Maintenance Inspections
Teledyne Continental Motors, Inc.
TM
7-48
IOF-240 Series Engine Maintenance Manual
Change 1
31 August 2007
7-4.
Unscheduled Maintenance
7-4.1. Propeller Strike
A propeller strike is any incident (whether or not the engine is operating) which either
requires repair to a propeller blade (other than minor dressing of the blade) or where the
propeller makes contact with any object that results in the loss of engine RPM.
Propeller strikes against the ground or any object can cause engine and component
damage even though the propeller still may continue to rotate. This damage can result in
catastrophic engine failure.
In cases where a small foreign object such as a small stone, strikes the propeller during
operation, inspect and repair the propeller in accordance with the propeller
manufacturer’s instructions. Any time foreign object damage requires removal of the
propeller for repair(s) other than minor dressing of the blades, adhere to the procedure in
the “Propeller Strike Inspection” section of this manual.
WARNING
Do not attempt to dress a propeller blade without consulting
the propeller manufacturer’s instructions. Stresses imposed on
the propeller are more concentrated in areas that are nicked
and cut that then act as stress risers. Stress risers can weaken
the blade and may eventually cause the blade to fail. If a
propeller blade is lost, the resulting imbalance can cause
separation of the entire engine from the airframe causing the
center of gravity to extend beyond specified limits rendering
the aircraft uncontrollable.
7-4.2. Propeller Strike Inspection
After a propeller strike or in cases where the propeller must be removed for repair, the
complete disassembly and inspection of all engine rotating components is mandatory
and must be accomplished prior to further operation. Perform the inspection as
instructed below:
Procedure
1.
Remove the propeller-repair or replace according to propeller manufacturer’s
instructions.
2.
Disassemble the engine completely according to instructions in the Overhaul Manual
(OH-22).
3.
Perform the Overhaul Inspections in Chapter 9 the Overhaul Manual (OH-22). Use
the Service limits, in Chapter 10 of this manual, rather than the overhaul dimensional
limits during the dimensional inspections.
4.
Inspect all engine accessories in accordance with the manufacturer’s instructions.
5.
Pay particular attention to the crankshaft surfaces forward of the front main bearing
journal. These areas must be free of paint, sludge, or any substance that could mask
reliable magnetic particle testing.