AD 2000-22-51 Airworthiness Directives; Model HH-1K, TH-1F, TH-1L, UH-1A, UH-1B, UH-1E, UH-1F, UH-1H, UH-1L, and UH-1P; and Southwest Florida Aviation SW204, SW204HP, SW205, and SW205A-1 Helicopters Manufactured by Bell Helicopter Textron Inc. for the Armed Forces of the United States

Model HH-1K, TH-1F, TH-1L, UH-1A, UH-1B, UH-1E, UH-1F, UH-1H, UH-1L, and UH-1P; and Southwest Florida Aviation SW204, SW204HP, SW205, and SW205A-1 helicopters, manufactured by Bell Helicopter Textron Inc. (BHTI) for the Armed Forces of the United States, with main rotor mast (mast), part number (P/N) 204-011-450-007, -105, or -109, or main rotor trunnion (trunnion), P/N 204-011-105-001, installed, 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.

Required as indicated, unless accomplished previously. Note 2: This AD requires using new factors to recalculate the FACTORED flight hours and the accumulated Retirement Index Number (RIN) for masts installed on certain helicopter models. This AD also expands the serial number (S/N) applicability for the one-time special inspection of the mast. To prevent failure of a mast or trunnion, separation of the main rotor system, and subsequent loss of control of the helicopter, accomplish the following: (a) For the mast, P/N 204-011-450-007, -105, or -109: Note 3: The next higher assembly level for the affected P/N's are the 204-040-366 mast assemblies. Check the aircraft records for the appropriate P/N and assembly level. (1) Within 10 hours time-in-service (TIS), create a component history card or equivalent record for the mast. (2) Within 10 hours TIS, determine and record the accumulated RIN and revised hours TIS for the mast as follows: (i) Review the aircraft maintenance records for the mast. If the helicopter model installation history or hours TIS of the mast is unknown, remove the mast from service, identify the mast as unairworthy, and replace it with an airworthy mast before further flight. (ii) Determine the accumulated RIN and the revised hours TIS in accordance with the Instructions in Appendix 1. For those hours TIS the mast has been installed on a BHTI Model 204B, 205A, 205A-1, 205B, or 212 helicopter, determine the accumulated RIN in accordance with the AD's issued for those helicopters. (iii) Record the accumulated RIN and revised hours TIS for the mast on the component history card or equivalent record. Use the revised hours TIS as the new hours TIS for the mast. (3) Before further flight after accomplishing the requirements of paragraph (a)(2) of this AD, remove from service any mast that has accumulated 265,000 or more RIN or 15,000 or more revised hours TIS and identify the mast as unairworthy. Replace the mast with an airworthy mast. (4) Within 25 hours TIS, remove any hub spring installed on any affected helicopter. Note 4: U.S. Army Modification Work Order (MWO) 55-1520-242-50-1 pertains to the removal of the hub spring and replacement of any required parts. U.S. Army Safety of Flight Message UH-1-00-10 dated July 19, 2000, also pertains to the subject of this AD. (5) Determine whether a mast with S/N 00000 through 52720, 61433 through 61444, or 61457 through 61465 (regardless of prefix), has ever been installed on a helicopter while operated with a hub spring. (i) If a mast has never been installed on a helicopter while operated with a hub spring, before reaching 100,000 RIN, inspect the upper and lower snap ring grooves in the damper clamp splined area for: (A) A minimum radius of 0.020 inch around the entire circumference (see Figures 1 and 2), using a 100 × or higher magnification. If any snap ring groove radius is less than 0.020 inch, identify the mast as unairworthy and replace it with an airworthy mast before exceeding 100,000 RIN. (B) A burr (see Figures 1 through 3), using a 200 × or higher magnification. If a burr is found in any snap ring groove/spline intersection, identify the mast as unairworthy and replace it with an airworthy mast before exceeding 170,000 RIN. (ii) If a mast has ever been installed on a helicopter while operated with a hub spring or if the history of a hub spring installation is unknown, before reaching 100,000 RIN or 400 unfactored flight hours, whichever occurs first, inspect the upper and lower snap