[Federal Register Volume 64, Number 6 (Monday, January 11, 1999)]
[Proposed Rules]
[Pages 1549-1552]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-481]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 98-NM-11-AD]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 737 Series Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: This document proposes the adoption of a new airworthiness
directive (AD) that is applicable to certain Boeing Model 737 series
airplanes. This proposal would require inspections of certain bonded
skin panel assemblies to detect delamination of the skin doublers (tear
straps) from the skin panels; and follow-on corrective actions, if
necessary. This proposal is prompted by reports indicating that certain
skin doublers were delaminated from their skin panels due to improper
processing of certain skin panels. The actions specified by the
proposed AD are intended to detect and correct such delamination, which
could result in fatigue cracks in the skin doublers and skin panels,
and consequent rapid decompression of the airplane.
DATES: Comments must be received by February 25, 1999.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-114,
Attention: Rules Docket No. 98-NM-11-AD, 1601 Lind Avenue, SW., Renton,
Washington 98055-4056. Comments may be inspected at this location
between 9:00 a.m. and 3:00 p.m., Monday through Friday, except Federal
holidays.
The service information referenced in the proposed rule 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.
FOR FURTHER INFORMATION CONTACT: Rick Kawaguchi, Aerospace Engineer,
Airframe Branch, ANM-120S, FAA, Transport Airplane Directorate, Seattle
Aircraft Certification Office, 1601 Lind Avenue, SW., Renton,
Washington 98055-4056; telephone (425) 227-1153; fax (425) 227-1181.
SUPPLEMENTARY INFORMATION:
Comments Invited
Interested persons are invited to participate in the making of the
proposed 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 above. All
communications received on or before the closing date for comments,
specified above, will be considered before taking action on the
proposed rule. The proposals contained in this notice may be changed in
light of the comments received.
Comments are specifically invited on the overall regulatory,
economic, environmental, and energy aspects of the proposed 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 summarizing each FAA-public contact concerned with
the substance of this proposal will be filed in the Rules Docket.
Commenters wishing the FAA to acknowledge receipt of their comments
submitted in response to this notice must submit a self-addressed,
stamped postcard on which the following statement is made: ``Comments
to Docket Number 98-NM-11-AD.'' The postcard will be date stamped and
returned to the commenter.
Availability of NPRMs
Any person may obtain a copy of this NPRM by submitting a request
to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules
Docket No. 98-NM-11-AD, 1601 Lind Avenue, SW., Renton, Washington
98055-4056.
Discussion
The FAA has received reports indicating that skin doublers (tear
straps) were found delaminated from their skin panels on certain Boeing
Model 737 series airplanes. These airplanes had accumulated as few as
10,200 total flight cycles. The subject skin doublers and skin panels
are installed above stringer S-26 from body station (BS) 259 to BS 1016
on both sides of the airplane. The cause of such delamination in all
incidents has been attributed to improper processing during the
phosphoric anodize application of the skin panels. This condition, if
not detected and corrected, could result in fatigue cracks in the skin
doublers and skin panels, and consequent rapid decompression of the
airplane.
Explanation of Relevant Service Information
The FAA has reviewed and approved Boeing Service Bulletin 737-53-
1179, dated June 22, 1995, as revised by Notice of Status Change (NSC)
737-53-1179 NSC 1, dated August 17, 1995, which describes procedures
for performing a one-time internal inspection (terminating inspection)
of the bonded skin panel assemblies to detect delamination of the skin
doublers from the skin panels; and follow-on corrective actions, if
necessary.
The above inspection includes an internal close visual inspection
(Figure 3 of the service bulletin), an internal close visual inspection
while trying to separate the skin doublers from the skin panels (Figure
3 of the service bulletin), and an ultrasonic inspection (Figure 4 of
the service bulletin). The service bulletin recommends that operators
perform these inspections on bonded skin panel assemblies, which are
composed of skin doublers (tear straps) that are bonded to skin panels
located above stringer S-26 from BS 259 to BS 1016 on both sides of the
airplane. In lieu of accomplishing the internal close visual
inspections of bonded skin panel assemblies (Figure 3 of the service
bulletin), the service bulletin describes procedures for performing an
internal or external ultrasonic inspection to detect delamination.
