AD 99-25-08 Airworthiness Directives; MD Helicopters Inc. Model 500N and 600N Helicopters

Models named: 500N, 600N. Read the applicability below — it usually turns on serial or part numbers too.

Model 500N helicopters, serial numbers (S/N) 001 through 099 with a prefix of “LN”, and Model 600N helicopters, S/N 003 through 074 with a prefix of “RN”, 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 (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 failure of the thruster control cable conduit cap (cap) at the telescopic swivel end or relieved area and subsequent loss of normal anti-torque directional control of the helicopter, accomplish the following: (a) Within 5 hours time-in-service (TIS) or before further flight after December 31, 1999, whichever occurs first, inspect the forward and center thruster control cables, part number (P/N) 500N7201-5, -7, -37, -45, or -51, installed in affected helicopters, for a crack, corrosion, or damage in the cap at the telescopic swivel end in accordance with the following paragraphs of the Accomplishment Instructions, Section 2, of MD Helicopters Inc. (MDHI) Service Bulletin SB500N-021 SB600N-028, dated November 19, 1999 (SB 021/028). (1) Inspect the forward thruster control cables in accordance with paragraphs A.(1) through (5) of SB 021/028. Install safety wire in accordance with paragraph A.(7) of SB 021/028. (2) Inspect the center thruster control cable in accordance with paragraphs B.(1) through (4) and (6) of SB 021/028. (3) If an unacceptable crack or ball separation from the cap is found, remove and replace the unairworthy forward or center thruster control cable with an airworthy cable prior to further flight. (b) Within 100 hours TIS or before further flight after February 19, 2000, whichever occurs first, inspect the forward and center thruster control cables, P/N 500N7201-5, -7, -37, -45, or -51, installed in affected helicopters in the cap relieved area for a crack, corrosion, or damage in accordance with the Accomplishment Instructions, Section 2, of MDHI SB SB500N-020R1 SB600N-027R1, dated November 24, 1999 (SB 020/027). (1) Inspect the forward thruster control cable for a crack or corrosion in accordance with paragraphs B.(1) through (5) and (7) of SB 020/027. (2) Inspect the center thruster control cable for a crack or corrosion in accordance with paragraphs C.(1) through (4), (6), and (for Model 600N only) (7) of SB 020/027. (3) If an unacceptable crack is found, remove and replace the unairworthy forward or center thruster control cable with an airworthy cable prior to further flight. (c) Repeat the inspections of paragraphs (a) and (b) of this AD at intervals not to exceed 100 hours TIS or 3 calendar months, whichever occurs first. (d) On or before December 1, 2000, replace the forward and center thruster control cables, part number (P/N) 500N7201-5, -7, -37, and -45, and -51, with P/N 500N7201-55 and -57 on the MDHI Model 500N or P/N 500N7201-55 and -59 on the MDHI Model 600N. Accomplishment of the requirements of this paragraph is terminating action for the requirements of 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, 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 2: 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. (f) Special flight permits will not be issued. (g)(1) The inspections required within 5 hours time-in-service or before further flight after December 31, 1999, whichever occurs first, shall be done in accordance with the following paragraphs of the Accomplishment Instructions, Section 2, of MD Helicopters Inc. Service Bulletin SB500N-021 SB600N-028, dated November 19, 1999: (i) Paragraphs A.(1) through (5); (ii) Paragraph A.(7); (iii) Paragraphs B.(1) through (4) and (6). (2) The inspections required within 100 hours time-in-service shall be done in accordance with the following paragraphs of the Accomplishment Instructions, Section 2, of MDHI SB SB500N-020R1 SB600N-027R1, dated November 24, 1999: (i) Paragraphs B.(1) through (5) and (7); (ii) Paragraphs C.(1) through (4), (6), and (for Model 600N only) (7). (3) 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 MD Helicopters Inc., Attn: Customer Support Division, 5000 E. McDowell Rd., Mail Stop M615-GO48, Mesa, Arizona 85215-9797, telephone 1-800-388-3378 or 480-891-6342, fax 480-891-6782. Copies may be inspected at the FAA, Office of the Regional Counsel, Southwest Region, 2601 Meacham Blvd., Room 663, Fort Worth, Texas; or at the Office of the Federal Register , 800 North Capitol Street, NW., suite 700, Washington, DC. (h) This amendment becomes effective on March 1, 2000, to all persons except those persons to whom it was made immediately effective by Emergency Priority Letter AD 99-25-08, issued November 26, 1999, which contained the requirements of this amendment. Issued in Fort Worth, Texas, on February 7, 2000. Henry A. Armstrong, Manager, Rotorcraft Directorate, Aircraft Certification Service. [FR Doc. 00-3222 Filed 2-14-00; 8:45 am] BILLING CODE 4910-13-U