Propeller Owner’s Manual
139
INTRODUCTION
61-00-39
Page 1-6
Rev. 17 Apr/20
B.
Engine Modifications
(1)
Engine modifications can affect the propeller. The two
primary categories of engine modifications are those
that affect structure and those which affect power.
An example of a structural engine modification is the
alteration of the crankshaft or damper of a piston engine.
Any change to the weight, stiffness, or tuning of rotating
components could result in a potentially dangerous
resonant condition that is not detectable by the pilot.
Most common engine modifications affect the power
during some phase of operation. Some increase the
maximum power output, while others improve the power
available during hot and high operation (flat rating) or at
off-peak conditions.
(a) Examples of turbine
engine modifications include,
but are not limited to: changes to the compressor,
power turbine or hot section of a turboprop engine.
(b)
Examples of reciprocating engine modifications
include, but are not limited to: the addition or
alteration of a turbocharger or turbonormalizer,
increased compression ratio, increased RPM,
altered ignition timing, electronic ignition, full
authority digital electronic controls (FADEC), or
tuned induction or exhaust.
(2)
All such modifications must be reviewed and approved
by the propeller manufacturer prior to obtaining approval
on the aircraft.
3. Restrictions and Placards
(Rev. 1)
A. Important Information
(1) The propellers covered by this manual may have
a restricted operating range that requires a cockpit
placard.
(a) The restrictions, if present, will vary depending on
the propeller, blade, engine, and/or aircraft model.
(b)
Review the propeller and aircraft type certificate data
sheet (TCDS), Pilot Operating Handbook (POH),
and any applicable Airworthiness Directives for
specific information.