The follow-on corrective actions include internal close visual, low
frequency eddy current, and high frequency eddy current inspections;
and repair, if necessary. The service bulletin recommends that
operators perform such inspections to detect corrosion and cracks that
may have resulted from any skin doubler delaminating from its skin
panel.
The service bulletin also describes procedures for performing
repetitive external visual inspections (interim inspection) to detect
cracks in skin panels; and repair, if necessary. This service bulletin
recommends that operators perform the external visual inspections until
accomplishment of the one-time internal inspection described
previously.
Boeing has also issued NSC 737-53-1179 NSC 1, dated August 17,
1995. This NSC contains no new technical information but corrects two
typographical errors and adds a general note.
[[Page 1550]]
Accomplishment of the actions specified in the service bulletin and
the NSC are intended to adequately address the identified unsafe
condition.
Explanation of Requirements of Proposed Rule
Since an unsafe condition has been identified that is likely to
exist or develop on other products of this same type design, the
proposed AD would require accomplishment of the actions specified in
the service bulletin and the NSC described previously, except as
discussed below.
Differences Between Proposed Rule and Service Bulletin
Operators should note that, although the service bulletin
recommends accomplishing a one-time internal inspection (terminating
inspection), as described previously, prior to the accumulation of
40,000 total flight cycles or within 20,000 flight cycles after the
release of the service bulletin, whichever occurs later, the FAA has
determined that such a compliance time would not address the identified
unsafe condition in a timely manner. As described previously, operators
have found doublers delaminated from skin panels on certain Boeing
Model 737 series airplanes that had accumulated as few as 10,200 total
flight cycles. The FAA has determined that to have a high probability
of detecting cracking before it reaches a critical length, the
inspections described previously must be accomplished prior to the
accumulation of 20,000 total flight cycles. In developing an
appropriate compliance time for this proposed AD, the FAA considered
not only the manufacturer's recommendation, but the degree of urgency
associated with addressing the subject unsafe condition, the average
utilization of the affected fleet, and the time necessary to perform
the one-time inspection (136 work hours). In light of all of these
factors, the FAA finds that a proposed compliance time of 20,000 total
flight cycles, or 4,500 flight cycles or 18 months after the effective
date of this AD, whichever occurs later, for initiating the proposed
actions to be warranted. The FAA has determined that the proposed
compliance time represents an appropriate interval of time allowable
for affected airplanes to continue to operate without compromising
safety.
For those operators that elect to perform repetitive external
visual inspections (i.e., the interim inspection), the service bulletin
recommends accomplishing the one-time inspections within 20,000 flight
cycles (after the release of the service bulletin). For the same
reasons stated above, the FAA has determined that such a compliance
time would not address the identified unsafe condition in a timely
manner. Therefore, the FAA finds that a proposed compliance time of
15,000 flight cycles or 60 months after the effective date of this
proposed AD, whichever occurs first, for initiating the proposed
actions [i.e., the one-time (terminating) inspection] to be warranted.
The FAA has determined that the proposed compliance time represents an
appropriate interval of time allowable for affected airplanes to
continue to operate without compromising safety.
Operators also should note that the service bulletin does not
specify that the one-time inspection be accomplished after airplanes
accumulate 4,500 flight cycles on certain bonded skin panel assemblies.
Service history indicates that the bonded skin panel assemblies on the
affected airplanes need to be subjected to a minimal amount of loading
and environment before disbonding becomes detectable. For this reason,
the FAA finds a 4,500 flight cycle interval to be an appropriate
interval of time for ensuring that the operators are able to detect
delamination of the skin doublers from the skin panels. Therefore, the
proposed AD requires that the one-time inspection be performed after
the affected airplanes accumulate 4,500 total flight cycles or after
the affected airplanes accumulate 4,500 flight cycles after the date of
installation of any new or serviceable bonded skin panel assembly.
