Mooney M20TN, Service And Maintenance Manual

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MOONEY AVIATION COMPANY, INC.
M20TN SERVICE & MAINTENANCE MANUAL
Page
Date
12
2006
Rev Date
6. The best plan is to stop the noise at its source.
Once the noise is
S
loose
S
, it can be difficult to filter it out
of all affected systems. Try to locate the offending item
and correct the problem at that point. Switching off the
alternator, the mags (first one then the other), or any
other electrical equipment that generates noise should
help to find the offender.
24--31--04 -- AUXILIARY POWER SYSTEM
An auxiliary power plug and related circuitry is installed
to provide an outside source of electrical power to the
aircraft (No. 1 Battery Switch must be selected), to
charge the No. 1 battery, or to start the engine. Battery
#2 will have to be charged separately. The Auxiliary
Power Plug guide pin must have A+ voltage connected
to it in order to activate the Auxiliary Power Relay. The
No. 1 battery can be charged using the approved Auxil-
iary Power Cable connected to a charge cart capable of
regulating the charging current. To prevent battery
damage, the charging current should be low (3 -- 4
amps) to begin and then increased as the battery volt-
age capacity is increased. The MASTER SWITCH is
not required to be ON for the auxiliary power source to
charge the batteries. During flight, the non--selected
battery is receiving a trickle charge from the aircraft al-
ternator to keep it at peak voltage.
A. When auxiliary power or a booster battery is
used, be sure cables are connected correctly -- positive
to positive and negative to negative. DO NOT by--pass
batteries when using an auxiliary power source.
B. See paragraph 24--34--00, A for additional infor-
mation.
-- CAUTION --
Only when performing functional checks on
ground, First connect the approved Auxiliary
Power Cable to the booster battery and then in-
sert the plug into the auxiliary power receptacle.
24--32--00 -- BATTERY MAINTENANCE
-- CAUTION --
Battery gases are explosive.
1. Battery Removal.
A. Turn Master Switch -- OFF.
B. Remove tailcone access cover and battery hold
downs.
C. Disconnect battery cables, negative lead first
D. Remove battery hold--down and remove battery
from aircraft.
E. Install battery in reverse sequence of removal.
Safety hold--down hardware. Use a voltmeter to verify
battery polarity before installation.
2. Battery Cleaning and Corrosion Removal
A. Mix one pound of baking soda (bicarbonate of
soda) in one gallon of water.
B. Wash battery mounting area and flush battery
with mixture. Do not allow soda water to enter battery
cells; permanent damage will result if soda mixes with
electrolyte.
C. Rinse thoroughly with clear water; dry the area.
D. Clean battery terminals with emery cloth, rein-
stall and tighten cables. Coat terminals and connectors
with petroleum jelly to retard corrosion.
E. While batteries are removed from aircraft; verify
condition of the three 10A Slo--Blo fuses in the trickle
charge diode circuit located in the tailcone.
24--33--00 -- WARNING CIRCUITS
1. Landing gear position lights and warning horn.
RED and GREEN landing gear position lights are in the
annunciator panel. The gear--down limit switch controls
the GREEN gear--down light. Both limit switches con-
trol the RED gear unsafe light.
The throttle control operates the landing gear warning
(CHECK GEAR annunciator and aural) when the
throttle is retarded to within 1/4 inch of the IDLE position
and the landing gear is still in the UP position. This must
be checked during a flight test by verifying that the
check gear warning occurs when the throttle is retarded
and the landing gear is still in the UP position.
2. Pre--stall Warning Circuit. The pre--stall warning
Sonalert tone is heard and approximately one second
later a “STALL” voice alert is annunciated over the
speaker.
A vane in the left wing leading edge actuates the pre--
stall warning horn switch. (This vane is made of heat
treated steel and any attempt to adjust switch operation
point by bending the vane will damage the switch). Re-
fer to Section 27--95--00 for adjustment procedures.
3. Low Fuel Warning Circuit. The low fuel indicators
will illuminate when a minimum of 6 gallons usable fuel
remains in either left or right hand tank.
Refer to Garmin G1000 Maintenance Manual for Fuel
Quantity Calibration instructions.
4. Alternate Air Light Warning Circuit -- Annunciator
Panel. The light illuminates on the annunciator panel
when the alternate air door has opened for any reason.
5. Hi/Low Voltage Warning Circuit -- Annunciator
Panel. Remove annunciator top cover. Connect a volt-
meter to aircraft Buss. Start engine and increase RPM
until flashing ”VOLTS” light extinguishes. (This should
be above 26.6 volts). Add load, such as Pitot Heat &
Nav. Lights. Slowly decrease RPM while monitoring
voltage until light begins to flash. This should occur be-
tween 26.6 & 26.4 volts.
24--31--04
AUGUST 2010