[Federal Register Volume 60, Number 12 (Thursday, January 19, 1995)]
[Rules and Regulations]
[Pages 3739-3741]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-1362]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 94-NM-217-AD; Amendment 39-9108; AD 94-26-13]
Airworthiness Directives; Boeing Model 737-300, -400, and -500
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),
applicable to certain Boeing Model 737-300, -400, and -500 series
airplanes. This action requires modification of the leading edge slat
access panel and internal structure at Front Spar Station (FSS)
250.663. This amendment is prompted by reports that fuel leaking from
the fuel line at FSS 250.663 flowed through a drain hole in a slat
access panel and leaked into the turbine exhaust area. The actions
specified in this AD are intended to prevent drainage from such a fuel
leak into the turbine exhaust area, which could cause an external fire
under the wing.
DATES: Effective on February 3, 1995.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of February 3, 1995.
Comments for inclusion in the Rules Docket must be received on or
before March 20, 1995.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-103,
Attention: Rules Docket No. 94-NM-217-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
[[Page 3740]]
the Federal Register, 800 North Capitol Street, NW., suite 700,
Washington, DC.
FOR FURTHER INFORMATION CONTACT: Stephen S. Bray, Aerospace Engineer,
Propulsion Branch, ANM-140S, FAA, Transport Airplane Directorate,
Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton,
Washington 98055-4056; telephone (206) 227-2681; fax (206) 227-1181.
SUPPLEMENTARY INFORMATION: On March 10, 1994, the FAA issued AD 94-06-
11, amendment 39-8858 (59 FR 13444, March 22, 1994), applicable to
certain Boeing Model 737-300, -400, and -500 series airplanes. That AD
requires modification of the leading edge slat access panel and
internal structure at Front Spar Station (FSS) 250.663. That action was
prompted by reports that fuel leaking from the fuel line at FSS 250.663
flowed through a drain hole in a slat access panel and leaked into the
turbine exhaust area. (The strut drain system installed on these
airplanes is designed to divert fuel leakage to a point five feet from
the turbine exhaust area.) One of the incidents caused an external fire
under the wing. Typically, such a fire could occur on the ground after
the engines have been shut down. The resultant fire could spread from
the turbine exhaust area to the strut and, subsequently, could ignite
fuel within the strut. This condition, if not detected and corrected,
could cause an external fire under the wing.
Since issuance of AD 94-06-11, the FAA has determined that the same
unsafe condition addressed in that AD may exist on certain additional
Model 737-300, -400, and -500 series airplanes; therefore, these
additional airplanes also are subject to fuel leakage into the turbine
exhaust area, which could cause an external fire under the wing. AD 94-
06-11 is applicable only to airplanes having line positions 1001
through 1976 inclusive, 1978 through 2183 inclusive, 2185 through 2186
inclusive, and 2188 through 2193 inclusive. The additional airplanes
identified are those having line positions 2184, 2187, 2194 through
2197 inclusive, and 2199. These additional airplanes are operated
currently by non-U.S. operators under foreign registry.
The FAA has reviewed and approved Boeing Service Bulletin 737-57-
1221, Revision 2, dated November 17, 1994, that describes procedures
for modifying the leading edge slat access panel and internal structure
at FSS 250.663. Incorporation of this modification entails sealing the
drain hole in Slat Access Panels 6307L and 6407R, changing the internal
structure of the leading edge panel by creating a drain path to the
strut drain system, and sealing the slat access panel and the internal
structure of the leading edge panel to keep fuel leakage within the new
drain path.
Since an unsafe condition has been identified that is likely to
exist or develop on other airplanes of the same type design, this AD is
being issued to prevent drainage from a fuel leak into the turbine
exhaust area, which could cause an external fire under the wing. This
AD requires modification of the leading edge slat access panel and
internal structure at FSS 250.663. The actions are required to be
accomplished in accordance with the service bulletin described
previously. This AD applies only to Model 737-300, -400, and -500
series airplanes having line positions 2184, 2187, 2194 through 2197
inclusive, and 2199.
Note: The FAA's normal policy is that when an AD requires a
substantive change, such as a change (expansion) in its
applicability, the ``old'' AD is superseded by removing it from the
system and a new AD is added. In the case of this AD action, the FAA
normally would have proposed superseding AD 94-06-11 to expand its
applicability to include the additional affected airplanes. However,
in reconsideration of the entire fleet size that would be affected
by a supersedure action, and the consequent workload associated with
revising maintenance record entries, the FAA has determined that a
less burdensome approach is to issue a separate AD applicable only
to these additional airplanes. This AD does not supersede AD 94-06-
11; airplanes listed in the applicability of AD 94-06-11 are
required to continue to comply with the requirements of that AD.
