(c) If inspection Method 1 or 2 was used to accomplish the
inspection required by paragraph (b) of this AD, and any disbonded
doubler was found during that inspection: Prior to further flight,
perform external detailed visual inspections (Method 3) or external
HFEC inspections (Method 4) to detect cracking of the fuselage skin
in the areas where the disbonded doubler was found, in accordance
with Boeing Alert Service Bulletin 747-53A2409, dated September 26,
1996.
(1) If inspection Method 3 was used to accomplish the inspection
required by paragraph (c) of this AD, and no cracking was found
during the inspection: Repeat the inspection thereafter at intervals
not to exceed 150 flight cycles for up to 1,000 flight cycles;
thereafter, perform external HFEC inspections (Method 4) at
intervals not to exceed 2,000 flight cycles in accordance with the
alert service bulletin.
(2) If inspection Method 4 was used to accomplish the inspection
required by paragraph (c) of this AD, and no cracking was found
during the inspection: Repeat the inspection thereafter at intervals
not to exceed 2,000 flight cycles in accordance with the alert
service bulletin.
(d) If inspection Method 3 was used to accomplish the inspection
required by paragraph (b) of this AD, and no cracking was found
during the inspection: Repeat the inspection thereafter at intervals
not to exceed 150 flight cycles for up to 1,000 flight cycles;
thereafter, accomplish either paragraph (d)(1) or (d)(2) of this AD
in accordance with Boeing Alert Service Bulletin 747-53A2409, dated
September 26, 1996.
(1) Perform a one-time inspection using Method 1 or 2; or
(2) Perform repetitive inspections using inspection Method 4 at
intervals not to exceed 2,000 flight cycles.
(e) If inspection Method 4 was used to accomplish the inspection
required by paragraph (b) of this AD, and no cracking was found
during the inspection: Repeat the inspection thereafter at intervals
not to exceed 2,000 flight cycles in accordance with Boeing Alert
Service Bulletin 747-53A2409, dated September 26, 1996.
(f) If any cracking is found during any inspection required by
paragraphs (b), (c), (d), or (e) of this AD, and the cracking is
within the limits specified in Boeing Alert Service Bulletin 747-
53A2409, dated September 26, 1996, prior to further flight, repair
in accordance with the alert service bulletin. Following repair,
perform repetitive inspections using inspection Method 4 thereafter
at intervals not to exceed 2,000 flight cycles in accordance with
the alert service bulletin.
(g) If any cracking is found during any inspection required by
paragraphs (b), (c), (d), or (e) of this AD, and the cracking is
outside the limits specified in Boeing Alert Service Bulletin 747-
53A2409, dated September 26, 1996, prior to further flight, repair
in accordance with a method approved by the Manager, Seattle
Aircraft Certification Office (ACO), FAA, Transport Airplane
Directorate.
Initial Inspection of Areas 1 and 4: Groups 2, 3, 6, and 8 Airplanes
(h) For airplanes identified as Group 2, 3, 6, or 8 in Boeing
Alert Service Bulletin 747-53A2409, dated September 26, 1996:
Perform inspections to detect disbonding, corrosion, and/or cracking
of the skin at the locations specified as Areas 1 and 4 in Table 1
of the Accomplishment Instructions of Boeing Alert Service Bulletin
747-53A2409, dated September 26, 1996, using an inspection technique
identified as Method 1, 2, 3, or 4 (for Area 1), or Method 2, 3, or
4 (for Area 4) in paragraph A., Part I, of the Accomplishment
Instructions of the alert service bulletin. Accomplish the
inspection at the time specified in paragraph (h)(1) or (h)(2) of
this AD, as applicable. In any case, any inspection using Method 1
or 2 shall not be accomplished prior to the accumulation of 2,000
total flight cycles with cabin differential pressure above 2.0 psi
since delivery, or since modification to the SUD configuration. If
inspection Method 1 or 2 is used and no disbonded doubler is found,
no further action is required by this AD.
(1) For airplanes on which zones 1, 2, and 3 of the fuselage
have not been modified in accordance with Boeing Service Bulletin
[[Page 57997]]
747-53-2272: Inspect at the later of the times specified in
paragraphs (h)(1)(i) and (h)(1)(ii) of this AD.
(i) Prior to the accumulation of 8,000 total flight cycles, or
within 150 flight cycles after the effective date of this AD,
whichever occurs later.
(ii) Within 60 days after the effective date of this AD.
(2) For airplanes on which zones 1, 2, and 3 of the fuselage
have been modified in accordance with Boeing Service Bulletin 747-
53-2272: Inspect at the later of the times specified in paragraphs
(h)(2)(i) and (h)(2)(ii) of this AD.
(i) Prior to the accumulation of 10,000 total flight cycles, or
within 150 flight cycles after the effective date of this AD,
whichever occurs later.
