FAA Advisory Circular 43.13-1B
Acceptable Methods, Techniques, and Practices
Aircraft Inspection and Repair
AC 43.13-1B | 8. Engines, Fuel, Exhaust, and Propellers | 6. Propeller Tracking and Vibration | 8-107. General
9/8/98
SECTION 6. PROPELLER TRACKING AND VIBRATION AC 43.13-1B
8-107. GENERAL. To ensure smooth
powerplant operations, first start with a prop-
erly-installed propeller. Each propeller should
be checked for proper tracking (blades rotating
in the same plane of rotation). Manufacturer’s
recommendations should in all cases be
followed.
8-108. PROPELLER TRACKING
CHECK. The following is a simple procedure
that can be accomplished in less than
30 minutes:
a. Chock the aircraft so it cannot be
moved.
b. Remove one spark plug from each
cylinder. This will make the propeller easier
and safer to turn.
c. Rotate one of the blades so it is
pointing down.
d. Place a solid object (e.g. a heavy
wooden block that is at least a couple of inches
higher off the ground than the distance be-
tween the propeller tip and the ground) next to
the propeller tip so that it just touches (see fig-
ure 8-30), or attach a pointer/indicator to the
cowling itself.
e. Rotate the propeller slowly to see if
the next blade “tracks” through the same point
(touches the block/pointer). Each blade track
should be within 1/16-inch (plus or minus)
from the opposite blade’s track.
f. If the propeller is out of track, it may
be due to one or more propeller blades being
bent, a bent propeller flange, or propeller
mounting bolts that are either over or under-
torqued. An out-of-track propeller will cause
vibration and stress to the airframe and engine,
and may cause premature propeller failure.
8-109. VIBRATION. Although vibration
can be caused by the propeller, there are nu-
merous other possible sources of vibration
which can make troubleshooting difficult.
a. If a propeller vibrates, whether due to
balance, angle, or track problems, it typically
vibrates, throughout the entire RPM range, al-
though the intensity of the vibration may vary
with the RPM. If a vibration occurs only at
one particular RPM or within a limited RPM
range (e.g. 2200-2350 RPM), the vibration is
not normally a propeller problem but a prob-
lem with a poor engine/propeller match.
b. If a propeller vibration is suspected
but cannot be positively determined, if possi-
ble, the ideal troubleshooting method is to
temporarily replace the propeller with one
which is known to be airworthy and test fly the
aircraft.
c. There are numerous allowable toler-
ances in blade angles, balance, track, and
blade width and thickness dimensions. These
tolerances have been established through many
years of experience. The degree to which
these factors affect vibration is sometimes dis-
puted and can involve significant repair bills,
which may or may not cure a vibration prob-
lem. Reliance upon experienced, reputable
propeller repair stations is the owner’s best
method of dealing with these problems.
d. Blade shake is not the source of vibra-
tion problems. Once the engine is running,
centrifugal force holds the blades firmly (ap-
proximately 30-40,000 lbs.) against blade
bearings.
e. Cabin vibration can sometimes be im-
proved by reindexing the propeller to the
crankshaft. The propeller can be removed,
rotated 180�, and re-installed.
Par 8-107
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