AD 2001-24-51 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, serial numbers with a prefix “RN” and 003 through 063, 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. To prevent failure of a tailboom attachment, loss of the tailboom, and subsequent loss of control of the helicopter, accomplish the following: (a) Within 5 hours time-in-service (TIS): (1) Remove the tailboom fairing and tailboom. Remove both upper tailboom attachment access covers in accordance with the Accomplishment Instructions, paragraph 2.B.(2) of MD Helicopters, Inc. (MDHI) Service Bulletin SB600N-036, dated November 2, 2001 (SB). Note 2: MDHI CSP-HMI-2, Section 53-40-30, pertains to the subject of this AD. (2) Using a light and a 10x or higher magnifying glass: (i) Inspect the right and left upper tailboom attachments, part number (P/N) 500N3422 and 500N3422-3, respectively, for a crack as shown in Figure 1 of the SB. If a crack is found, replace any cracked attachment fitting with an airworthy attachment fitting before further flight. (ii) Inspect both upper tailboom attachment nutplates for thread damage or a crack. Replace any damaged or cracked nutplate with an airworthy nutplate before further flight. (iii) Inspect both angles for a crack. If a crack is found on a right-hand angle, P/N 500N3429-6, before further flight, install a new clip in accordance with the Accomplishment Instructions, paragraph 2.B.(5)(c) of the SB. If a crack is found on the left-hand angle, P/N 500N3429-7, before further flight, replace the angle with an airworthy angle, or repair the angle in accordance with FAA-approved procedures. (3) Replace the upper right-hand (pilot side) tailboom attachment bolt (bolt) with a new bolt. (4) If the removed upper pilot-side bolt is found broken, replace the remaining three bolts with airworthy bolts before further flight. (5) Add one washer, P/N AN960C516 (NAS1149C0563R) or AN960C616 (NAS1149C0663R), as appropriate, to each tailboom bolt between the tailboom and the NAS1587 countersunk washer. A minimum of two threads must extend past the nutplate. (6) Modify both access covers in accordance with the Accomplishment Instructions, paragraph 2.B.(6), of the SB. (b) At intervals not to exceed 25 hours TIS, using a borescope, through the hole in each upper access cover, inspect the right and left upper tailboom attachments, nutplates, and angles for a crack. If a crack is found, replace or repair any cracked part with an airworthy part in accordance with the requirements of this AD before further flight. (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, Los Angeles Aircraft Certification Office (LAACO), FAA. Operators shall submit their requests through an FAA Principal Maintenance Inspector, who may concur or comment and then send it to the Manager, LAACO. Note 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the LAACO. (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) The removal of the upper tailboom attachment access covers, inspection of the tailboom attachments, installation of a new clip, and modification of the access covers shall be accomplished in accordance with the Accomplishment Instructions, paragraphs 2.B.(2), 2.B.(5)(c), 2.B.(6), and Figure 1, of MD Helicopters, Inc. Service Bulletin SB600N-036, dated November 2, 2001. 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, 4555 E. McDowell Rd., Mail Stop M615-GO48, Mesa, Arizona 85215-9734, telephone 1-800-388-3378, fax 480-891-6782, or on the web at www.mdhelicopters.com. 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. (f) This amendment becomes effective on April 29, 2002, to all persons except those persons to whom it was made immediately effective by Emergency AD 2001-24-51, issued November 28, 2001, which contained the requirements of this amendment. Issued in Fort Worth, Texas, on April 2, 2002. Eric Bries, Acting Manager, Rotorcraft Directorate, Aircraft Certification Service. [FR Doc. 02-8595 Filed 4-11-02; 8:45 am] BILLING CODE 4910-13-P