[Federal Register Volume 64, Number 20 (Monday, February 1, 1999)]
[Proposed Rules]
[Pages 4791-4793]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-2271]
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Proposed Rules
Federal Register
________________________________________________________________________
This section of the FEDERAL REGISTER contains notices to the public of
the proposed issuance of rules and regulations. The purpose of these
notices is to give interested persons an opportunity to participate in
the rule making prior to the adoption of the final rules.
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Federal Register / Vol. 64, No. 20 / Monday, February 1, 1999 /
Proposed Rules
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 98-NM-273-AD]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 737-200C Series Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: This document proposes the supersedure of an existing
airworthiness directive (AD), applicable to all Boeing Model 737-200C
series airplanes, that currently requires a one-time external detailed
visual inspection to detect cracks of the fuselage skin in the lower
lobe cargo compartment; repetitive internal detailed visual inspections
to detect cracks of the frames in the lower lobe cargo compartment; and
repair of cracked parts. That AD also provides for an optional
preventative modification that constitutes terminating action for the
repetitive inspections. This action would require accomplishment of the
previously optional terminating modification. This proposal is prompted
by reports of cracking in the body frames between stringers 19 left and
25 left and at body stations 360 to 500B. The actions specified by the
proposed AD are intended to prevent opening or loss of the cargo door
during flight, and consequent rapid decompression of the airplane.
DATES: Comments must be received by March 18, 1999.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-114,
Attention: Rules Docket No. 98-NM-273-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: Nenita Odesa, Aerospace Engineer,
Airframe Branch, ANM-120S, FAA, Transport Airplane Directorate, Seattle
Aircraft Certification Office, 1601 Lind Avenue, SW., Renton,
Washington 98055-4056; telephone (425) 227-2557; 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-273-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-273-AD, 1601 Lind Avenue, SW., Renton, Washington
98055-4056.
Discussion
On June 25, 1993, the FAA issued AD 93-13-02, amendment 39-8615 (58
FR 36863, July 9, 1993), applicable to all Boeing Model 737-200C series
airplanes, to require a one-time external detailed visual inspection to
detect cracks of the fuselage skin in the lower lobe cargo compartment;
repetitive internal detailed visual inspections to detect cracks of the
frames in the lower lobe cargo compartment; and repair of cracked
parts. That AD also provides for an optional preventative modification
that constitutes terminating action for the repetitive inspections.
That action was prompted by reports of cracking in the body frames
between stringers 19 left and 25 left and at body stations 360 to 500B.
The requirements of that AD are intended to prevent a cargo door from
opening while the airplane is in flight, which could result in rapid
decompression of the airplane.
Actions Since Issuance of Previous Rule
When AD 93-13-02 was issued, it contained a provision for an
optional preventative modification that involves installation of
doublers on the frames located between stringers 19 left and 25 left
and at body stations 360 to 500B, which, if accomplished, constitutes
terminating action for the required repetitive inspections. This action
proposes to require accomplishment of the previously optional
terminating modification in accordance with Boeing Service Bulletin
737-53A1160, Revision 1, dated April 29, 1993. (That service bulletin
was referenced as the appropriate source of service information in AD
93-13-02 for accomplishment of the modification.)
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 supersede AD 93-13-02 to continue to require a one-
time external detailed visual inspection to detect cracks of the
fuselage skin in the lower lobe cargo compartment; repetitive internal
detailed visual inspections to detect cracks of the frames in the lower
lobe cargo compartment; and repair of cracked parts. In addition, the
proposed
[[Page 4792]]
AD would require accomplishment of the previously optional terminating
modification.
Differences Between Proposed Rule and Service Bulletin
Operators should note that this AD proposes to require the
modification of certain fuselage frames, as described in Boeing Service
Bulletin 737-53A1160, Revision 1, as terminating action for the
repetitive inspections. Incorporation of this modification was
classified as optional in that service bulletin.
The FAA has determined that long-term continued operational safety
will be better assured by design changes to remove the source of the
problem, rather than by repetitive inspections. Long-term inspections
may not be providing the degree of safety assurance necessary for the
transport airplane fleet. This, coupled with a better understanding of
the human factors associated with numerous continual inspections, has
led the FAA to consider placing less emphasis on inspections and more
emphasis on design improvements. The proposed modification requirement
is in consonance with these conditions.
Cost Impact
There are approximately 90 airplanes of the affected design in the
worldwide fleet. The FAA estimates that 18 airplanes of U.S. registry
would be affected by this proposed AD.
