AD 92-06-12

92-06-12 BELL HELICOPTER TEXTRON, INC.: Amendment 39-8192. Docket No. 90-ASW-48.

Applicability: All Model 206A, 206B, 206L, 206L-1, and 206L-3 helicopters, certificated in any category, with the main transmission sungear, part number (P/N) 206-040-662-101, installed.

Compliance: Required as indicated, unless already accomplished.

To prevent premature wear of the sungear and mating spur gears which could result in transmission failure, accomplish the following:

(a) At the next inspection interval for the main transmission sungear, P/N 206-040-662-101, but no later than 1,500 hours' time in service after the effective date of this AD, remove and replace sungears which have the following serial numbers:

SD-0005 SD-0010 SD-0020 SD-0022 SD-0023 SD-0024 SD-0025 SD-0026 SD-0027 SD-0031 SD-0033 SD-0034 SD-0035 SD-0036 SD-0037 SD-0039 SD-0040 SD-0043 SD-0044 SD-0046 SD-0054 SD-0055 SD-0057 SD-0060 SD-0062 SD-0065 SD-0066 SD-0067 SD-0068 SD-0069 SD-0071

(b) In conjunction with (a), inspect the pinion spur gears which mate with the above listed sungears for micro pitting or hardlines in the gear teeth due to the insufficient tip relief, or improper tooth profile of the sungear. Determine if wear or damage is within specified limits according to the applicable BHTI maintenance, repair and overhaul manuals.

(c) If wear or damage exceeds the specified limits, remove and replace the affected spur gears with serviceable parts before further flight.

(d) An alternative method of compliance or adjustment of the compliance times which provides an acceptable level of safety may be used if approved by the Manager, Rotorcraft Certification Office, ASW-170, Rotorcraft Directorate, Aircraft Certification Service, FAA, Fort Worth, Texas, 76193-0170.

(e) Bell Helicopter Textron, Inc., Alert Service Bulletins No. 206-90-56, Rev. A, dated 1/15/91 or 206L-90-69, Rev. A, dated 1/15/91, as applicable, provide an acceptable, alternate means of compliance with this AD.

(f) This amendment becomes effective on April 13, 1992.