AIR TRACTOR AT-502A, Секция обслуживания

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Maintenance Page 70 Air Tractor, Inc.
March 14, 2018 AT-502A/502B/504
SYSTEMS WITH LEAD RESISTANCE (Power NOT Required)
1. Aircraft power should be OFF during this procedure.
2. Disconnect the leads from the back of the instrument in the cockpit. Note which lead connects to
which terminal.
3. On t
he TT1200, set the “FUNCTION” switch to “RES MEAS.”
4.
Set the “RANGE” switch to “200.”
5.
Attach the harness to the “TEST” connector on the TT1200.
6.
Set the “ON/OFF” switch of the TT1200 to “ON.”
7. Short the tester by connecting the red and black clips of the harness together. While the tester
is shorted, press and hold the “PTS” button while adjusting the “SYS RES” control knob until the
“08.00
Ω ” is displayed on the tester.
8.
Disconnect the harness clips and set the “FUNCTION” switch to “IND TEST.”
9.
Set the “1°C/.1°C switch to “1°C.”
10.
Set the “C/MV” switch to “C.”
11. Connect the black clip of the harness to the instrument terminal that had the Red (-) lead
attached, and connect the red clip to the instrument terminal that had the Yellow (+) lead
attached.
12. For the calibration check, the operator will need to take readings from the gauge inside of the
cockpit as well as at the test set near the engine.
a.
Rotate the “TEMP ADJ” knob on the test set so that a temperature of 200°C is indicated
on the ITT indicator in the cockpit. Record the temperature off of the TT1200 test set.
b. Repeat this for each temperature shown on the Sample Test Card.
c. Adjust the temperature knob on the test set so that the ITT indicator lines up exactly with
the red line. Record the temperature of the line, as well as the temperature indicated on
the test set.
d. Lastly, adjust the temperature knob on the test set so that the ITT indicator points at the
red triangle. Record the temperature of the red triangle, as well as the temperature
indicated on the test set.
13. Once all temperatures are recorded from the TT1200 and the instrument, turn the TT1200 OFF,
disconnect the test equipment, and return the aircraft to the configuration prior to testing.
14. Compare the readings from the TT1200 and the instrument. See the appropriate table below for
tolerances. If the instrument is not within acceptable calibration send the instrument to a shop
for overhaul and calibration.