Although the effectivity listing of the service bulletin includes
airplanes having line numbers 611 through 2725 inclusive, the
applicability of this proposed AD includes airplanes having line
numbers 1 through 3072 inclusive. The service bulletin does not specify
that operators perform an inspection of any new or serviceable bonded
skin panel assembly that was installed prior to October 1, 1997, on any
airplane having line numbers 1 through 3072 inclusive. The FAA has
determined that the identified unsafe condition could exist or develop
on those airplanes having such replacement bonded skin panel
assemblies. In light of this, the FAA finds that it is necessary that
the applicability of this proposed AD include Boeing Model 737 series
airplanes on which the bonded skin panel assemblies were replaced with
any new or serviceable bonded skin panel assemblies prior to October 1,
1997. Therefore, the applicability of this proposed AD includes line
numbers 1 through 3072 inclusive.
Operators should note that, although the service bulletin specifies
that the manufacturer may be contacted for disposition of certain
repair conditions, this proposal 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 Manager,
Seattle Aircraft Certification Office, to make such findings.
Additionally, the service bulletin specifies that certain actions
may be accomplished in accordance with ``an equivalent'' procedure.
However, this proposed AD requires that those actions be accomplished
in accordance with the procedures specified in Part 6, Subject 51-00-
00, Figure 4, of the 737 Nondestructive Test Manual. An ``equivalent''
procedure may be used only if approved as an alternative method of
compliance in accordance with the provisions of paragraph (j) of the
proposed AD.
Cost Impact
There are approximately 2,083 airplanes of the affected design in
the worldwide fleet. The FAA estimates that 863 airplanes of U.S.
registry would be affected by this proposed AD.
It would take approximately 136 work hours per airplane to
accomplish the proposed terminating inspection, at an average labor
rate of $60 per work hour. Based on these figures, the cost impact of
the terminating inspection proposed by this AD on U.S. operators is
estimated to be $7,042,080, or $8,160 per airplane.
It would take approximately 32 work hours per airplane to
accomplish the proposed interim inspection, at an average labor rate of
$60 per work hour. Based on these figures, the cost impact of the
interim inspection proposed by this AD on U.S. operators is estimated
to be $1,656,960, or $1,920 per airplane, per inspection cycle.
The cost impact figures discussed above are based on assumptions
that no operator has yet accomplished any of the proposed requirements
of this AD action, and that no operator would accomplish those actions
in the future if this AD were not adopted.
Regulatory Impact
The regulations proposed herein would 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
[[Page 1551]]
various levels of government. Therefore, in accordance with Executive
Order 12612, it is determined that this proposal would not have
sufficient federalism implications to warrant the preparation of a
Federalism Assessment.
For the reasons discussed above, I certify that this proposed
regulation (1) is not a ``significant regulatory action'' under
Executive Order 12866; (2) is not a ``significant rule'' under the DOT
Regulatory Policies and Procedures (44 FR 11034, February 26, 1979);
and (3) if promulgated, 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. A copy of the draft
regulatory evaluation prepared for this action is contained in the
Rules Docket. A copy of it may be obtained by contacting the Rules
Docket at the location provided under the caption ``ADDRESSES.''
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Safety.
The Proposed Amendment
Accordingly, pursuant to the authority delegated to me by the
Administrator, the Federal Aviation Administration proposes to amend
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:
Boeing: Docket 98-NM-11-AD.
Applicability: Model 737-100, -200, -200C, -300, -400, and -500
series airplanes, line numbers 1 through 3072 inclusive, certified
in any category.
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 (j) 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.
Note 2: Where there are differences between this AD and the
referenced service bulletin, the AD prevails.
Compliance: Required as indicated, unless accomplished
previously.
To detect and correct delamination of the skin doublers (tear
straps) from the skin panels, which could result in fatigue cracks
in the skin doublers and the skin panels, and consequent rapid
decompression of the airplane, accomplish the following:
(a) For airplanes having line numbers 611 through 2725
inclusive, on which any bonded skin panel assembly has not been
replaced with any new or serviceable bonded skin panel assembly:
Accomplish the actions required either by paragraph (a)(1) of this
AD, or by both paragraphs (a)(2) and (a)(3) of this AD, in
accordance with Boeing Service Bulletin 737-53-1179, dated June 22,
1995, as revised by Notice of Status Change 737-53-1179 NSC 1, dated
August 17, 1995.
