Mooney M20TN, Service And Maintenance Manual

Page: 343 / 1169

MOONEY AVIATION COMPANY, INC.
M20TN SERVICE & MAINTENANCE MANUAL
Date
2006
Rev Date
Page 9
E. Hold compass in place to see if headings now
match aircraft heading. If too much heading error (more
than
±
15
°
) still exists, remove compass from aircraft.
F. Turn growler ON and move it along center side
and overhead cross structure from one side of cockpit
to the other. Turn OFF growler.
G. Again, hold compass in place and compare
headings. If heading error has not reduced sufficiently
(to less than
±
15
°
), then:
1) Repeat steps D, E, F and G.
H. When heading error is reduced to less than
±
15
°
, install compass and proceed to Step 4 – Compass
Swinging.
4. Compass Swinging:
A. Run engine at 1200 to 1500 RPM and proceed
to swing compass with radio “ON” after reinstalling and
centering compensator magnets (if removed).
B. Position aircraft on compass rose and adjust
N--S compass compensating screw (left screw) for a 0
°
indication at north heading (Use non--ferrous tools).
C. Turn aircraft to east heading and adjust com-
pass E--W compensator screw (right screw) for a 90
°
indication.
D. With aircraft on south heading adjust N--S com-
pensator to reduce indicated error by 50 percent (ex-
ample: If compass reads 184
°
, adjust compensators so
it reads 182
°
).
E. With aircraft on west heading adjust E--W com-
pensator to reduce indicated error by 50 percent.
F. Return aircraft to north heading, reset directional
gyro and, using DG, check and record compass error at
every 30
°
heading through 360
°
.
G. Adjust compensator making sure compass
reads within
±
10
°
at any heading and proceed to step
5. If compass does not read within
±
10
°
at any heading,
proceed to de--magnetize cockpit as outlined in Step 3.
5. Fill out compass correction card giving “Radio ON”
corrections through 360
°
. Install card on or in close
proximity to compass in full view of pilot.
34--22--02 -- COMPASS TROUBLESHOOTING (TRADITIONAL COMPASS)
TROUBLE PROBABLE CAUSE REMEDY
Excessive card error. Compass not properly compen-
sated.
Compensate instrument.
External magnetic interference. Locate magnetic interference and
eliminate, if possible.
Excessive card oscillation. Improper instrument mounting. Align instrument.
Insufficient liquid. Replace instrument.
Sluggish card. Weak card magnets. Replace instrument.
Excessive pivot friction or broken
jewel.
Replace instrument.
Instrument too heavily compen-
sated.
Correct excess compensation.
Liquid leakage. Loose bezel screws. Tighten screws.
Broken cover glass. Replace instrument.
Defective sealing gaskets. Replace instrument.
Discolored luminous markings or
discolored damping liquid.
Age Replace instrument.
Defective light. Burnt out lamp or broken circuit. Check lamp or wiring continuity.
34--23--00 -- ATTITUDE INDICATOR
The attitude information displays over a virtual blue sky
and brown ground with a white horizon line. The aircraft
wing tips are represented by two yellow bars on the ho-
rizon line. The yellow inverted “V” represents the air-
craft. The Attitude indicator displays the following infor-
mation:
•
Pitch indication
•
Roll indication
•
Slip/Skid indication
Pitch Indication:
Major pitch marks and numeric labels at 10
°
, 20
°
, 30
°
,
40
°
, 50
°
, 60
°
, 70
°
and 80
°
are shown above and below
the horizon line. Minor pitch marks at 5
°
, 15
°
and 25
°
above the horizon line and 5
°
, 15
°
, 25
°
, 35
°
and 45
°
be-
low the horizon line are shown. The horizon line is part
34--22--02