Hartzell HC-D2MV20-3 Series Owner's Manual And Logbook page 5

inspection of the propeller. Experimental installations often
use propeller-engine combinations that have not been
tested and approved. In these cases, the stress on the
propeller and, therefore, its safety margin is unknown.
Failure could be as severe as loss of propeller or propeller
blades and cause loss of propeller control and/or loss of
aircraft control.
Hartzell Propeller Inc. follows FAA regulations for propeller
certification on certificated aircraft. Experimental aircraft
may operate with unapproved engines or propellers or
engine modifications to increase horsepower, such as
unapproved crankshaft damper configurations or high
compression pistons. These issues affect the vibration
output of the engine and the stress levels on the propeller.
Significant propeller life reduction and failure are real
possibilities.
Frequent inspections are strongly recommended if
operating with a non-certificated installation; however, these
inspections may not guarantee propeller reliability, as a
failing device may be hidden from the view of the inspector.
Propeller overhaul is strongly recommended to accomplish
periodic internal inspection.
Visually inspect metal blades for cracks. Inspect hubs,
with particular emphasis on each blade arm for cracks.
Eddy current equipment is recommended for hub
inspection, since cracks are usually not apparent.
Propeller Owner's Manual
140
MESSAGE
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Nov/02