61-05-05 NORTH AMERICAN: Amdt. 260 Part 507 Federal Register March 4, 1961. Applies to All T-28A Aircraft Certified In The Restricted Category. \n\n\tCompliance required as indicated. \n\n\t(a)\tThe R-1300-1A engines which have been overhauled must have Change 53 of T.O. 2R-R1300-5 incorporated upon the accumulation of 860 hours since last overhaul. R-1300-1A engines which have never been overhauled must have Change 53 of T.O. 2R-R1300-5 incorporated upon the accumulation of 860 hours total time in service since new. The modified engines will be designated as R-1300-1B engines by stamping the letter "B" on the engine nameplate. \n\n\t(b)\tThe engine-driven fuel pump, AN-4100, and fuel booster pump must be overhauled every 1,200 hours' time in service. \n\n\t(c)\tThe engine-driven hydraulic pump, AS-6201-1, must be overhauled every 860 hours' time in service. \n\n\t(d)\t(1)\tThe A-422-E1 or -E2 propeller, regardless of serial number, must be disassembled, inspected, and reworked in accordance with T.O. 3H3-3-512 at 300 hours' time in service. \n\n\t\t(2)\tThe A-422-E1 or -E2 propeller must be removed from service after 2,100 hours' time in service. \n\n\t(e)\tConduct an inspection of all cylinders in accordance with paragraph 2 of T.O. 1T-28A-531 at the following intervals: \n\n\t\t(1)\tEvery 30 hours' time in service. \n\n\t\t(2)\tDuring any intermediate engine inspection at which oil leaks, carbon smudges, etc., are detected. \n\n\t(Cylinder assembly P/N 430622 Change T and later changes have shotpeened barrels and do not require the above cylinder barrel inspection. The cylinder assembly number is stamped on the flat of the cylinder identification pad.) \n\n\tThis supersedes AD 58-24-03. \n\n\tThis directive effective March 4, 1961.