THE NEW PIPER AIRCRAFT, INC.
PA-32-301FT / 301XTC
MAINTENANCE MANUAL
PAGE 7
Feb 19/04
3H21
34-10-00
4. Airspeed Indicator
A. Description
The airspeed indicator provides a means of indicating speed of airplane passing through air.
Airspeed indication is differential pressure reading between ram air to pressure and static air
pressure. This instrument has diaphragm vented to pitot air source and case is vented to static air
system. As airplane increases speed, pitot air pressure increases, causing diaphragm to expand. A
mechanical linkage picks up this motion and moves instrument pointer to indicated speed.
Instrument dial is calibrated in knots, and also has necessary operating range markings for safe
operation of airplane.
NOTE: When any connections in the static system are opened for checking, system must be
rechecked per FAR 23.1325.
B. Troubleshooting
See Chart 3.
CHART 3
TROUBLESHOOTING AIRSPEED INDICATOR AND LINES
Trouble Cause Remedy
Pointers of stick instruments Leak in instrument case or Check for leak and seal.
do not indicate properly. in pitot lines.
Pointer of instrument Defective mechanism. Replace instrument.
oscillates.
Instrument reads high. Pointer not on zero. Replace instrument.
Leaking static system. Find leak and correct.
Instrument reads low. Pointer not on zero. Replace instrument.
Leaking static system. Find leak and correct.
Pitot head not aligned correctly. Realign pitot head.
Airpeed changes as aircraft Water in pitot line. Remove lines from static
is banked. instruments and blow out
lines from cockpit to pitot
head.
To Next Page
Loading...
Need help?
General