ATTITUDE AND DIRECTION (Cont.)
DIRECTIONAL GYRO
Directional gyro is a flight instrument incorporating an air driven gyro stabilized in vertical plane. Gyro is
rotated at high speed by lowering pressure in air tight case and simultaneously allowing atmospheric air
pressure to enter instrument against gyro buckets. Due to gyroscopic inertia, spin axis continues to point in
same direction even though aircraft yaws to right or left. This relative motion between gyro and instrument
case is shown on instrument dial which is similar to a compass card. Dial, when set to agree with airplane
magnetic compass, provides a positive indication free from swing and turning error. However, directional
gyro has no sense of direction and must be set to magnetic compass. Since magnetic compass is subject to
errors due to magnetic fields, electric instruments, etc, directional gyro is only accurate for heading it has
been set for. If gyro is set on 270°, for instance, and aircraft is turned to some other heading, there can be a
large error between gyro and magnetic compass due to error in compass compensation. This will appear as
gyro precession. Gyro should only be checked to heading on which it was first set. Due to internal friction,
spin axis error, air turbulence and airflow, gyro should be set at least every 15 minutes for accurate
operation, whether it has drifted or not.
CHART 5
TROUBLESHOOTING DIRECTIONAL GYRO INDICATOR
MAGNETIC COMPASS
Magnetic compass is a self-contained instrument. This instrument has an individual light which is connected
to instrument lighting circuit. Compass correction card is located in card holder mounted on instrument.
Compass should be swung whenever instruments or radios are changed and at least once a year.
PIPER AIRCRAFT
PA-32R-301/301T
MAINTENANCE MANUAL
34-20-00
Page 34-10
Reissued: July 1, 1993
3E23
Trouble
Cause
Remedy
Excess drift in either
Setting error.
Review paragraph titled
direction.
“General” for gyro operation.
Defective instrument.
Replace instrument.
High or low vacuum. If vacuum
is not correct, check for the
following:
1. Relief valve improperly
1. Adjust.
adjusted.
2. Incorrect gauge reading.
2. Replace gauge.
3. Pump failure.
3. Repair or replace.
4. Vacuum line kinked or
4. Check and repair. Check
leaking.
for collapsed inner wall of
hose.
Dial spins during turn.
Limits (55° bank) of gimbal
Recage gyro in level flight.
exceeded.
Dial spins continuously.
Defective mechanism
Replace.
Summary of Contents for PA-32R-301T SARATOGA S
Page 26: ...CHAPTER 4 AIRWORTHINESS LIMITATIONS 1C1 ...
Page 29: ...CHAPTER 5 TIME LIMITS MAINTENANCE CHECKS 1C4 ...
Page 53: ...CHAPTER 6 DIMENSIONS AND AREAS 1D6 ...
Page 64: ...CHAPTER 7 LIFTING AND SHORING 1D21 ...
Page 68: ...CHAPTER 8 LEVELING AND WEIGHING 1E1 ...
Page 72: ...CHAPTER 9 TOWING AND TAXIING 1E5 ...
Page 76: ...CHAPTER 10 PARKING AND MOORING 1E9 ...
Page 80: ...CHAPTER 11 REQUIRED PLACARDS 1E13 ...
Page 92: ...CHAPTER 12 SERVICING 1F1 ...
Page 126: ...CHAPTER 20 STANDARD PRACTICES AIRFRAME 1G17 ...
Page 127: ...THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 139: ...CHAPTER 21 ENVIRONMENTAL SYSTEMS 1H5 ...
Page 188: ...CHAPTER 22 AUTOFLIGHT 1J7 ...
Page 193: ...CHAPTER 23 COMMUNICATIONS 1J12 ...
Page 203: ...CHAPTER 24 ELECTRICAL POWER 1J22 ...
Page 263: ...CHAPTER 25 EQUIPMENT FURNISHINGS 2A13 ...
Page 269: ...CHAPTER 27 FLIGHT CONTROLS 2A20 ...
Page 332: ...CHAPTER 28 FUEL 2D11 ...
Page 363: ...CHAPTER 29 HYDRAULIC POWER 2E18 ...
Page 404: ...CHAPTER 30 ICE AND RAIN PROTECTION 2G16 ...
Page 470: ...CHAPTER 32 LANDING GEAR 3A13 ...
Page 550: ...CHAPTER 33 LIGHTS 3D24 ...
Page 562: ...CHAPTER 34 NAVIGATION AND PITOT STATIC 3E12 ...
Page 582: ...CHAPTER 35 OXYGEN 3F8 ...
Page 604: ...CHAPTER 37 VACUUM 3G6 ...
Page 616: ...CHAPTER 39 3G18 ELECTRIC ELECTRONIC PANELS MULTIPURPOSE PARTS ...
Page 620: ...CHAPTER 51 STRUCTURES 3G22 ...
Page 636: ...CHAPTER 52 DOORS 3H14 ...
Page 650: ...CHAPTER 55 STABILIZERS 3I4 ...
Page 662: ...CHAPTER 56 WINDOWS 3I16 ...
Page 670: ...CHAPTER 57 WINGS 3I24 ...
Page 688: ...CHAPTER 61 PROPELLER 3J18 ...
Page 704: ...CHAPTER 70 STANDARD PRACTICES ENGINES 3K10 ...
Page 708: ...CHAPTER 71 POWER PLANT 3K14 ...
Page 737: ...CHAPTER 73 ENGINE FUEL SYSTEM 4A13 ...
Page 749: ...CHAPTER 74 IGNITION 4B1 ...
Page 783: ...CHAPTER 77 ENGINE INDICATING 4C11 ...
Page 793: ...CHAPTER 78 EXHAUST 4C21 ...
Page 801: ...CHAPTER 79 OIL 4D5 ...
Page 805: ...CHAPTER 80 STARTING 4D9 ...
Page 819: ...CHAPTER 81 TURBINES 4D23 ...
Page 833: ...CHAPTER 91 CHARTS WIRING DIAGRAMS 4E13 ...