AD 93-21-10

93-21-10 BELL HELICOPTER TEXTRON, INC. (BHTI): Amendment 39-8724. Docket Number 91-ASW-18.

Applicability: Model 214B and 214B-1 helicopters, serial numbers (S/N's) 28001 through 28070, equipped with main rotor yoke assembly (assembly), part number (P/N) 214-010-105-001, certificated in any category.

Compliance: Required as indicated, unless accomplished previously.

To prevent failure of the assembly, loss of the main rotor, and subsequent loss of control of the helicopter, accomplish the following:

(a) For assemblies that have 3,700 hours' or less time-in-service on the effective date of this airworthiness directive (AD), replace the assembly on or before reaching 3,750 hours' time-in-service. For assemblies that have more than 3,700 hours' time-in-service on the effective date of this AD, replace the assembly within the next 50 hours' time-in-service.

(b) Within 50 hours' time-in-service after the effective date of this AD, install new airspeed versusaltitude decals, P/N 214-075-256-105 for BHTI Model 214B-1 and P/N 214-075-256-107 for Model 214B helicopters.

(c) Within 50 hours' time-in-service after the effective date of this AD and thereafter at intervals of 1,200 hours' time-in-service, inspect the yoke for straightness in accordance with the applicable maintenance manual.

NOTE: BHTI Alert Service Bulletin No. 214-87-37, Revision A, dated September 10, 1987, pertains to this AD.

(d) An alternative method of compliance or adjustment of the compliance time, which provides an acceptable level of safety, may be used when approved by the Manager, Rotorcraft Certification Office, FAA, Rotorcraft Directorate, Fort Worth, Texas 76193-0170. 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.

NOTE: 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 FAR 21.197 and 21.199 to operate the helicopter to a location where the requirements of this AD can be accomplished.

(f) This amendment becomes effective on January 18, 1994.