Airworthiness directives: McDonnell Douglas,

[Federal Register: March 23, 1999 (Volume 64, Number 55)]

[Rules and Regulations]

[Page 13890-13892]

From the Federal Register Online via GPO Access [wais.access.gpo.gov]

[DOCID:fr23mr99-6]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96-NM-203-AD; Amendment 39-11086; AD 98-13-35 R1]

RIN 2120-AA64

Airworthiness Directives; McDonnell Douglas Model DC-9 and DC-9- 80 Series Airplanes, Model MD-88 Airplanes, and C-9 (Military) Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; correction.

SUMMARY: This amendment corrects information in an existing airworthiness directive (AD), applicable to certain McDonnell Douglas Model DC-9 and DC-9-80 series airplanes, Model MD-88 airplanes, and C-9 (military) series airplanes, that currently requires repetitive high frequency eddy current inspections of certain areas of the fuselage to detect cracks of the skin and/or longeron, and various follow-on actions. That AD also requires installation of a preventative modification, which terminates the repetitive inspections. The actions specified in that AD are intended to prevent fatigue cracks, which could result in loss of the structural integrity of the fuselage and, consequently, lead to rapid depressurization of the airplane. This amendment corrects the requirements of the current AD by indicating the specific area in which the subject inspection must be conducted. This amendment is prompted by communication received from the manufacturer that the current requirements of the AD are different than the service information referenced as the appropriate service information in the current AD.

EFFECTIVE DATE: July 30, 1998.

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: On June 17, 1998, the FAA issued AD 98-13- 35, amendment 39-10626 (63 FR 34585, June 25, 1998), which is applicable to certain McDonnell Douglas Model DC-9 and DC-9-80 series airplanes, Model MD-88 airplanes, and C-9 (military) series airplanes. That AD requires repetitive high frequency eddy current inspections of certain areas of the

[[Page 13891]]

fuselage to detect cracks of the skin and/or longeron, and various follow-on actions. That AD also requires installation of a preventative modification, which terminates the repetitive inspections. That action was prompted by reports indicating that, due to material fatigue caused by installation preload and cabin pressurization cycles, fatigue cracks were found in the skin and longerons of the fuselage. The actions required by that AD are intended to prevent such fatigue cracks, which could result in loss of the structural integrity of the fuselage and, consequently, lead to rapid depressurization of the airplane.

Actions Since Issuance of Previous Rule

Since the issuance of AD 98-13-35, the FAA has received information from the manufacturer that the specified area of the initial inspection requirements of paragraph (a) of that AD differs from the service information provided in McDonnell Douglas DC-9 Service Bulletin 53-235, dated September 15, 1993 (cited in the AD as the appropriate source of service information for accomplishment of the required actions).

The FAA's intent in AD 98-13-35 was to require the actions described in McDonnell Douglas DC-9 Service Bulletin 53-235. In order to prevent operators from misinterpreting the specific area of the initial inspection, the FAA finds that the inspection requirements of paragraph (a) must be revised to specify inspection only of the fuselage, in lieu of the fuselage skin and/or longeron. Accordingly, this action revises paragraph (a) of the existing AD to remove reference to inspection of the longeron and to limit the area that is subject to the inspection (skin between stations Y=160.000 and Y=218.000; skin at the longeron attachments).

Action is taken herein to clarify and correct these requirements of AD 98-13-35 and to correctly add the AD as an amendment to section 39.13 of the Federal Aviation Regulations (14 CFR 39.13).

The final rule is being reprinted in its entirety for the convenience of affected operators. The effective date remains July 30, 1998.

Since this action only clarifies and corrects a current requirement, it has no adverse economic impact and imposes no additional burden on any person. Therefore, notice and public procedures hereon are unnecessary.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Safety.

Adoption of the Correction

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. 106(g), 40113, 44701.

   Sec. 39.13 [Amended]

2. Section 39.13 is amended by removing amendment 39-10626 (63 FR 34585, June 25, 1998), and by adding a new airworthiness directive (AD), amendment 39-11086, to read as follows:

   98-13-35 R1 McDonnell Douglas: Amendment 39-11086. Docket 96-NM- 203-AD. Revises AD 98-13-35, Amendment 39-10626.

