[Federal Register Volume 63, Number 146 (Thursday, July 30, 1998)]
[Proposed Rules]
[Pages 40666-40668]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-20339]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 97-NM-292-AD]
RIN 2120-AA64
Airworthiness Directives; McDonnell Douglas Model DC-9-80 Series
Airplanes and Model MD-88 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 certain McDonnell Douglas
Model DC-9-80 series airplanes and Model MD-88 airplanes, that
currently requires inspection(s) to detect fatigue cracking of the
shock strut cylinder of the main landing gear (MLG), and replacement of
any cracked shock strut cylinder with a serviceable part. That AD also
provides for installation of brake line hydraulic restrictors on the
MLG brake systems, which, if accomplished, terminates the repetitive
inspections. This action would require that the subject inspection be
accomplished repetitively following installation of brake line
hydraulic restrictors. This proposal is prompted by an additional
report of fatigue cracking and subsequent fracturing of the shock strut
cylinder of the MLG. The actions specified by the proposed AD are
intended to prevent collapse of the MLG due to fracturing of the shock
strut cylinder.
DATES: Comments must be received by September 14, 1998.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-114,
Attention: Rules Docket No. 97-NM-292-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 The Boeing Company, Douglas Products Division, 3855
Lakewood Boulevard, Long Beach, California 90846, Attention: Technical
Publications Business Administration, Dept. C1-L51 (2-60). This
information may be examined at the FAA, Transport Airplane Directorate,
1601 Lind Avenue, SW., Renton, Washington; or at the FAA, Los Angeles
Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood,
California.
FOR FURTHER INFORMATION CONTACT: Brent Bandley, Aerospace Engineer,
Airframe Branch, ANM-120L, FAA, Los Angeles Aircraft Certification
Office, 3960 Paramount Boulevard, Lakewood, California 90712; telephone
(562) 627-5237; fax (562) 627-5210.
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 97-NM-292-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. 97-NM-292-AD, 1601 Lind Avenue, SW., Renton, Washington
98055-4056.
Discussion
On October 16, 1995, the FAA issued AD 95-22-06, amendment 39-9413
(60 FR 54417, October 24, 1995), applicable to certain McDonnell
Douglas Model DC-9-80 series airplanes and Model MD-88 airplanes, to
require inspection(s) to detect fatigue cracking of the shock strut
cylinder of the main landing gear (MLG), and replacement of any cracked
shock strut cylinder with a serviceable part. That AD also provides for
installation of brake line hydraulic restrictors on the MLG brake
systems, which, if accomplished, terminates the repetitive inspection
requirement. That action was prompted by a report indicating that
fatigue cracking and subsequent fracturing of the shock strut cylinder
of the MLG occurred due to high stress loads on the cylinder as a
result of braking induced vibration. The requirements of that AD are
intended to prevent such fracturing, which could result in collapse of
the MLG and consequent reduced controllability of the airplane during
landing.
Actions Since Issuance of Previous Rule
Since the issuance of that AD, the FAA has received an additional
report of fatigue cracking and subsequent fracturing of the shock strut
cylinder of the MLG, which collapsed during landing roll of an affected
in-service airplane. Brake line hydraulic restrictors had been
previously installed on this airplane.
Explanation of Relevant Service Information
Subsequent to this incident, the manufacturer issued, and the FAA
reviewed and approved, McDonnell Douglas Alert Service Bulletin MD80-
32A286, Revision 03, dated May 28, 1998. The inspection procedures
described in this revision are identical to those described in the
original version of the alert service bulletin (which was referenced in
AD 95-22-06 as the appropriate source of service information). In
addition, Revision 03
[[Page 40667]]
recommends that these inspections be accomplished on a repetitive basis
following installation of the brake line hydraulic restrictors.
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 95-22-06 to require repetitive dye
penetrant and magnetic particle inspections to detect cracking of the
shock strut cylinder of the MLG following installation of brake line
hydraulic restrictors. The proposed AD also would require replacement
of any cracked shock strut cylinder with either a serviceable part or
new shock strut cylinder. Accomplishment of the replacement with a new
shock strut cylinder constitutes terminating action for the repetitive
inspection requirements. The actions would be required to be
accomplished in accordance with the alert service bulletin described
previously.
Differences Between the AD and the Relevant Service Information
Operators should note that, although the referenced alert service
bulletin describes procedures for installation of brake line hydraulic
restrictors, this proposed AD does not require such an installation.
The FAA has previously issued AD 96-01-09, amendment 39-9485 (61 FR
2407, January 26, 1996) that concerns the subject area on McDonnell
Douglas Model DC-90 series airplanes and Model MD-88 airplanes. That AD
requires installation of hydraulic line restrictors in the MLG. This
proposed AD would not affect the current requirements of AD 96-01-09.
