Page 5-11
Dec/05
Propeller Owner’s Manual
175
INSPECTION AND CHECK
61-00-75
D. Tachometer Inspection
NOTE:
An appropriately licensed propeller repair facility
may also be able to perform a tachometer
inspection.
WARNING:
OPERATION WITH AN INACCURATE
TACHOMETER MAY RESULT IN
OPERATION AT RESTRICTED RPM AND
DAMAGING HIGH STRESSES. BLADE
LIFE WILL BE SHORTENED AND COULD
RESULT IN CATASTROPHIC FAILURE.
(1) Verify the accuracy of the engine tachometer with a
hand-held tachometer at 100 hour intervals or at annual
inspection, whichever occurs first.
(2) Hartzell Propeller Inc recommends using a tachometer
that is accurate /- 10 RPM, has NIST calibration
(traceable), and has an appropriate calibration schedule.
E. Blade Track
(1) Check the blade track as follows:
(a) Chock the aircraft wheels securely.
(b) Refer to Figure 5-1. Put a fixed reference point
beneath the propeller, within 0.25 inch (6 mm) of the
lowest point of the propeller arc.
NOTE
: This reference point may be a flat board
with a sheet of paper attached to it. The
board may then be blocked up to within
0.25 inch (6.0 mm) of the propeller arc.
WARNING:
MAKE SURE THE ENGINE MAGNETO
IS GROUNDED (OFF) BEFORE
ROTATING THE PROPELLER.
(c) Rotate the propeller by hand (the opposite direction
of normal rotation) until a blade points directly at the
paper. Mark the position of the blade tip in relation to
the paper.
(d) Repeat this procedure with the remaining blades.
(e) Tracking tolerance is + 0.062 inch (1.57 mm) or
0.125 inch (3.17 mm) total.
OBSOLETE PROPELLER MODELS. SEE COVER PAGE
WARNINGS AND SERVICE BULLETIN HC-SB-61-331