ring grooves in the damper clamp splined area for: (A) A minimum radius of 0.020 inch around the entire circumference (see Figures 1 and 2), using a 100 × or higher magnification. If any snap ring groove radius is less than 0.020 inch, identify the mast as unairworthy and replace it with an airworthy mast before further flight. (B) A burr (see Figures 1 through 3), using a 200 × or higher magnification. If a burr is found in any snap ring groove/spline intersection, identify the mast as unairworthy and replace it with an airworthy mast before further flight. (6) After accomplishing the requirements of paragraph (a)(2) of this AD, continue to calculate the accumulated RIN for the mast by multiplying all takeoff and external load lifts by the RIN factors defined in columns (D) and (G) of Table 1 of Appendix 1 of this AD. (7) After accomplishing the requirements of paragraph (a)(2) of this AD, continue to count the hours TIS for the mast. Any hours TIS for the mast while installed on a helicopter operated with a hub spring or if the history of a hub spring installation is unknown must be factored in accordance with the instructions in Appendix 1 of this AD. (8) This AD establishes a retirement life of 265,000 accumulated RIN or 15,000 hours TIS, whichever occurs first, for mast, P/N 204-011-450-007, -105, and -109. (9) Within 10 days after completing the inspections required by paragraph (a)(5) of this AD, send the information contained on the AD compliance inspection report sample format contained in Appendix 2 to the Manager, Rotorcraft Certification Office, Federal Aviation Administration, Fort Worth, Texas 76193-0170, USA. Reporting requirements have been approved by the Office of Management and Budget and assigned OMB control number 2120-0056. BILLING CODE 4910-13-P ER11DE00.000 ER11DE00.001 ER11DE00.002 BILLING CODE 4910-13-C (b) For the trunnion, P/N 204-011-105-001: (1) Within 10 days, create a component history card or equivalent record for the trunnion and record the hours TIS accumulated on the trunnion. If the TIS cannot be determined, enter 900 hours for each year from the date the trunnion was installed. (2) Remove any trunnion with 14,900 or more hours TIS from service within the next 100 hours TIS. (3) Remove any trunnion with less than 14,900 hours TIS from service at or before 15,000 hours TIS. Note 5: Paragraph (b) of this AD continues the requirements of the superseded AD for the trunnion. (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, Rotorcraft Certification Office, FAA. Operators shall submit their request through an FAA Principal Maintenance Inspector, who may concur or comment and then send it to the Manager, Rotorcraft Certification Office. Note 6: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Manager, Rotorcraft Certification Office. (d) Special flight permits may be issued in accordance with 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 December 26, 2000, to all persons except those persons to whom it was made immediately effective by Emergency AD 2000-22-51, issued November 2, 2000, which contained the requirements of this amendment. BILLING CODE 4910-13-P APPENDIX 1 ER11DE00.003 ER11DE00.004 ER11DE00.005 ER11DE00.006 ER11DE00.007 ER11DE00.008 ER11DE00.009 ER11DE00.010 ER11DE00.011 ER11DE00.012 ER11DE00.013 BILLING CODE 4910-13-C Appendix 2 Appendix 2 to AD 2000-22-51 AD Compliance Inspection Report (Sample Format) P/N 204-011-450-007/-105/-109 Main Rotor Mast Provide the following information and mail or fax it to: Manager, Rotorcraft Certification Office, Federal Aviation Administration, Fort Worth, Texas 76193-0170, USA, Fax: 817-222-5783. Aircraft Registration No: Helicopter Model: Helicopter S/N: Mast P/N: Mast S/N: Mast RIN: Mast Total TIS: Inspection Results Were any radii during inspection of this mast determined to be less than 0.020 inch? If yes, what was the dimension measured? Was a burr found in the inspected snap ring grooves? Were cracks noted during the inspection? Who performed this inspection? Provide any other comments? Issued in Fort Worth, Texas, on November 30, 2000. Larry M. Kelly, Acting Manager, Rotorcraft Directorate, Aircraft Certification Service. [FR Doc. 00-31012 Filed 12-8-00; 8:45 am] BILLING CODE 4910-13-P