Piper Aircraft Corporation Malibu Mirage PA-46-350P, Airplane Maintenance Manual

Page: 1456 / 1956

PAGE 2
Feb 28/07
7H10
77-10-00
PIPER AIRCRAFT, INC.
PA-46-350P, MALIBU MIRAGE
MAINTENANCE MANUAL
2. Tachometer Indicator
NOTE: S/N’s 4636021 and up incorporate Integrated Engine Instrumentation Systems. See 77-40-00.
A. Description
The tachometer is electrically connected to the engine magnetos. The tachometer provides an
indication of crankshaft speed in revolutions per minute. The instrument has a recording mechanism
for recording the time that the engine is in actual operation. A calibration check on the tachometer is
performed every 100 hours. The correct tolerance at 2,500 rpm is (-) 25 rpm (+) 0 rpm.
B. Troubleshooting
See Chart 2.
CHART 2
TROUBLESHOOTING TACHOMETER INDICATOR
Trouble Cause Remedy
No reading on indicator, Inoperative instrument. Replace instrument.
either permanent or
intermittent.
Loose cable connections. Tighten cable.
Pointer oscillates Inoperative instrument. Replace instrument.
excessively. Excessive friction in Replace instrument.
instrument.
Indicator changes in Excessive cleanup in Replace instrument.
climb. speed cup.
Pointer goes all the way Excessive lubricant in Replace instrument.
to stop, more noticeable instruments.
in cold weather.
Pointer jumps at idle. Speed cup hitting rotating Replace instrument.
magnet.
Tachometer cable breaks. Cable bent too sharply. Reroute cable.