Note 3: For the purposes of this AD, bonded skin panel
assemblies consist of skin doublers (tear straps) that are bonded to
skin panels located above stringer S-26 from body station (BS) 259
to BS 1016 on both sides of the airplane.
Note 4: If the skin panel is solid with no doublers (tear
straps) bonded to it, the inspections required by this AD are not
necessary for that skin panel.
(1) Prior to the accumulation of 20,000 total flight cycles, but
after the accumulation of 4,500 total flight cycles; or within 18
months or 4,500 flight cycles after the effective date of this AD;
whichever occurs latest; perform a one-time internal inspection
(terminating inspection) of the bonded skin panel assemblies to
detect delamination of the skin doublers from the skin panels, in
accordance with Figures 3 and 4 of the service bulletin. In lieu of
accomplishing the inspections specified in Figure 3 of the service
bulletin, operators can perform an internal or external ultrasonic
inspection in accordance with Note 1. of paragraph A. of the
``Terminating Inspection'' Section of the Accomplishment
Instructions of the service bulletin.
Note 5: For the purposes of this AD, the one-time internal
inspection includes an internal close visual inspection (Figure 3),
an internal close visual inspection while trying to separate the
skin doublers from the skin panels (Figure 3), and an ultrasonic
inspection (Figure 4).
(2) Within 4,500 flight cycles or 18 months after the effective
date of this AD, whichever occurs later, perform an external visual
inspection of the bonded skin panel assemblies to detect cracks in
the skin panels, in accordance with paragraph A. of the ``Interim
Inspection'' Section of the Accomplishment Instructions of the
service bulletin. Repeat the external visual inspection thereafter
at intervals not to exceed 4,500 flight cycles, until accomplishment
of the requirements specified in paragraph (a)(3) of this AD.
(3) Within 15,000 flight cycles or 60 months after the effective
date of this AD, whichever occurs first, accomplish the one-time
internal inspection required by paragraph (a)(1) of this AD.
Accomplishment of this action constitutes terminating action for the
repetitive inspections required by paragraph (a)(2) of this AD.
(b) For airplanes having line numbers 611 through 2725
inclusive, on which any bonded skin panel assembly was replaced with
any new or serviceable bonded skin panel assembly prior to October
1, 1997: Accomplish the actions required by both paragraphs (b)(1)
and (b)(2) of this AD, or by both paragraphs (b)(3) and (b)(4) of
this AD, in accordance with Boeing Service Bulletin 737-53-1179,
dated June 22, 1995, as revised by Notice of Status Change 737-53-
1179 NSC 1, dated August 17, 1995.
(1) Prior to the accumulation of 20,000 total flight cycles, but
after the accumulation of 4,500 total flight cycles; or within 4,500
flight cycles or 18 months after the effective date of this AD;
whichever occurs latest; perform a one-time internal inspection
(terminating inspection) of the bonded skin panel assemblies that
have not been replaced to detect delamination of the skin doublers
from the skin panels, in accordance with Figures 3 and 4 of the
service bulletin. In lieu of accomplishing the inspections specified
in Figure 3 of the service bulletin, operators can perform an
internal or external ultrasonic inspection in accordance with Note
1. of paragraph A. of the ``Terminating Inspection'' Section of the
Accomplishment Instructions of the service bulletin.
(2) Prior to the accumulation of 20,000 flight cycles after the
date of replacement of the skin panel assembly, but not prior to the
accumulation of 4,500 flight cycles after the date of such
replacement; or within 4,500 flight cycles or 18 months after the
effective date of this AD; whichever occurs latest; perform a one-
time internal inspection (terminating inspection) of the bonded skin
panel assemblies that have been replaced to detect delamination of
the skin doublers from the skin panels, in accordance with Figures 3
and 4 of the service bulletin. In lieu of accomplishing the
inspections identified in Figure 3 of the service bulletin,
operators can perform an internal or external ultrasonic inspection
in accordance with Note 1. of paragraph A. of the ``Terminating
Inspection'' Section of the Accomplishment Instructions of the
service bulletin.
