AD 99-17-18 Airworthiness Directives; MD Helicopters, Inc. Model 600N Helicopters

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

Model 600N 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, [[Page 45436]] 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 collective pitch control tubes, collective stick housings, and collective pitch tube assemblies, loss of collective pitch control, and subsequent loss of control of the helicopter, accomplish the following: (a) On or before reaching 400 hours time-in-service (TIS), apply the serial number (S/N) listed in McDonnell Douglas Helicopter Systems Mandatory Service Bulletin No. 600N-009, dated February 24, 1998 (SB), to the two collective stick housings, P/N's 369A7347 and 369A7820; the pilot collective pitch control tube, P/N 369A7348; and the co-pilot collective pitch control tube, P/N 369A7809, in the most visible spot for the specified aircraft S/N. (b) Remove and replace the following flight control components according to the stated life-limits: -------------------------------------------------------------------------------------------------------------------------------------------------------- Life-Limit P/N Component (Hours TIS) -------------------------------------------------------------------------------------------------------------------------------------------------------- 369A7347.................................. Housing, collective stick..................................................................... 450 369A7348.................................. Tube, collective pitch control (pilot)........................................................ 400 369H7354-3................................ Tube assembly, collective pitch (pilot)....................................................... 600 369A7809.................................. Tube, collective pitch control (co-pilot)..................................................... 1,800 369A7820.................................. Housing, collective stick..................................................................... 450 369H7837.................................. Housing, collective stick..................................................................... 450 369H7838-3................................ Tube assembly, collective pitch (co-pilot).................................................... 1,000 -------------------------------------------------------------------------------------------------------------------------------------------------------- (c) Create a component history card or equivalent record in the helicopter log and record the helicopter TIS at installation for each of the components listed in paragraph (b) of this AD. (d) This AD revises the Airworthiness Limitations Section of the maintenance manual by reducing the life-limits of the pilot collective pitch control tube, the collective stick housings, and the collective pitch tube assemblies, and adding the co-pilot collective pitch control tube to the Airworthiness Limitations section, Component Mandatory Replacement Schedule. (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 may be issued in accordance with Secs. 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. (g) The application of serial numbers shall be done in accordance with the Accomplishment Instructions of McDonnell Douglas Helicopter Systems Mandatory Service Bulletin No. 600N-009, dated February 24, 1998. 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, datafax 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 September 24, 1999. Issued in Fort Worth, Texas, on August 12, 1999. Eric Bries, Acting Manager, Rotorcraft Directorate, Aircraft Certification Service. [FR Doc. 99-21572 Filed 8-19-99; 8:45 am] BILLING CODE 4910-13-U