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YO-233-B2A Engine Maintenance Manual
TEO-540-A1A Engine Maintenance Manual
J. Metal Contamination of the Lubrication System
(1) If metallic particles/residue, metal shavings or metal flakes is found in the engine oil after
oil servicing, refer to the "Identification of Metallic Solids After Oil Servicing" section in
Chapter 12-10 and complete the recommended corrective action.
K. Propeller Strike, Sudden Engine Stoppage or Loss of a Propeller Blade Tip
(1) This section includes recommendations for aircraft engines that have had propeller/rotor
damage as well as any of the following.
— Separation of the propeller/rotor blade from the hub
— Loss of a propeller or rotor blade tip
— Sudden stoppage after accidental propeller/rotor damage.
(2) A propeller strike includes:
— Any incident, whether or not the engine is operating, where repair of the propeller is
necessary
— Any incident during engine operation where the propeller has impact on a solid object
which causes a decrease in rpm and also makes a structural repair of the propeller
necessary. This incident includes propeller strikes against the ground. Although the
propeller can continue to rotate, damage to the engine can occur, possibly with
progression to engine failure
— Sudden rpm drop on impact to water, tall grass, or similar yielding medium where
propeller damage does not usually occur.
(3) A propeller strike can occur at taxi speeds, including instances of touch and go operations
with propeller tip ground contact. In addition, propeller strikes also include situations
where an aircraft is stationary and a landing gear collapse occurs causing one or more
blades to be bent, or where a hangar door (or other object) hits the propeller blade. These
instances are cases of sudden engine stoppage because of potentially severe side loading
on the crankshaft flange, front bearing, and seal.
(4) Recommended Corrective Action for Propeller Strikes
(a) Circumstances of a propeller strike cannot always be used as predictors for the extent
of engine damage or its future reliability. There can be varying degrees of damage to
an engine and propeller from a propeller strike. The initial damage can be hidden but
becomes progressive and worsens with time and wear.
© 2021 Avco Corporation. All Rights Reserved
February 2021
BASED UPON THE ACCUMULATED ENGINEERING, TECHNICAL
AND HISTORICAL DATA AVAILABLE, LYCOMING ENGINES
PROHIBITS STRAIGHTENING OR GRINDING OF BENT
CRANKSHAFT FLANGES TO RESTORE MAXIMUM RUN-OUT
SPECIFICATION AS NOTED IN THE LATEST REVISION OF SSP-
1776, TABLE OF LIMITS. IF THE CRANKSHAFT FLANGE IS BENT,
REPLACE THE CRANKSHAFT. DO NOT TRY TO STRAIGHTEN
OR GRIND THE CRANKSHAFT FLANGE.
DAMAGE TO A PROPELLER IS SERIOUS AND CAN CAUSE THE
ENGINE TO BE UNAIRWORTHY.
05-50
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