53-09-01: Link Pins

53-09-01 PRATT & WHITNEY: Applies to R-2000 Series Engines Overhauled by San Antonio Air Depot Between July 1, 1952, and April 9, 1953. Compliance required prior to further carriage of passengers or cargo in aircraft with such engines installed. Aircraft may be ferried to base where inspection is to be conducted. Several operators of C-54 aircraft utilizing military overhauled engines, have experienced failures of link (knuckle) pins in the subject engines due to improper overhaul, inspection, or assembly procedures. The failures have occurred in comparatively low-time engines, and cracked pins have been found in engines with zero TSO. To preclude the possibility of further failures of this nature, engines falling within the category as noted must be dissassembled and the link pins magnetically inspected, eliminating any found with cracks, then reassembled in accordance with manufacturer's instructions, prior to further flight. Date of overhaul and identification ofoverhaul base stamped on exterior surface of engine nose housings.