Airworthiness directives: McDonnell Douglas,
[Federal Register: July 30, 1998 (Volume 63, Number 146)]
[Proposed Rules]
[Page 40666-40668]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr30jy98-23]
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).
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 filedin 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
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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
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The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701.
Sec. 39.13 [Amended]
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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.
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(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. 98-20339Filed7-29-98; 8:45 am]
BILLING CODE 4910-13-U
