AD 80-17-05

80-17-05 BELL: Amendment 39-3875. Applies to Models 206A, 206B, 206A-1, 206B-1, and 206L helicopters equipped with tail rotor blades, P/N 206-010-750-005 and -007, certificated in all categories (Airworthiness Docket No. 80-ASW-18).

Compliance required as indicated.

To prevent possible failure of tail rotor blades, P/N 206-010-750-005 and -007, due to fatigue cracks, accomplish the following:

a. Before the first flight of each day after the effective date of this AD, visually check for chordwise cracks in the tail rotor blade skin surfaces in the area between Blade Station 7.1 and 11.1 using a three-power or higher magnifying glass. (Blade Station 0 is the center of the tail rotor yoke.)

b. Replace tail rotor blades having cracks before further flight.

c. Blades with 450 or more hours' time in service (as calculated in paragraph (e) below) on the effective date of this AD must be removed from service within the next 50 hours' time in service.

d. Blades with less than 450 hours' time in service (as calculated in paragraph (e) below) on the effective date of this AD must be removed from service prior to or on attaining 500 hours' time in service.

e. For purposes of this AD, hours' time in service is calculated by the following formula:

Time on 206A/B Series + Time on 206L = Calculated Time in Service 2.4

f. The check required by paragraph (a) of this AD may be performed by the pilot, providing the pilot's logbook has been endorsed by a properly rated mechanic stating that the pilot has been trained to conduct the daily check in accordance with this AD.

NOTE: For the requirements regarding the listing of compliance with this AD in the aircraft maintenance record, see FAR 91.173.

(Bell Helicopter Textron Operations Safety Notice No. 206-79-5/206L-79-2, dated December 4, 1979; Alert Service Bulletin Nos. 206-80-6 dated February 22, 1980, and 206L-80- 8, Rev. A, dated June 3, 1980; and Technical Bulletin Nos. 206-78-3 dated July 18, 1978, and 206L-79-38 dated September 28, 1979, pertain to this subject.)

This amendment becomes effective September 10, 1980.