AD 99-23-18 Airworthiness Directives; Bell Helicopter Textron Canada Model 407 Helicopters

Models named: 407. Read the applicability below — it usually turns on serial or part numbers too.

Model 407 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 (c) 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.

Prior to further flight, unless accomplished previously. To prevent a fatigue failure of certain parts that may have exceeded revised life limits and subsequent loss of control of the helicopter, accomplish the following: (a) Remove and replace with an airworthy part any of the following parts that exceed their revised life limits. Annotate the component history card or equivalent record with the revised life limits. ---------------------------------------------------------------------------------------------------------------- Part Part No. Former life limit Revised life limit ---------------------------------------------------------------------------------------------------------------- Drive ring set........................ 406-010-126-107 49,000 RIN............... 48,000 RIN. Main rotor mast....................... 407-040-038-101 5,000 hours TIS or 25,000 5,000 hours TIS or 18,000 RIN. RIN. Left-hand pylon side beam............. 407-010-201-101 1,000 hours TIS.......... 1,000 hours TIS or 5,500 RIN. Right-hand pylon side beam............ 407-010-203-101 1,000 hours TIS.......... 1,000 hours TIS or 5,500 RIN. Pylon restraint spring................ 407-010-206-103 On-condition............. 5,000 hours TIS. ---------------------------------------------------------------------------------------------------------------- Note 2: Bell Helicopter Textron Canada (BHTC) Alert Service Bulletin 407-98-22, dated December 10, 1998, and Revision 9 to Chapter 4 of the Maintenance Manual BHT-407-MM-1 dated November 30, 1998, pertain to the subject of this AD. (b) Revise the Airworthiness Limitations Schedule of the BHTC Model 407 maintenance manual by establishing or revising the retirement life for the parts as shown in paragraph (a). (c) 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, Regulations Group, FAA, Rotorcraft Directorate. Operators shall submit their requests through an FAA Principal Maintenance Inspector, who may concur or comment and then send it to the Manager, Regulations Group. Note 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Regulations Group. (d) 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 helicopter to a location where the requirements of this AD can be accomplished. (e) This amendment becomes effective on November 30, 1999. Note 4: The subject of this AD is addressed in Transport Canada AD CF-99-04, dated February 24, 1999. Issued in Fort Worth, Texas, on November 3, 1999. Henry A. Armstrong, Manager, Rotorcraft Directorate, Aircraft Certification Service. [FR Doc. 99-29610 Filed 11-12-99; 8:45 am] BILLING CODE 4910-13-U