This AD is a separate AD action, and is applicable on to Model 737-
300, -400, and -500 series airplanes, line positions 2184, 2187,
2194 through 2197 inclusive, and 2199.]
As a result of recent communications with the Air Transport
Association (ATA) of America, the FAA has learned that, in general,
some operators may misunderstand the legal effect of AD's on airplanes
that are identified in the applicability provision of the AD, but that
have been altered or repaired in the area addressed by the AD. The FAA
points out that all airplanes identified in the applicability provision
of an AD are legally subject to the AD. If an airplane has been altered
or repaired in the affected area in such a way as to affect compliance
with the AD, the owner or operator is required to obtain FAA approval
for an alternative method of compliance with the AD, in accordance with
the paragraph of each AD that provides for such approvals. A note has
been included in this rule to clarify this requirement.
None of the Model 737-300, -400, or -500 series airplanes affected
by this action is on the U.S. Register. All airplanes included in the
applicability of this rule currently are operated by non-U.S. operators
under foreign registry; therefore, they are not directly affected by
this AD action. However, the FAA considers that this rule is necessary
to ensure that the unsafe condition is addressed in the event that any
of these subject airplanes are imported and placed on the U.S. Register
in the future.
Should an affected airplane be imported and placed on the U.S.
Register in the future, it would require approximately 10 work hours to
accomplish the required actions, at an average labor charge of $60 per
work hour. The cost of required parts is expected to be negligible.
Based on these figures, the total cost impact of this AD would be $600
per airplane.
Since this AD action does not affect any airplane that is currently
on the U.S. register, it has no adverse economic impact and imposes no
additional burden on any person. Therefore, notice and public
procedures hereon are unnecessary and the amendment may be made
effective in less than 30 days after publication in the Federal
Register.
Comments Invited
Although this action is in the form of a final rule and was not
preceded by notice and 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
[[Page 3741]]
submitted in response to this rule must submit a self-addressed,
stamped postcard on which the following statement is made: ``Comments
to Docket Number 94-NM-217-AD.'' The postcard will be date stamped and
returned to the commenter.
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.
For the reasons discussed above, I certify that this action (1) is
not a ``significant regulatory action'' under Executive Order 12866;
(2) is not a ``significant rule'' under DOT Regulatory Policies and
Procedures (44 FR 11034, February 26, 1979); and (3) will not have a
significant economic impact, positive or negative, on a substantial
number of small entities under the criteria of the Regulatory
Flexibility Act. A final evaluation has been prepared for this action
and it is contained in the Rules Docket. A copy of it 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. App. 1354(a), 1421 and 1423; 49 U.S.C.
106(g); and 14 CFR 11.89.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by adding the following new
airworthiness directive:
94-26-13 Boeing: Amendment 39-9108. Docket 94-NM-217-AD.
Applicability: Model 737-300, -400, and -500 series airplanes;
line positions 2184, 2187, 2194 through 2197 inclusive, and 2199;
certificated 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 use the authority
provided in paragraph (b) to request approval from the FAA. This
approval may address either no action, if the current configuration
eliminates the unsafe condition; or different actions necessary to
address the unsafe condition described in this AD. Such a request
should include an assessment of the effect of the changed
configuration on the unsafe condition addressed by this AD. In no
case does the presence of any modification, alteration, or repair
remove any airplane from the applicability of this AD.
Compliance: Required as indicated, unless accomplished
previously.
To prevent drainage from a fuel leak into the turbine exhaust
area, which could cause an external fire under the wing, accomplish
the following:
(a) Within 24 months after the effective date of this AD, modify
the leading edge slat access panel and internal structure at Front
Spar Station (FSS) 250.663 in accordance with Boeing Service
Bulletin 737-57-1221, Revision 2, dated November 17, 1994.
(b) 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 Aircraft Certification
Office (ACO), FAA, Transport Airplane Directorate. 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.
(c) 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.
(d) The modification shall be done in accordance with Boeing
Service Bulletin 737-57-1221, Revision 2, dated November 17, 1994.
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.
(e) This amendment becomes effective on February 3, 1995.
Issued in Renton, Washington, on December 21, 1994.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 95-1362 Filed 1-18-95; 8:45 am]
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