AD 65-05-01 ACTIVE

65-05-01 AERO PRODUCTS: Amdt. 39-42 Part 39 Federal Register March 4, 1965. Applies to Model A6441FN-606 Propeller Blades with Serial Numbers 3999 or below.

Compliance required as indicated.

To detect propeller blade cracks and prevent blade failure, accomplish the following:

(a) When propeller roughness is reported, aircraft shall not be flown, except for evaluation flight to determine cause of propeller roughness, until cause of roughness is corrected. Only essential persons shall be carried during an evaluation flight.

(b) Except as provided in (c), inspect by X-ray the cuff area of blades in accordance with Aero Products Propeller Service Bulletin No. 82 dated October 15, 1959, or later FAA- approved revisions at the following times unless already accomplished:

(1) X-ray blades which had 10,000 or more hours' time in service on January 6, 1965, within 120 hours' time in service after January 6, 1965.

(2) X-ray blades which had 8,000 or more butless than 10,000 hours' time in service on January 6, 1965, within 180 hours' time in service after January 6, 1965.

(3) X-ray blades which had less than 8,000 hours' time in service on January 6, 1965, prior to the accumulation of 8,180 hours' time in service.

(c) The following blades are not required to be initially X-rayed as required by (b) -

(1) Blades shipped from Allison or after December 23, 1964;

(2) Blades which had 10,000 or more hours' time in service on January 6, 1965, that have been magnafluxed externally and internally in the A and B thrust member cavity by any overhaul facility within the last 250 hours' time in service before January 6, 1965;

(3) Blades which had less than 10,000 hours' time in service on January 6, 1965, that have been magnafluxed externally and internally in the A and B thrust, member cavity by any overhaul facility within the last 750 hours' time in service before January 6, 1965; or

(4) Blades which have been modified in accordance with (e).

The repetitive inspections required by (d) for blades 0.150 inch thickness or greater must be accomplished until modified in accordance with (e)(3).

(d) Repeat the X-ray inspection required by (b) for blades with thrust member minimum thickness in the "A" area at last overhaul of 0.150 inch or greater thickness at the following times until modified in accordance with (e):

(1) X-ray blades which had 10,000 or more hours' time in service on January 6, 1965, at intervals not to exceed 250 hours' time in service.

(2) X-ray blades which had 8,000 or more but less than 10,000 hours' time in service on January 6, 1965, at intervals not to exceed 750 hours' time in service until the blade has accumulated 10,000 hours' time in service. Thereafter, X-ray at intervals not to exceed 250 hours' time in service.

(3) X-ray blades which had less than 8,000 hours' time in services on January 6, 1965, at intervals not to exceed 750 hours' time inservice.

(e) Modify the cuff of blades to provide an inspection window in accordance with Allison Commercial Service Letter No. 167, dated February 12, 1965, or later FAA-approved revisions at the following times based on thrust member thickness in the "A" area at last overhaul unless already accomplished:

(1) Modify blades 0.144 inch thickness or less within 100 hours' time in service after the effective date of this AD.

(2) Modify blades 0.145 inch to 0.149 inch thickness within 250 hours' time in service after the effective date of this AD.

(3) Modify blades 0.150 inch thickness or greater within 500 hours' time in service after the effective date of this AD.

(f) Visually inspect the blade shank surface within the cuff window for cracks in accordance with Allison Commercial Service Letter No. 167 or later FAA-approved revisions at the time modification required by (e) is made, and thereafter at intervals not to exceed 25 hours' time in service.

(g) Remove cracked blades from service and report immediately by telephone or telegram to the Chief, Engineering and Manufacturing Branch, FAA Central Region, Kansas City, Missouri.

(h) Remove blades from service according to the following schedule based on thrust member minimum thickness in the "A" area at last overhaul:

(1) Remove from service blades 0.144 inch thickness or less which had 10,000 or more hours' time in service on February 17, 1965; within 50 hours' time in service after February 17, 1965.

(2) Remove from service blades 0.144 inch thickness or less which had less than 10,000 hours' time in service on February 17, 1965, prior to the accumulation of 10,050 hours' time in service.

(3) Remove from service blades 0.145 inch to 0.149 inch thickness which had 12,000 or more hours' time in service on February 17, 1965, within 50 hours' time in service after February 17, 1965.

(4) Remove from service blades 0.145 inch to 0.149 inch thickness which had less than 12,000 hours' time in service on February 17, 1965, prior to the accumulation of 12,050 hours' time in service.

(i) Upon the request of the operator, an FAA maintenance inspector, subject to the prior approval of the Chief, Engineering and Manufacturing Branch, FAA Central Region, may adjust the repetitive intervals specified in this AD to permit compliance at an established inspection period of the operator if the request contains substantiating data to justify the increase for such operator.

NOTE. - "A" area is identified in Allison-Aero-products Overhaul Manual, Section 63-6- 0, Pages 315 and 316.

This supersedes AD 65-01-01.

This directive effective March 4, 1965.