(3) Within 4,500 flight cycles or 18 months after the effective
date of this AD, whichever occurs later, perform an external visual
inspection of the skin panel assemblies that have and have not been
replaced to detect cracks in the skin panels, in accordance with
paragraph A. of the ``Interim Inspection'' Section of the
Accomplishment Instructions of the service bulletin. Repeat the
external visual inspection thereafter at intervals not to exceed
4,500 flight cycles, until accomplishment of the requirements
specified in paragraph (b)(4) of this AD.
(4) Within 15,000 flight cycles or 60 months after the effective
date of this AD, whichever occurs first, accomplish the one-time
internal inspection required by both paragraphs (b)(1) and (b)(2) of
this AD. Accomplishment of this action constitutes terminating
action for the repetitive inspections required by paragraph (b)(3)
of this AD.
(c) For airplanes having line numbers 611 through 2725
inclusive, on which any
[[Page 1552]]
bonded skin panel assembly was replaced with any new or serviceable
bonded skin panel assembly after September 30, 1997: Accomplish the
actions required either by paragraph (c)(1) or by both paragraphs
(c)(2) and (c)(3) of this AD, in accordance with Boeing Service
Bulletin 737-53-1179, dated June 22, 1995, as revised by Notice of
Status Change 737-53-1179 NSC 1, dated August 17, 1995.
(1) Prior to the accumulation of 20,000 total flight cycles, but
not prior to the accumulation of 4,500 total flight cycles; or
within 4,500 flight cycles or 18 months after the effective date of
this AD; whichever occurs latest; perform a one-time internal
inspection (terminating inspection) of the bonded skin panel
assemblies that have not been replaced to detect delamination of the
skin doublers from the skin panels, in accordance with Figures 3 and
4 of the service bulletin. In lieu of accomplishing the inspections
identified in Figure 3 of the service bulletin, operators can
perform an internal or external ultrasonic inspection in accordance
with NOTE 1. of paragraph A. of the ``Terminating Inspection''
Section of the Accomplishment Instructions of the service bulletin.
(2) Within 4,500 flight cycles or 18 months after the effective
date of this AD, whichever occurs later, perform an external visual
inspection of the bonded skin panel assemblies that have not been
replaced to detect cracks in the skin panels, in accordance with
paragraph A. of the ``Interim Inspection'' Section of the
Accomplishment Instructions of the service bulletin. Repeat the
external visual inspection thereafter at intervals not to exceed
4,500 flight cycles, until accomplishment of the requirements
specified in paragraph (c)(3) of this AD.
(3) Within 15,000 flight cycles or 60 months after the effective
date of this AD, whichever occurs first, accomplish the one-time
internal inspection required by paragraph (c)(1) of this AD.
Accomplishment of this action constitutes terminating action for the
repetitive inspections required by paragraph (c)(2) of this AD.
(d) For airplanes having line numbers 1 through 610 inclusive,
and 2726 through 3072 inclusive, on which any bonded skin panel
assembly was replaced with any new or serviceable bonded skin panel
assembly prior to October 1, 1997: Accomplish the actions required
either by paragraph (d)(1) or by both paragraphs (d)(2) and (d)(3)
of this AD, in accordance with Boeing Service Bulletin 737-53-1179,
dated June 22, 1995, as revised by Notice of Status Change 737-53-
1179 NSC 1, dated August 17, 1995.
(1) Prior to the accumulation of 20,000 flight cycles after the
date of replacement of the skin panel assembly, but not prior to the
accumulation of 4,500 flight cycles after the date of such
replacement; or within 4,500 flight cycles or 18 months after the
effective date of this AD; whichever occurs latest; perform a one-
time internal inspection (terminating inspection) of the bonded skin
panel assemblies that have been replaced to detect delamination of
the skin doublers from the skin panels, in accordance with Figures 3
and 4 of the service bulletin. In lieu of accomplishing the
inspections specified in Figure 3 of the service bulletin, operators
can perform an internal or external ultrasonic inspection in
accordance with NOTE 1. of paragraph A. of the ``Terminating
Inspection'' Section of the Accomplishment Instructions of the
service bulletin.
