48-43-02 CESSNA and AERONCA: Applies to All Cessna Model 170 and Aeronca Model 15AC Airplanes Equipped With Continental C-145-2 Engines Serial Numbers 3001-8-2 to 3775- 8-2, Inclusive.
Compliance required not later than December 31, 1948.
Some piston pin plugs of the loose fit type with which the engines as noted were originally equipped, are subject to rapid and excessive wear which may eventually cause disintegration of the piston pin plugs, failure of pistons, and complete engine failure due to oil stoppage caused by metal particles on the screen and in the system.
To preclude the possibility of such failures, piston pin and plug assemblies, P/N 25262-A1 (with loose fit plugs), should be removed and replaced with piston pin and plug assemblies, P/N 530830 (with press fit plugs) as soon as possible, and in no case later than the compliance date shown.
Pending installation of the new assemblies, oil screens should be inspected prior to each flight. If aluminumparticles are evident on the screen the airplane should be removed from service until the change is accomplished.
(Continental Service Bulletins Nos. M48-20 and M48-25 cover this same subject.)