74-07-03 DOWTY ROTOL: Amendment 39-1803 as amended by Amendment 39-2110. Applies to Dowty Rotol type (c)R 209/4-40-4.5/2, (c)R 245/4-40-4.5/13, and (c)R 259/4-40- 4.5/17 propellers installed on, but not necessarily limited to, Nihon Model YS-11 and YS-11A Series airplanes and Convair Models 600(240D), 640(340D), and 640(440D) Series airplanes equipped with Rolls-Royce Dart Model 542 Series engines.
Compliance is required as indicated.
To prevent possible propeller failure resulting from cracking of full width case hardened rollers in the bottom (C.F.) race of the propeller blade bearings, accomplish the following:
(a) For propellers having blade bearing assemblies that incorporate Modification No. (c) VP2416 (SB61-509) or Modification No. (c) VP2677 (SB61-709) having sets of rollers P/N's 601026724 or 601026940, comply with paragraphs (b) and (c).
(1) Before further flight, after each report of significant propeller induced vibration in flight, except that theairplane may be flown in accordance with FAR Section 21.197 to a base where the repair can be performed; and
(2) If initial compliance is not required by paragraph (a)(1), within the next 600 hours' time in service after the effective date of this AD or before the accumulation of 2,000 hours' time in service on blade bearing bottom (C.F.) race rollers, whichever occurs later.
(b) Replace sets of rollers specified in paragraph (a) in accordance with Dowty Rotol Service Bulletin No. 61-542-8, Revision 2, dated December 20, 1972, for type (c)R 209/4-40- 4.5/2 propellers; Dowty Rotol Service Bulletin No. 61-542-9, dated June 21, 1973, for type (c)R 245/4-40-4.5/13 and (c)R 259/4-40-4.5/17 propellers;
(1) With new parts of the same part number and thereafter continue to replace sets of rollers specified in paragraph (a) in accordance with subparagraph (a)(1) and at intervals not to exceed 2,000 hours' time in service on blade bearing bottom (C.F.) race rollers, and comply with paragraph (c) at each replacement; or
(2) With through hardened sets of rollers which incorporate Modification No. (c) VP2762 (SB61-771) or Modification No. (c) VP2814 (SB61-795).
(c) At each set of roller replacement required by paragraphs (a) and (b), determine the number of broken rollers and the preload in each bearing assembly in accordance with Dowty Rotol Service Bulletin No. 61-542-8, Revision 2, dated December 20, 1972 for type (c)R 209/4- 40-4.5/2 propellers; Dowty Rotol Service Bulletin No. 61-542-9, dated June 21, 1973, for type (c)R 245/4-40-4.5/13 and (c)R 259/4-40-4.5/17 propellers; or an FAA-approved equivalent.
If ten or more rollers are found to be broken or if the preload is found to be less than .0035 inches, before further flight, remove the associated propeller blade, blade retaining bolt, and bearing assembly from service, mark them in a manner that will prevent their further use, and replace them with serviceable parts of the same part numberor FAA-approved equivalents.
(d) The replacement of sets of rollers required by paragraphs (a) and (b) and the inspections required by paragraph (c) may be discontinued when through hardened sets of rollers which incorporate Modification No. (c) VP2762 (SB-771) or Modification No. (c) VP2814 (SB61-795) are installed in accordance with Dowty Rotol Service Bulletin No. 61-542-8, Revision 2, dated December 20, 1972, for type (c)R 209/4-40-4.5/2 propellers; Dowty Rotol Service Bulletin No. 61-542-9, dated June 21, 1973, for type (c)R 245/4-40-4.5/13 and (c)R 259/4-40-4.5/17 propellers; or an FAA-approved equivalent.
Amendment 39-1803 became effective April 19, 1974.
This amendment 39-2110 is effective March 27, 1975.