[Federal Register Volume 63, Number 135 (Wednesday, July 15, 1998)]
[Proposed Rules]
[Pages 38116-38118]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-18779]
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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. 63, No. 135 / Wednesday, July 15, 1998 /
Proposed Rules
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 98-NM-148-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 repetitive ultrasonic
inspections to detect broken bolts that attach the terminal support
fittings to the upper part of the Body Station 1088 bulkhead, and
corrective actions, if necessary. This proposal also would require
eventual replacement of the existing bolts with new, improved bolts,
which, when accomplished, would terminate the requirements of the AD.
This proposal is prompted by reports that bolts that attach the
terminal support fittings to the upper part of the bulkhead were found
broken. The actions specified by the proposed AD are intended to
prevent such broken bolts, which could result in reduced structural
integrity of the vertical fin installation and possible loss of the
vertical fin.
DATES: Comments must be received by August 31, 1998.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-114,
Attention: Rules Docket No. 98-NM-148-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-148-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-148-AD, 1601 Lind Avenue, SW., Renton, Washington
98055-4056.
Discussion
The FAA has received reports indicating that broken bolts were
found in the terminal support fittings that attach the aft spar of the
vertical fin to the upper part of the bulkhead at Body Station 1088 on
Boeing Model 737 series airplanes. The broken bolts were made of H-11
steel alloy. Bolts made of such material are susceptible to stress
corrosion cracking. Such broken bolts, if not corrected, could result
in reduced structural integrity of the vertical fin installation, and
multiple broken bolts could result in loss of the vertical fin.
Explanation of Relevant Service Information
The FAA has reviewed and approved Boeing Service Bulletin 737-53-
1107, Revision 3, dated August 26, 1993; as revised by Notices of
Status Change 737-53-1107 NSC 3, dated June 9, 1994, and 737-53-1107
NSC 4, dated September 22, 1994; and Boeing Service Bulletin 737-53-
1107, Revision 4, dated February 8, 1996. These service bulletins
describe procedures for repetitive ultrasonic inspections to detect
broken bolts that attach the terminal support fittings to the upper
part of the Body Station 1088 bulkhead, and replacement of the existing
bolts with new, improved bolts. The replacement includes removing the
bolts, performing an eddy current inspection to detect cracking or
corrosion of the bolt holes, oversizing the bolt holes, and installing
new Inconel bolts. Installation of the new Inconel bolts would
eliminate the need for the repetitive inspections described previously.
Accomplishment of the actions specified in the service bulletins is
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 bulletins and notices of status change described
previously, except as discussed below.
Differences Between Proposed Rule and Service Bulletin
Operators should note that, although the service bulletins specify
that the
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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.
Cost Impact
There are approximately 1,485 airplanes of the affected design in
the worldwide fleet. The FAA estimates that 630 airplanes of U.S.
registry would be affected by this proposed AD.
It would take approximately 3 work hours per airplane to accomplish
the proposed inspection, at an average labor rate of $60 per work hour.
Based on these figures, the cost impact of the inspection proposed by
this AD on U.S. operators is estimated to be $113,400, or $180 per
airplane, per inspection cycle.
It would take approximately 9 work hours per airplane to accomplish
the proposed replacement, at an average labor rate of $60 per work
hour. Required parts would cost approximately $471 per airplane. Based
on these figures, the cost impact of the replacement proposed by this
AD on U.S. operators is estimated to be $636,930, or $1,011 per
airplane.
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 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-148-AD.
Applicability: Model 737 series airplanes, line numbers 1
through 1485 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
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 (c) 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 broken bolts that attach the terminal support
fittings to the upper part of the Body Station (BS) 1088 bulkhead,
which could result in reduced structural integrity of the vertical
fin installation and possible loss of the vertical fin, accomplish
the following:
(a) Within 18 months after the effective date of this AD,
perform an ultrasonic inspection to detect broken bolts that attach
the terminal support fittings to the upper part of the BS 1088
bulkhead, in accordance with Boeing Service Bulletin 737-53-1107,
Revision 3, dated August 26, 1993; as revised by Notice of Status
Change 737-53-1107 NSC 3, dated June 9, 1994, and Notice of Status
Change 737-53-1107 NSC 4, dated September 22, 1994; or Boeing
Service Bulletin 737-53-1107, Revision 4, dated February 8, 1996.
(1) If no broken bolt is found, repeat the ultrasonic inspection
thereafter at intervals not to exceed 18 months.
(2) If any broken bolt is found, prior to further flight,
perform the actions specified in paragraph (b) of this AD.
(b) Prior to the accumulation of 20 years since date of
manufacture of the airplane, or within 18 months after the effective
date of this AD, whichever occurs later, remove all 16 H-11 steel
alloy bolts that attach the terminal support fittings to the upper
part of the bulkhead, and perform an eddy current inspection to
detect cracking or corrosion of the bolt holes, in accordance with
Figure 2 of Boeing Service Bulletin 737-53-1107, Revision 3, dated
August 26, 1993; as revised by Notice of Status Change 737-53-1107
NSC 3, dated June 9, 1994, and Notice of Status Change 737-53-1107
NSC 4, dated September 22, 1994; or Boeing Service Bulletin 737-53-
1107, Revision 4, dated February 8, 1996.
(1) If no cracking or corrosion is found, prior to further
flight, oversize all 16 bolt holes and install new Inconel bolts, in
accordance with Figure 2 of the service bulletin. Accomplishment of
this installation constitutes terminating action for the repetitive
inspection requirements of this AD.
(2) If any corrosion is found, prior to further flight, oversize
the bolt hole within the limits specified in Figure 2, Step 4, of
the service bulletin, and install a new Inconel bolt, in accordance
with Figure 2 of the service bulletin. Accomplishment of the
installation for all 16 bolt holes constitutes terminating action
for the repetitive inspection requirements of this AD. If corrosion
does not clean up within the limits specified in Figure 2, Step 4,
of the service bulletin, prior to further flight, repair in
accordance with a method approved by the Manager, Seattle Aircraft
Certification Office (ACO), FAA, Transport Airplane Directorate.
(3) If any cracking is found, prior to further flight, oversize
the bolt hole within the limits specified in Figure 2, Step 5, of
the service bulletin, and perform another eddy current inspection to
ensure cracks have been removed, in accordance with Figure 2 of the
service bulletin.
(i) If, after oversizing, no cracking is found, prior to further
flight, oversize the bolt hole again, and install a new Inconel
bolt, in accordance with Figure 2 of the service bulletin.
Accomplishment of the installation for all 16 bolt holes constitutes
terminating action for the repetitive inspection requirements of
this AD.
(ii) If, after oversizing, any cracking is found, prior to
further flight, repair in accordance with a method approved by the
Manager, Seattle ACO.
Note 2: Replacement of all H-11 steel alloy bolts accomplished
prior to the effective date of this AD, in accordance with Boeing
Service Bulletin 737-53-1107, dated October 15, 1987; Revision 1,
dated June 22, 1989; or Revision 2, dated September 10, 1992; is
considered acceptable for compliance with the applicable actions
specified in paragraph (b) of this AD.
(c) 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.
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Note 3: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Seattle ACO.
(d) 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 July 8, 1998.
S.R. Miller,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 98-18779 Filed 7-14-98; 8:45 am]
BILLING CODE 4910-13-U