The inspections that are currently required by AD 93-13-02, and
retained in this proposed AD, take approximately 12 work hours per
airplane to accomplish, at an average labor rate of $60 per work hour.
Based on these figures, the cost impact of the currently required
inspections on U.S. operators is estimated to be $12,960, or $720 per
airplane, per inspection cycle.
The new modification that is proposed in this AD action would take
approximately 160 work hours per airplane to accomplish, at an average
labor rate of $60 per work hour. Required parts would cost
approximately $5,500 per airplane. Based on these figures, the cost
impact of the modification proposed by this AD on U.S. operators is
estimated to be $271,800, or $15,100 per airplane.
The cost impact figures discussed above are based on assumptions
that no operator has yet accomplished any of the current or 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 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 removing amendment 39-8615 (58 FR
36863, July 9, 1993), and by adding a new airworthiness directive (AD),
to read as follows:
Boeing: Docket 98-NM-273-AD. Supersedes AD 93-13-02, Amendment 39-
8615.
Applicability: All Model 737-200C series airplanes, 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 request approval for an
alternative method of compliance in accordance with paragraph (d)(1)
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 opening or loss of the cargo door during flight, and
consequent rapid decompression of the airplane, accomplish the
following:
Restatement of Requirements of AD 93-13-02
(a) Prior to the accumulation of 29,000 flight cycles or within
250 flight cycles after August 9, 1993 (the effective date AD 93-13-
02, amendment 39-8615), whichever occurs later, accomplish an
external detailed visual inspection to detect cracks of the fuselage
skin between stringers 19 left and 25 left and at body stations 360
to 540, in accordance with Boeing Alert Service Bulletin 737-
53A1160, dated October 24, 1991; or Boeing Service Bulletin 737-
53A1160, Revision 1, dated April 29, 1993. If any crack is found,
prior to further flight, accomplish the requirements of paragraphs
(a)(1) and (a)(2) of this AD.
(1) Perform an internal detailed visual inspection to detect
cracks of the frames between stringers 19 left and 25 left and at
body stations 360 to 500B, in accordance with either service
bulletin.
(2) Repair all cracks in accordance with a method approved by
the Manager, Seattle Aircraft Certification Office (ACO), FAA,
Transport Airplane Directorate.
(b) Within 3,000 flight cycles after completing the requirements
of paragraph (a) of this AD, unless accomplished within the last
6,000 flight cycles prior to August 9, 1993, perform an internal
detailed visual inspection to detect cracks of the frames between
stringers 19 left and 25 left and at body stations 360 to 500B, in
accordance with Boeing Alert Service Bulletin 737-53A1160, dated
October 24, 1991; or Boeing Service Bulletin 737-53A1160, Revision
1, dated April 29, 1993. Thereafter, repeat the internal detailed
visual inspection at intervals not to exceed 9,000 flight cycles. If
any crack is found, prior to further flight, accomplish the
requirements of paragraph (b)(1) or (b)(2) of this AD, as
applicable.
(1) If any crack is found that does not exceed the limits
specified in the Boeing 737 Structural Repair Manual (SRM), repair
the crack in accordance with the Boeing 737 SRM. Repeat the internal
detailed visual inspection thereafter at intervals not to exceed
9,000 flight cycles.
(2) If any crack is found that exceeds the limits specified in
the Boeing 737 SRM, repair the crack in accordance with a method
approved by the Manager, Seattle ACO. Repeat the internal detailed
visual inspection thereafter at intervals not to exceed 9,000 flight
cycles.
New Requirements of This AD
(c) Prior to the accumulation of 75,000 total flight cycles, or
within 3,000 flight cycles after the effective date of this AD,
whichever occurs later, install doublers on the frames located
between stringers 19 left and 25 left
[[Page 4793]]
and at body stations 360 to 500B, in accordance with Boeing Service
Bulletin 737-53A1160, Revision 1, dated April 29, 1993.
Accomplishment of this modification constitutes terminating action
for the requirements of this AD.
(d)(1) 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.
(d)(2) Alternative methods of compliance approved previously in
accordance with AD 93-13-02, amendment 39-8615, are approved as
alternative methods of compliance with this AD.
Note 2: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Seattle ACO.
(e) 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 January 26, 1999.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 99-2271 Filed 1-29-99; 8:45 am]
BILLING CODE 4910-13-P
