64-13-02 FAIRCHILD: Amdt. 735 Part 507 Federal Register May 23, 1964. Applies to all Model F-27 Series Aircraft with Dowty Main Landing Gear Outer Cylinders P/N's 9010Y3, 9017Y1, 200020.609, 2.00021.241, 200021.276, 200042.302, 2.00042.303, 2.00042.601, and 2.00042.618.
Compliance required as indicated.
Due to failures of main landing gear outer cylinder torque link attach lugs, to which the upper torque link, Dowty P/N C9027Y3 is attached, the following measures are required:
(a) Outer cylinders which have accumulated 8,000 or more landings as of the effective date of this AD, but have not been modified in accordance with either Fairchild Service Bulletin No. 32-41A dated April 5, 1961, or Dowty Service Bulletins No. 32-15 dated October 1961, or No. 32-11 issued August 1961, revised December 1962, or equivalent approved by the Chief, Engineering and Manufacturing Branch, FAA Eastern Region, must be inspected as follows:
(1) Conduct a daily visual inspection for cracks in the vertical radii on the inboard and outboard sides of the main cylinder lug.
(2) Inspect the area specified in (a)(1) using dye penetrant method or FAA approved equivalent inspection within the next 50 landings after the effective date of this AD, unless already accomplished within the last 250 landings, and every 300 landings after such inspection.
(3) If cracks are found the following shall be accomplished:
(i) A crack that can be removed by reworking the outer cylinder in accordance with Fairchild Service Bulletin No. 32-41A dated April 5, 1961, or Dowty Service Bulletins No. 32-15 dated October 1961, or No. 32-11 issued August 1961, revised December 1962, or equivalent approved by the Chief, Engineering and Manufacturing Branch, FAA Eastern Region, must be removed before further flight.
(ii) If the crack cannot be removed as specified in (a)(3)(i), that cylinder must be replaced before further flight.
(b) Outer cylinders modified in accordance with Fairchild Service Bulletin No. 32- 41A dated April 5, 1961, or equivalent approved by the Chief, Engineering and Manufacturing Branch, FAA Eastern Region, must be inspected as follows:
(1) Conduct a daily visual inspection for cracks in the vertical radii on the inboard and outboard sides of the main cylinder lug.
(2) Inspect the area specified in (b)(1) using dye penetrant method of FAA approved equivalent inspection within the next 50 landings after the effective date of this AD unless already accomplished within the last 250 landings, and every 300 landings after such inspection.
(3) If cracks are found the following shall be accomplished:
(i) A crack that can be removed by reworking the outer cylinder in accordance with Dowty Service Bulletins No. 32-15 dated October 1961, or equivalent approved by the Chief, Engineering and Manufacturing Branch, FAA Eastern Region, must be removed before further flight.
(ii) If the crack cannot be removed as specified in (b)(3)(i), that cylinder must be replaced before further flight.
(c) Outer cylinders modified in accordance with Dowty Service Bulletin No. 32-15 dated October 1961, or equivalent approved by the Chief, Engineering and Manufacturing Branch, FAA Eastern Region, must be inspected as follows:
(1) Conduct a daily visual inspection for cracks in the vertical radii on the inboard and outboard sides of the main cylinder lug.
(2) Inspect the area specified in (c)(1) using dye penetrant method or FAA approved equivalent inspection within the next 50 landings after the effective date of this AD unless already accomplished within the last 250 landings, and every 300 landings after such inspection.
(3) If cracks are found, that cylinder must be replaced before further flight.
(d) Outer cylinders modified after the accumulation of 7,000 landings, in accordance with Dowty Service Bulletin No. 32-11 issued August 1961, revised December 1962, or equivalent approved by the Chief, Engineering and Manufacturing Branch, FAA Eastern Region, must be inspected as follows:
(1) Conduct a daily visual inspection for cracks in the vertical radii on the inboard and outboard sides of the main cylinder lug.
(2) Inspect the area specified in (d)(1) using dye penetrant method or FAA approved equivalent inspection within the next 50 landings after the effective date of this AD unless already accomplished within the last 650 landings, and every 700 landings after such inspection.
(3) If cracks are found, that cylinder must be replaced before further flight.
(e) Outer cylinders modified prior to the accumulation of 7,000 landings in accordance with Dowty Service Bulletin No. 32-11 issued August 1961, revised December 1962, or equivalent approved by the Chief, Engineering and Manufacturing Branch, FAA Eastern Region, are not required to be inspected under this AD.
(f) Where past records of landings have not been maintained or are unavailable, the number of landings prior to the effective date of this AD shall be estimated by substituting two (2) landings for each hour of time in service. Where the operator does not desire to keep a record of landings, the number of landings shall be estimated by substituting two (2) landings for each hour of time in service.
(g) Compliance inspection times and affectivity paragraphs, specified in the service bulletins discussed herein, must be disregarded.
(h) Upon request of the operator, an FAA maintenance inspector, subject to prior approval of the Chief, Engineering and Manufacturing Branch, FAA Eastern Region, may adjust the repetitive inspection 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.
This supersedes AD 61-10-03.
This directive effective June 26, 1964.