   Applicability: Model DC-9-10, -20, -30, -40, and -50 series airplanes; Model DC-9-81 (MD-81), -82 (MD-82), -83 (MD-83), and -87 (MD-87) series airplanes; Model MD-88 airplanes; and C-9 (military) series airplanes; as listed in McDonnell Douglas DC-9 Service Bulletin 53-235, dated September 15, 1993; 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 (f) 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 fatigue cracks in the skin and longerons of the fuselage, which could result in loss of the structural integrity of the fuselage and, consequently, lead to rapid depressurization of the airplane, accomplish the following:

   (a) Perform a high frequency eddy current (HFEC) inspection of the external areas of the fuselage to detect cracks of the skin between stations Y=160.000 and Y=218.000, and of the skin at the longeron attachments between stations Y=160.000 and Y=180.000, longeron 4 left and longeron 5 left, in accordance with McDonnell Douglas DC-9 Service Bulletin 53-235 dated September 15, 1993. Perform the inspection at the time specified in paragraph (a)(1) or (a)(2) of this AD, as applicable.

   Note 2: Where there are differences between this AD and the referenced service bulletin, the AD prevails.

   (1) For airplanes other than those identified in paragraph (a)(2) of this AD: Inspect prior to the accumulation of 30,000 total landings, or within 8,000 landings after the effective date of this AD, whichever occurs later.

   (2) For airplanes that have been inspected previously in accordance with Task C46-53300 of the Corrosion Prevention and Control Program (CPCP), as required by AD 92-22-8-R1, amendment 39- 8591, within 6,000 flight cycles prior to the effective date of this AD: Inspect within 12,000 landings after the effective date of this AD.

   (b) Condition 1 (No Cracks). If no crack is detected during any inspection required by this AD, accomplish either paragraph (b)(1) or (b)(2) of this AD, in accordance with McDonnell Douglas DC-9 Service Bulletin 53-235, dated September 15, 1993.

   (1) Condition 1, Option I (Repetitive Inspection). Repeat the HFEC inspection required by paragraph (a) of this AD, and the aided visual inspection specified in paragraph 2.E. of the Accomplishment Instructions of the service bulletin, at intervals not to exceed 10,000 landings.

   (2) Condition 1, Option II (Terminating Action Modification). Accomplish the preventative modification installation of clips and doublers between stations Y=160.000 and Y=218.000, in accordance with the service bulletin. Accomplishment of the modification constitutes terminating action for the repetitive inspection requirements of this AD.

   (c) Condition 2 (Skin Cracks). If any skin crack is detected during any inspection required by this AD, prior to further flight, repair it in accordance with McDonnell Douglas DC-9 Service Bulletin 53-235, dated September 15, 1993. After repair, accomplish either paragraph (b)(1) or (b)(2) of this AD.

   (d) Condition 3 (Longeron Cracks). If any longeron crack is detected during any inspection required by this AD, prior to further flight, repair it in accordance with McDonnell Douglas DC-9 Service Bulletin 53-235, dated September 15, 1993. After repair, accomplish either paragraph (b)(1) or (b)(2) of this AD.

   (e) Prior to the accumulation of 100,000 total landings, or within 4 years after the effective date of this AD, whichever occurs later, accomplish the preventative modification specified in paragraph 2.J. of the Accomplishment Instructions of McDonnell Douglas DC-9 Service Bulletin 53-235, dated September 15, 1993. Accomplishment of the modification constitutes terminating action for the requirements of this AD.

   Alternative Methods of Compliance

   (f) 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

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   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 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Los Angeles ACO.

   Special Flight Permits

   (g) 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.

   (h) The effective date of this amendment remains July 30, 1998.

   Issued in Renton, Washington, on March 16, 1999. Darrell M. Pederson, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.

   [FR Doc. 99-6980Filed3-22-99; 8:45 am]

   BILLING CODE 4910-13-U