(ii) Within 60 days after the effective date of this AD.
On-Condition Repairs and Repetitive Inspections: Groups 2, 3, 6, and 8
Airplanes
(i) If inspection Method 1 or 2 was used to accomplish the
inspection required by paragraph (h) of this AD, and any disbonded
doubler was found during that inspection: Prior to further flight,
perform external detailed visual inspections (Method 3) or external
HFEC inspections (Method 4) to detect cracking of the fuselage skin
in the areas where the disbonded doubler was found, in accordance
with Boeing Alert Service Bulletin 747-53A2409, dated September 26,
1996.
(1) If inspection Method 3 was used to accomplish the inspection
required by paragraph (i) of this AD, and no cracking was found
during the inspection: Repeat the inspection thereafter at intervals
not to exceed 150 flight cycles (for Area 1) or 250 flight cycles
(for Area 4), as applicable, for up to 1,000 flight cycles;
thereafter, perform external HFEC inspections (Method 4) at
intervals not to exceed 2,000 flight cycles (for Area 1) or 3,000
flight cycles (for Area 4), as applicable, in accordance with the
alert service bulletin.
(2) If inspection Method 4 was used to accomplish the inspection
required by paragraph (i) of this AD, and no cracking was found
during the inspection: Repeat the inspection thereafter at intervals
not to exceed 2,000 flight cycles (for Area 1) or 3,000 flight
cycles (for Area 4), as applicable, in accordance with the alert
service bulletin.
(j) If inspection Method 3 was used to accomplish the inspection
required by paragraph (h) of this AD, and no cracking was found
during the inspection: Repeat the inspection thereafter at intervals
not to exceed 150 flight cycles (for Area 1) or 250 flight cycles
(for Area 4), as applicable, for up to 1,000 flight cycles;
thereafter, accomplish either paragraph (j)(1) or (j)(2) of this AD
in accordance with Boeing Alert Service Bulletin 747-53A2409, dated
September 26, 1996.
(1) Perform a one-time inspection using Method 1 or 2 (for Area
1), or Method 2 (for Area 4 only); or
(2) Perform repetitive inspections using inspection Method 4 at
intervals not to exceed 2,000 flight cycles (for Area 1) or 3,000
flight cycles (for Area 4), as applicable.
(k) If inspection Method 4 was used to accomplish the inspection
required by paragraph (h) of this AD, and no cracking was found
during the inspection: Repeat the inspection thereafter at intervals
not to exceed 2,000 flight cycles (for Area 1) or 3,000 flight
cycles (for Area 4), as applicable, in accordance with Boeing Alert
Service Bulletin 747-53A2409, dated September 26, 1996.
(l) If any cracking is found during any inspection required by
paragraphs (h), (i), (j), or (k) of this AD, and the cracking is
within the limits specified in Boeing Alert Service Bulletin 747-
53A2409, dated September 26, 1996, prior to further flight, repair
in accordance with the alert service bulletin. Following repair,
perform repetitive inspections using inspection Method 4 thereafter
at intervals not to exceed 2,000 flight cycles (for Area 1) or 3,000
flight cycles (for Area 4), as applicable, in accordance with the
alert service bulletin.
(m) If any cracking is found during any inspection required by
paragraphs (h), (i), (j), or (k) of this AD, and the cracking is
outside the limits specified in Boeing Alert Service Bulletin 747-
53A2409, dated September 26, 1996, prior to further flight, repair
in accordance with a method approved by the Manager, Seattle
Aircraft Certification Office (ACO), FAA, Transport Airplane
Directorate.
Initial Inspection of Areas 1 and 4: Groups 4, 5, 7, 9, and 10
Airplanes
(n) For airplanes identified as Group 4, 5, 7, 9, or 10 in
Boeing Alert Service Bulletin 747-53A2409, dated September 26, 1996:
Perform inspections to detect disbonding, corrosion, and/or cracking
of the skin at the locations specified as Areas 1 and 4 in Table 1
of the Accomplishment Instructions of Boeing Alert Service Bulletin
747-53A2409, dated September 26, 1996, using an inspection technique
identified as Method 1, 2, 3, or 4 (for Area 1) or Method 2, 3, or 4
(for Area 4) in paragraph A., Part I, of the Accomplishment
Instructions of the alert service bulletin. Accomplish the
inspection at the later of the times specified in paragraphs (n)(1)
and (n)(2) of this AD. In any case, any inspection using Method 1 or
2 shall not be accomplished prior to the accumulation of 2,000 total
flight cycles with cabin differential pressure above 2.0 psi since
delivery. If inspection Method 1 or 2 is used and no disbonded
doubler is found, no further action is required by this AD.
(1) Prior to the accumulation of 10,000 total flight cycles, or
within 150 flight cycles after the effective date of this AD,
whichever occurs later.
