AD 98-11-15 Airworthiness Directives; Bell Helicopter Textron, Inc. Model 212 Helicopters

Models named: 212. Read the applicability below — it usually turns on serial or part numbers too.

Model 212 helicopters, with tail rotor yoke assembly, part number (P/N) 212-010-704-all dash numbers, P/N 212-010- 744-all dash numbers, or P/N 212-011-702-all dash [[Page 3821]] numbers, 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 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 use the authority provided in paragraph (d) to request approval from the FAA. This approval may address either no action, if the current configuration eliminates the unsafe condition, or different actions necessary to address the unsafe condition described in this AD. Such a request should include an assessment of the effect of the changed configuration on the unsafe condition addressed by this AD. In no case does the presence of any modification, alteration, or repair remove any helicopter from the applicability of this AD.

Required as indicated, unless accomplished previously. To prevent failure of the tail rotor yoke (yoke), loss of the tail rotor, and subsequent loss of control of the helicopter, accomplish the following: (a) Before further flight, review all historical records of the helicopter and the tail rotor yoke assembly (yoke assembly) for any static or dynamic incident history that could have imposed an excessive bending load on the yoke. If such a history exists, comply with paragraph (b) of this AD before further flight. Note 2: Examples of excessive bending loads include exposure to high wind gusts (such as those from rotor wash or prop blast), improper ground handling (in which the tail rotor blade has been used as a hand hold), improper feathering bearing removal (in which the yoke is not properly supported when pressing out bearings), a static ground strike of some type (such as being struck by a vehicle), or an incident in which a damaged tail rotor blade was replaced due to a blade strike. (b) Within the next 180 calendar days, remove the yoke assembly and replace it with an airworthy yoke assembly having zero hours time-in-service (TIS), or with an airworthy yoke assembly (regardless of TIS) that has passed an x-ray diffraction inspection in accordance with Bell Helicopter Textron, Inc. Alert Service Bulletin (ASB) 212-96-100, Revision A, dated May 18, 1998, or ASB 212-96-101, dated September 3, 1996, whichever is applicable. When the yoke assembly is replaced, for helicopters with a yoke assembly, P/N 212-011-702-all dash numbers, install an airworthy tail rotor flapping stop, P/N 212-011-713-103 and for helicopters with yoke assemblies, P/N 212-010-704-all dash numbers or P/N 212-010-744-all dash numbers, install an airworthy trunnion assembly, P/N 212-010- 738-001. If any incident as described in paragraph (a) of this AD occurs after the effective date of this AD and prior to compliance with this paragraph, then compliance with this paragraph is required before further flight. Note 3: Yoke assemblies that have passed an x-ray diffraction inspection at BHTI will have the letters ``FM'' vibro-etched on them following the serial number. (c) After accomplishing the requirements of paragraph (b) of this AD, thereafter, at intervals not to exceed 25 hours TIS, or before further flight after any incident as described in paragraph (a) of this AD, inspect the trunnion assembly and replace the yoke assembly and trunnion assembly, if required, in accordance with Part III, Paragraph 1, of ASB 212-96-100, Revision A, dated May 18, 1998; or inspect the tail rotor flapping stop and replace the yoke assembly and flapping stop, if required, in accordance with Part III, Paragraphs 1, 2, and 3, of ASB 212-96-101, dated September 3, 1996, whichever is applicable. (d) 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, 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, Rotorcraft Certification Office, Rotorcraft Directorate. Note 4: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Rotorcraft Certification Office. (e) 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. (f) The inspection shall be done in accordance with ASB 212-96- 100, Revision A, dated May 18, 1998, or ASB 212-96-101, dated September 3, 1996, whichever is applicable. 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 Bell Helicopter Textron, Inc., P.O. Box 482, Fort Worth, Texas 76101, telephone (817) 280-3391, fax (817) 280-6466. 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. (g) This amendment becomes effective on February 10, 1999, to all persons except those persons to whom it was made immediately effective by Priority Letter AD 98-11-15, issued May 19, 1998, which contained the requirements of this amendment. Issued in Fort Worth, Texas, on January 13, 1999. Eric Bries, Acting Manager, Rotorcraft Directorate, Aircraft Certification Service. [FR Doc. 99-1351 Filed 1-25-99; 8:45 am] BILLING CODE 4910-13-P