AD 84-10-51 R1

84-10-51 R1 BOEING VERTOL COMPANY: Amendment 39-5024 as amended by Amendment 39-5352. Applies to Model 234 series helicopters, certificated in any category, equipped with forward main rotor drive shaft P/N 114D1245-7.

Compliance is required as indicated, unless already accomplished.

To prevent possible hazards in flight associated with cracking of the forward main rotor drive shaft, accomplish the following:

(a) Within 70 hours time in service after the effective date of this amendment or upon accumulation of 1,600 total hours time in service on the rotor shaft, whichever occurs later, and thereafter at intervals not to exceed 35 hours time in service from the last inspection, inspect the rotor drive shaft in accordance with paragraph 3, "Accomplishment Instructions," Boeing Vertol Service Bulletin No. 234-63-1009, dated June 29, 1984, or Revision 1 dated May 1, 1986, or an FAA-approved equivalent.

(b) Remove from service forward main rotor drive shafts havinga crack and replace with a serviceable part prior to further flight.

(c) An equivalent method of compliance with this AD may be used when approved by the Manager, New York Aircraft Certification Office, 181 South Franklin Avenue, Room 202, Valley Stream, New York 11581.

(d) Upon submission of substantiating data by an owner through an FAA Maintenance Inspector, the Manager, New York Aircraft Certification Office, FAA New England Region, may adjust the compliance times specified in this AD.

(e) The manufacturer's specifications and procedures identified and described in this directive are incorporated herein and made a part hereof pursuant to 5 U.S.C. 552(a)(1). All persons affected by this directive who have not already received these documents from the manufacturer may obtain copies upon request to the Boeing Vertol Company, Boeing Center, P.O. Box 16858, Philadelphia, Pennsylvania 19142. These documents may also be examined at the Office of the Regional Counsel, Southwest Region, Federal Aviation Administration, 4400 Blue Mound Road, Fort Worth, Texas.

Amendment 39-5024 (50 FR 15539) became effective April 22, 1985, as to all persons except those persons to whom it was made immediately effective by telegraphic AD No. T84-10- 51, issued May 3, 1984, which contained this amendment.

This Amendment 39-5352 becomes effective July 24, 1986.