(2) Within 60 days after the effective date of this AD.
On-Condition Repairs and Repetitive Inspections: Groups 4, 5, 7, 9, and
10 Airplanes
(o) If inspection Method 1 or 2 was used to accomplish the
inspection required by paragraph (n) of this AD, and any disbonded
doubler was found during that inspection: Prior to further flight,
perform external detailed visual inspections (Method 3) or external
HFEC inspections (Method 4) to detect cracking of the fuselage skin
in the areas where the disbonded doubler was found, in accordance
with Boeing Alert Service Bulletin 747-53A2409, dated September 26,
1996.
(1) If inspection Method 3 was used to accomplish the inspection
required by paragraph (o) of this AD, and no cracking was found
during the inspection: Repeat the inspection thereafter at intervals
not to exceed 150 flight cycles (for Area 1) or 250 flight cycles
(for Area 4), as applicable, for up to 1,000 flight cycles;
thereafter, perform external HFEC inspections (Method 4) at
intervals not to exceed 2,000 flight cycles (for Area 1) or 3,000
flight cycles (for Area 4), as applicable, in accordance with the
alert service bulletin.
(2) If inspection Method 4 was used to accomplish the inspection
required by paragraph (o) of this AD, and no cracking was found
during the inspection: Repeat the inspection thereafter at intervals
not to exceed 2,000 flight cycles (for Area 1) or 3,000 flight
cycles (for Area 4), as applicable, in accordance with the alert
service bulletin.
(p) If inspection Method 3 was used to accomplish the inspection
required by paragraph (n) of this AD, and no cracking was found
during the inspection: Repeat the inspection thereafter at intervals
not to exceed 150 flight cycles (for Area 1) or 250 flight cycles
(for Area 4), as applicable, for up to 1,000 flight cycles;
thereafter, accomplish either paragraph (p)(1) or (p)(2) of this AD
in accordance with Boeing Alert Service Bulletin 747-53A2409, dated
September 26, 1996.
(1) Perform a one-time inspection using Method 1 or 2 (for Area
1), or Method 2 (for Area 4 only); or
(2) Perform repetitive inspections using inspection Method 4 at
intervals not to exceed 2,000 flight cycles (for Area 1) or 3,000
flight cycles (for Area 4), as applicable.
(q) If inspection Method 4 was used to accomplish the inspection
required by paragraph (n) of this AD, and no cracking was found
during the inspection: Repeat the inspection thereafter at intervals
not to exceed 2,000 flight cycles (for Area 1) or 3,000 flight
cycles (for Area 4), as applicable, in accordance with Boeing Alert
Service Bulletin 747-53A2409, dated September 26, 1996.
(r) If any cracking is found during any inspection required by
paragraphs (n), (o), (p), or (q) of this AD, and the cracking is
within the limits specified in Boeing Alert Service Bulletin 747-
53A2409, dated September 26, 1996, prior to further flight, repair
in accordance with the alert service bulletin. Following repair,
perform repetitive inspections using inspection Method 4 thereafter
at intervals not to exceed 2,000 flight cycles (for Area 1) or 3,000
flight cycles (for Area 4), as applicable.
(s) If any cracking is found during any inspection required by
paragraphs (n), (o), (p), or (q) of this AD, and the cracking is
outside the limits specified in Boeing Alert Service Bulletin 747-
53A2409, dated September 26, 1996, prior to further flight, repair
in accordance with a method approved by the Manager, Seattle
Aircraft Certification Office (ACO), FAA, Transport Airplane
Directorate.
[[Page 57998]]
(t) Within 10 days after accomplishing any inspection to detect
disbonding required by paragraphs (b), (d)(1), (h), (j)(1), (n), and
(p)(1) this AD, report any findings of disbonding to the Manager,
Seattle Manufacturing Inspection District Office, FAA, Transport
Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington
98055-4056; fax (206) 227-1159. The report shall include the
information specified in paragraphs (t)(1), (t)(2), and (t)(3) of
this AD. Information collection requirements contained in this
regulation have been approved by the Office of Management and Budget
(OMB) under the provisions of the Paperwork Reduction Act of 1980
(44 U.S.C. 3501 et seq.) and have been assigned OMB Control Number
2120-0056.
(1) The line number of the airplane on which disbonding was
found.
(2) The number of disbonded skin panels that were found.
(3) The part number of any disbonded skin panel that is found.
(u) 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 2: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Seattle ACO.
(v) 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.
(w) The actions shall be done in accordance with Boeing Alert
Service Bulletin 747-53A2409, dated September 26, 1996. 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.
(x) This amendment becomes effective on November 27, 1996.
Issued in Renton, Washington, on October 28, 1996.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 96-28169 Filed 11-8-96; 8:45 am]
BILLING CODE 4910-13-U
