AD 98-13-35 Airworthiness Directives; McDonnell Douglas Model DC-9 and DC-9- 80 Series Airplanes, Model MD-88 Airplanes, and C-9 (Military) Series Airplanes

Models named: DC-9-10, -20, -30, -40, -50 series, MD-88. Read the applicability below — it usually turns on serial or part numbers too.

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.

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 [[Page 13892]] 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. 99-6980 Filed 3-22-99; 8:45 am] BILLING CODE 4910-13-U