Cost Impact
There are approximately 1,011 McDonnell Douglas Model DC-9-80
series airplanes and Model MD-88 airplanes of the affected design in
the worldwide fleet. The FAA estimates that 625 airplanes of U.S.
registry would be affected by this proposed AD.
The dye penetrant and magnetic particle inspections that are
proposed in this AD action would take approximately 4 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 dye penetrant and
magnetic particle inspections proposed by this AD on U.S. operators is
estimated to be $150,000, or $240 per airplane, per inspection cycle.
The cost impact figure discussed above is 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 39-9413 (60 FR
54417, October 24, 1995), and by adding a new airworthiness directive
(AD), to read as follows:
McDonnell Douglas: Docket 97-NM-292-AD. Supersedes AD 95-22-06,
Amendment 39-9413.
Applicability: Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83
(MD-83), and DC-9-87 (MD-87) series airplanes, and Model MD-88
airplanes; as listed in McDonnell Douglas Alert Service Bulletin
MD80-32A286, dated September 11, 1995; 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 collapse of the main landing gear (MLG) due to
fracturing of the shock strut cylinder, accomplish the following:
Note 2: Where there are differences between the referenced alert
service bulletin and the AD, the AD prevails.
(a) Perform dye penetrant and magnetic particle inspections to
detect cracking of the shock strut cylinder of the MLG, in
accordance with McDonnell Douglas Alert Service Bulletin MD80-
32A286, Revision 03, dated May 28, 1998; at the time specified in
paragraph (a)(1), (a)(2), or (a)(3) of this AD, as applicable.
Note 3: Inspections accomplished prior to the effective date of
this AD in accordance with McDonnell Douglas Alert Service Bulletin
MD80-32A286, Revision 02, dated October 2, 1997, are considered
acceptable for compliance with paragraph (a) of this AD.
(1) For airplanes that, as of the effective date of this AD,
have accumulated less than 1,200 landings since accomplishment of
the brake line hydraulic restrictor installation: Inspect within
1,200 landings after the effective date of this AD. Repeat the
inspections thereafter at intervals not to exceed 1,200 landings for
a total of 4 inspections.
(2) For airplanes that, as of the effective date of this AD,
have accumulated greater than or equal to 1,200 landings and less
than 2,400 landings since accomplishment of the brake line hydraulic
restrictor installation: Inspect within 1,200 landings after the
effective date of this AD. Repeat the inspections thereafter at
intervals not to exceed 1,200 landings for a total of 3 inspections.
(3) For airplanes that, as of the effective date of this AD,
have accumulated greater than or equal to 2,400 landings since
accomplishment of the brake line hydraulic restrictor installation:
Inspect within 1,200 landings after the effective date of this AD.
Repeat the inspections thereafter at intervals not to exceed 1,200
landings for a total of 2 inspections.
(b) If any cracking is detected during any inspection required
by paragraph (a) of this AD, prior to further flight, accomplish
either paragraph (b)(1) or (b)(2) of this AD in accordance with
McDonnell Douglas Alert Service Bulletin MD80-32A286, Revision 03,
dated May 28, 1998.
[[Page 40668]]
(1) Replace the shock strut cylinder with a crack-free
serviceable part and, thereafter, repeat the inspections required by
paragraph (a) of this AD, at the time specified in paragraph (a)(1),
(a)(2), or (a)(3) of this AD, as applicable. Or
(2) Replace the shock strut cylinder with a new shock strut
cylinder. Accomplishment of the replacement constitutes terminating
action for the repetitive inspection requirements of paragraph (a)
of this AD.
Note 4: Replacements accomplished prior to the effective date of
this AD in accordance with McDonnell Douglas Alert Service Bulletin
MD80-32A286, Revision 02, dated October 2, 1997, are considered
acceptable for compliance with paragraph (b) of this AD.
(c) As of the effective date of this AD, no person shall install
on any airplane an MLG shock strut cylinder or MLG assembly unless
that part has been inspected and found to be crack free, in
accordance with McDonnell Douglas Alert Service MD80-32A286,
Revision 02, dated October 2, 1997, or Revision 03, dated May 28,
1998.
(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, Los Angeles 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, Los Angeles ACO.
Note 5: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Los Angeles ACO.
(d)(2) Alternative methods of compliance, approved previously in
accordance with AD 95-22-06, amendment 39-9413, are approved as
alternative methods of compliance with this AD.
(e) Special flight permits may be issued in accordance with
Secs. 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 24, 1998.
S. R. Miller,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 98-20339 Filed 7-29-98; 8:45 am]
BILLING CODE 4910-13-U
