AD 97-02-10 Airworthiness Directives; McDonnell Douglas Model DC-9, DC-9-80, and C-9 (Military) Series Airplanes, Model MD-88 Airplanes, and Model MD-90 Airplanes

Models named: MD-88, MD-90. Read the applicability below — it usually turns on serial or part numbers too.

Model DC-9, DC-9-80, and C-9 (military) series airplanes, Model MD-88 airplanes, and Model MD-90 airplanes; as listed in McDonnell Douglas Alert Service Bulletins DC9-32A298 [for Model DC-9, DC-9-80, and C-9 (military) series airplanes, and Model MD-88 airplanes], and McDonnell Douglas Alert Service Bulletin MD90- 32A019 [for Model MD-90 airplanes], both dated December 19, 1996; certificated in any category. Note 1: This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been otherwise 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 (e) 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 fracturing of the upper lock link assembly of the nose landing gear (NLG) due to fatigue cracking, and the consequent failure of the NLG to extend fully, which could lead to injury to passengers and flight crew, and damage to the airplane, accomplish the following: (a) Prior to the accumulation of 10,000 total cycles of the NLG, or within 90 days after the effective date of this AD, whichever occurs later, conduct a visual check of the upper lock link assembly of the NLG to determine its part and serial number, in accordance with McDonnell Douglas Alert Service Bulletin DC9-32A298 [for Model DC-9, DC-9-80, and C-9 (military) series airplanes, and Model MD-88 airplanes], or McDonnell Douglas Alert Service Bulletin MD90-32A019 [for Model MD-90 airplanes], both dated December 19, 1996, as applicable. (b) If the part number and serial number of the upper lock link assembly are listed in paragraph (b)(1) or (b)(2) of this AD (``an exempt upper lock link assembly''), no further action is required. Note 2: An ``exempt upper lock link assembly'' as specified in paragraph (b) of this AD is an assembly that is manufactured of forged aluminum. (1) For Model DC-9, DC-9-80, and C-9 (military) series airplanes, and Model MD-88 airplanes: Part Number (P/N) 3914464-(any configuration) having serial numbers (S/N) HMI001 through HMI172 inclusive, or S/N WPI1000 and subsequent; or P/N 5920472-(any configuration) having any serial number. (2) For Model MD-90 airplanes: P/N 3914464-503 having S/N HMI001 through HMI172 inclusive, or S/N WPI1000 and subsequent. (c) If the part number and serial number of the upper lock link assembly are not listed in paragraph (b)(1) or (b)(2) of this AD ( a ``possible discrepant upper lock link assembly''), except as provided by paragraph (c)(3) of this AD, prior to further flight, conduct either a high frequency eddy current inspection or a Type I fluorescent penetrant inspection of this assembly to detect fatigue cracks, in accordance with McDonnell Douglas Alert Service Bulletin DC9-32A298 [for Model DC-9, DC-9-80, and C-9 (military) series airplanes, and Model MD-88 airplanes], or McDonnell Douglas Alert Service Bulletin MD90-32A019 [for Model MD-90 airplanes], both dated December 19, 1996. Note 3: A ``possible discrepant upper lock link assembly'' as specified in paragraph (c) of this AD is an assembly that may be manufactured from aluminum plate. (1) If no crack is detected, repeat either type of inspection required by paragraph (c) of this AD at intervals not to exceed 5,000 cycles of the NLG. (2) If any crack is detected, prior to further flight, replace the pin assembly of the NLG in accordance with the applicable alert service bulletin. (3) A Type I fluorescent penetrant inspection of the upper lock link assembly that has been conducted within the last 12 months prior to the effective date of this AD and in accordance with the DC-9 Overhaul Manual or MD-90 Component Manual, Chapter 20-70-2, is considered acceptable for compliance with the initial inspection required by paragraph (c) of this AD. If no crack was detected during that inspection, subsequent repetitive inspections are required to be accomplished at the intervals specified in paragraph (c)(1) of this AD. (d) When replacement of the pin assembly of the NLG is required in accordance with paragraph (c)(1) or (c)(2) of this AD: (1) If the pin assembly is replaced with a new assembly that contains a possible discrepant upper lock assembly: After the pin assembly has been replaced, repeat the inspection required by paragraph (c) of this AD prior to the accumulation of 10,000 cycles of the NLG. (2) If the pin assembly is replaced with a serviceable assembly that contains a possible discrepant upper lock assembly: After the pin assembly has been replaced, repeat the inspection required by paragraph (c) of this AD either prior to the accumulation of 10,000 total cycles of the NLG for that pin assembly, or prior to further flight, whichever occurs later. (3) If the pin assembly is replaced with a pin assembly that contains an exempt upper lock link assembly: No further action is required. This installation constitutes terminating action for the repetitive inspections required by this AD. (e) 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 [[Page 3784]] an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Los Angeles ACO. Note 4: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Los Angeles ACO. (f) 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. (g) The visual check, repetitive inspections, and replacement of the pin assembly of the NLG shall be done in accordance with McDonnell Douglas Alert Service Bulletin DC9-32A298, dated December 19, 1996; or McDonnell Douglas Alert Service Bulletin MD90-32A019, dated December 19, 1996; as applicable. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from McDonnell Douglas Corporation, 3855 Lakewood Boulevard, Long Beach, California 90846, Attention: Technical Publications Business Administration, Department C1-L51 (2-60). Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, Transport Airplane Directorate, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, California; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. (h) This amendment becomes effective on February 11, 1997. Issued in Renton, Washington, on January 14, 1997. S. R. Miller, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 97-1438 Filed 1-24-97; 8:45 am] BILLING CODE 4910-13-P