AD 2000-10-06 Airworthiness Directives; MD Helicopters Inc. Model MD900 Helicopters

Models named: MD900. Read the applicability below — it usually turns on serial or part numbers too.

Model MD900 helicopters, certificated in any category. Note 1: This AD applies to each helicopter 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 helicopters 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) 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 failure of the drive shaft due to fatigue, which could result in total loss of drive to the main rotor hub and subsequent loss of control of the helicopter; accomplish the following: (a) Before accumulating 1,450 hours time-in-service (TIS), visually inspect the drive shaft assembly to determine which part number (P/N) is installed. If necessary, remove the drive plate cover to access the P/N located on the top edge of the drive shaft assembly. If the number of hours TIS on the drive shaft assembly is unknown, use the total hours TIS on the helicopter. Note 2: Do not confuse the P/N of the drive shaft subassembly, P/N 900D2436028-101, 900D2436026-101, or 900D2436030-101 as the P/N of the drive shaft assembly. (1) If a drive shaft assembly, P/N 900D2436530-101, is installed, no further action is required by this AD. (2) If a drive shaft assembly other than P/N 900D2436530-101 is installed and is not marked with a P/N, before further flight, use an indelible ink fine tip marking pen to mark the following information on the edge of the drive shaft assembly in line with the engraved subassembly number: (i) P/N 900D2436528-101 and the serial number (S/N) of the drive shaft subassembly if the subassembly is P/N 900D2436028-101. When the ink dries, apply a clear coat over the P/N and S/N, or (ii) P/N 900D6400004-101 and the S/N of the drive shaft subassembly if the subassembly is P/N 900D2436026-101. When the ink drives, apply a clear coat over the P/N and S/N. (b) For a drive shaft assembly with 1,450 or more hours TIS, before further flight, accomplish paragraph (a) of this AD. Note 3: MD Helicopters Inc. Service Bulletin SB900-062 R1, dated December 16, 1999, applies to the subject of this AD. (c) After accomplishing the requirements of paragraph (a) of this AD, before further flight, determine the hours TIS of the drive shaft assembly. Record the hours TIS on a current or newly created component history card or equivalent record. If the drive shaft assembly has reached or exceeded its life limit, replace the drive shaft assembly with an airworthy drive shaft assembly before further flight. Note 4: The Airworthiness Limitations Section, section 04, of the MD-900 Rotorcraft Maintenance Manual (CSP-900RMM-2), Revision 6, dated December 23, 1999, pertains to the subject of this AD. (d) 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, FAA. Operators shall submit their requests through an FAA Principal Maintenance Inspector, who may concur or comment and then send it to the Manager, Los Angeles Aircraft Certification Office. Note 5: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Los Angeles Aircraft Certification Office. (e) Special flight permits may be issued in accordance with §§ 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the helicopter to a location where the requirements of this AD can be accomplished. (f) This amendment becomes effective on June 1, 2000. Issued in Fort Worth, Texas, on May 5, 2000. Eric Bries, Acting Manager, Rotorcraft Directorate, Aircraft Certification Service. [FR Doc. 00-12353 Filed 5-16-00; 8:45 am] BILLING CODE 4910-13-U