67-10-03 DOWTY-ROTOL PROPELLERS: Amendment 39-570. Applies to Dowty- Rotol Propellers, (c) R.186/4-30-4/16 installed on Armstrong Whitworth Argosy AW-650; (c) R.175/4-30-4/13E installed on Fairchild F-27 and F-27B; (c) R.130/4-20-4/12E installed on Viscount 745D; and (c) R.148/4-20-4/21E installed on Viscount 744.
Amendment 39-382 (32 F.R. 5366), AD 67-10-03, amended by Amendment 39-392 (32 F.R. 5464) is further amended by:
Compliance required as indicated, unless already accomplished.
To prevent failure of the propeller cylinders, P/N's RA.38581, RA.38581/1, RA.44133, RA.44133/1, RA.44709 and RA.62807, due to cracks, accomplish the following:
(a) (1) For (c) R.148/4-20-4/21E propellers with 12,000 or more landings, within the next 10 landings (unless already accomplished within the last 70 landings), and thereafter at intervals not to exceed 80 landings since the last inspection, comply with (b).
(2) For (c) R.186/4-30-4/16, (c) R.175/4-30-4/13E, and (c)R.130/4-20- 4/12E propellers with 12,000 or more landings, within the next 10 landings (unless already accomplished within the last 30 landings), and thereafter at intervals not to exceed 40 landings since the last inspection, comply with (b).
(3) For propellers with 5,900 or more landings but less than 12,000, within the next 100 landings, unless already accomplished within the last 200 landings and thereafter at intervals not to exceed 300 landings since the last inspection, comply with (b).
(4) For propellers with less than 5,900 landings, before accumulating 6,000 landings, and thereafter at intervals not to exceed 300 landings since the last inspection, comply with (b).
(b) Inspect the propeller cylinder retaining nut threads for cracks in accordance with Dowty-Rotol Service Bulletin No. 61-521, Revision 3, dated November 1967, or later ARB- approved revision, using ultrasonic techniques or an equivalent approved by the Chief, Aircraft Certification Staff FAA European Region.
(c) Notwithstanding (a), the repetitive inspection intervals required in (a)(3) and (4) are raised to 600 landings for (c)R.148/4-20-4/21E propellers.
(d) If cracks are found, replace the propeller cylinder before further flight.
(e) For the purposes of determining the total number of landings at which initial compliance with this AD is required, subject to acceptance by the assigned FAA maintenance inspector, the number of landings may be determined by dividing the propeller's hours of time in service by the operator's fleet average time from takeoff to landing for the airplane type.
(f) Cylinders for which number of landings cannot be established must be classed as having above 12,000 landings.
This amendment becomes effective April 1, 1968.