(2) Within 4,500 flight cycles or 18 months after the effective
date of this AD, whichever occurs later, perform an external visual
inspection of the bonded skin panel assemblies that have been
replaced to detect cracks in the skin panels, in accordance with
paragraph A. of the Interim Inspection of the Accomplishment
Instructions of the service bulletin. Repeat the external visual
inspection thereafter at intervals not to exceed 4,500 flight
cycles, until accomplishment of the requirements specified in
paragraph (d)(3) of this AD.
(3) Within 15,000 flight cycles or 60 months after the effective
date of this AD, whichever occurs first, accomplish the one-time
internal inspection required by paragraph (d)(1) of this AD.
Accomplishment of this action constitutes terminating action for the
repetitive inspections required by paragraph (d)(2) of this AD.
(e) If any crack is detected during any inspection required by
paragraph (a)(2), (b)(3), (c)(2), or (d)(2) of this AD, prior to
further flight, accomplish the actions required by paragraph (b)(1)
and (b)(2) of this AD, as applicable.
(1) If any crack is detected in any skin panel that is above
stringer S-10 or between stringers S-14 and S-26, repair in
accordance with Boeing Service Bulletin 737-53-1179, dated June 22,
1995, as revised by Notice of Status Change 737-53-1179 NSC 1, dated
August 17, 1995.
(2) If any crack is detected in any skin panel that is between
stringers S-10 and S-14 (window belt), repair in accordance with a
method approved by the Manager, Seattle Aircraft Certification
Office (ACO), FAA, Transport Airplane Directorate; 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 Manager, Seattle ACO, to make such
findings.
(f) If no delamination is detected during any inspection
required by paragraph (a)(1), (a)(3), (b)(1), (b)(2), (b)(4),
(c)(1), (c)(3), (d)(1), or (d)(3) of this AD, no further action is
required by this AD.
(g) If any delamination is detected during any inspection
required by paragraph (a)(1), (a)(3), (b)(1), (b)(2), (b)(4),
(c)(1), (c)(3), (d)(1), or (d)(3) of this AD, prior to further
flight, accomplish the actions required by either paragraph (g)(1)
or (g)(2) of this AD, as applicable.
(1) If the delaminated area is less than 3 square inches and is
not at the edge of a skin doubler or under a fastener head, no
further action is required by this AD for that delaminated area.
(2) If the delaminated area is equal to or greater than 3 square
inches or is located at the edge of a skin doubler or under a
fastener head, prior to further flight, accomplish the follow-on
corrective actions in accordance with the ``Terminating Inspection''
Section of the Accomplishment Instructions of Boeing Service
Bulletin 737-53-1179, dated June 22, 1995, as revised by Notice of
Status Change 737-53-1179 NSC 1, dated August 17, 1995, except as
provided by paragraphs (h) and (i) of this AD.
(h) Where Boeing Service Bulletin 737-53-1179, dated June 22,
1995, as revised by Notice of Status Change 737-53-1179 NSC 1, dated
August 17, 1995, specifies that the actions required by this AD may
be accomplished in accordance with an ``equivalent'' procedure, the
actions must be accomplished in accordance with the chapter of the
Boeing 737 Nondestructive Test Manual specified in the service
bulletin.
(i) Where Boeing Service Bulletin 737-53-1179, dated June 22,
1995, as revised by Notice of Status Change 737-53-1179 NSC 1, dated
August 17, 1995, specifies that the repair of a delaminated lap
splice is to be accomplished in accordance with instructions
received from Boeing, this AD requires that the repair be
accomplished in accordance with a method approved by the Manager,
Seattle ACO; 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
Manager, Seattle ACO, to make such findings.
(j) 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 6: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Seattle ACO.
(k) 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.
Issued in Renton, Washington, on December 31, 1998.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 99-481 Filed 1-8-99; 8:45 am]
BILLING CODE 4910-13-U
