AD 80-10-02

80-10-02 MESSERSCHMITT-BOLKOW-BLOHM: Amendment 39-3765. Applies to Model BO-105 series helicopters with tail rotor blade grip P/N 105-31711 or P/N 105-31722 installed, certificated in any category.

To prevent failure of the tail rotor system, accomplish the following:

(a) Within the next 10 hours time in service after the effective date of this AD, unless already accomplished within the last 90 hours time in service, and thereafter at intervals not to exceed 100 hours time in service from the last inspection, inspect the visible part of the inner surface of the tail rotor blade grip clevis area (do not remove blade retaining bolt bushings) for cracks using the dye penetrant method in accordance with Messerschmitt-Bolkow-Blohm BO- 105 Alert Service Bulletin No. 18 dated March 15, 1979, or an FAA-approved equivalent.

(b) Within the next 100 hours after installing a replacement tail rotor blade grip in accordance with paragraph (g) of this AD, and thereafter at intervals not to exceed 100 hours time in service from the last inspection, inspect the visible part of the inner surface of the tail rotor blade grip clevis area (do not remove blade retaining bolt bushings) for cracks using the dye penetrant method in accordance with Messerschmitt-Bolkow-Blohm BO-105 Alert Service Bulletin No. 18 dated March 15, 1979, or an FAA-approved equivalent.

(c) Within the next 100 hours time in service after the effective date of this AD -

(1) Visually inspect the inboard end of the tail rotor blade grip for cracks in accordance with paragraph 2.A.1 "Accomplishment Instructions" of Messerschmitt-Bolkow- Blohm Service Bulletin 30-24 dated December 1, 1978, or an FAA-approved equivalent; and

(2) Inspect the tail rotor blade grip in the vicinity of the bore of the laminated pack retaining bolt (on the inner side) for cracks using the dye penetrant method in accordance with paragraph 2.A.2 "Accomplishment Instructions" of Messerschmitt-Bolkow- Blohm BO-105 Service Bulletin 30-24 dated December 1, 1978, or an FAA-approved equivalent.

(d) Within the next 100 hours time in service after accomplishing the inspection required by paragraph (c)(1) of this AD or installing a replacement tail rotor blade grip in accordance with paragraph (g) of this AD, and thereafter at intervals not to exceed 100 hours time in service from the last inspection, visually inspect the inboard end of the tail rotor blade grip for cracks in accordance with "Special Inspections." Chapter 10 of the Messerschmitt-Bolkow- Blohm BO-105 Maintenance and Overhaul Manual or an FAA-approved equivalent.

(e) Within the next 600 hours time in service after accomplishing the inspection required by paragraph (c)(2) of this AD or installing a replacement tail rotor blade grip in accordance with paragraph (g) of this AD, and thereafter at intervals not to exceed 600 hours from the last inspection, inspect the tail rotor blade grip in the vicinity of the bore of the laminated pack retaining bolt (on the inner side) for cracks using the dye penetrant method in accordance with "Special Inspections," Chapter 10, of the Messerschmitt-Bolkow-Blohm BO-105 Maintenance and Overhaul Manual or an FAA-approved equivalent.

(f) If, during any inspection required by this AD, any cracks are found, before further flight, replace the cracked tail rotor blade grip in accordance with paragraph (g) of this AD.

(g) For all replacement tail rotor blade grips installed after the effective date of this AD -

(1) Use a new or used crack-free tail rotor blade grip of the same part number. Before installation of a used tail rotor blade grip, inspect the part using the dye penetrant method to ensure that it is crack-free; and

(2) Comply with the repetitive inspection requirements of paragraphs (b), (d), and (e) of this AD.

NOTE: This AD applies to both tail rotor blade grips installed on the helicopter.

This amendment becomes effective May 1, 1980, as to all persons except those persons to whom it was made immediately effective by the telegram dated March 30, 1979, which contained this amendment.