Disconnect Tone And Sonalert Test - Garmin GFC 500 Maintenance Manual

be maintained and is higher divide the measured voltage by current to get the
resistance value. Alternatively, calculate the percentage increase in current and then
reduce the measured voltage reading by the same percentage. Example: If the
measured current is 1.2 amps, (20% high from the desired 1 amp current) and the
measured voltage is 3.0 mV, then the value recorded will be 3 mV reduced by 20%
which is 2.4 mV which is the same as 2.4 mΩ.
4.5.3 Electrical Bonding Procedure
Using one of the two measurement methods in Section 4.5.2 record the bonding measurement
for the following equipment. Some equipment in the list is optional and may not be installed.
Ensure that the measurements do not exceed the values shown in Table 2-2. If the values
exceed those listed, perform the reconditioning procedure in Section 2.4.
•
GMC 507 case: __________ mΩ
•
GSA 28 (Roll) chassis: __________ mΩ
•
GSA 28 (Pitch) chassis: __________ mΩ
•
GSA 28 (Pitch Trim) chassis: __________ mΩ

4.6 Disconnect Tone and Sonalert Test

Perform the Disconnect Tone and Sonalert Functional Test at the intervals specified in Table
4-1.
1. Apply external electrical power to the aircraft and avionics systems.
2. Ensure that the GFC 500 Autopilot passes PFT.
3. Engage the autopilot by pressing the AP button on the GMC 507.
4. Disengage the autopilot by pressing the AP DISC/TRIM INT switch on the pilot's flight
controls.
5. Verify that the normal autopilot disconnect tone plays.
a. If an audio panel is connected, verify that the autopilot disconnect tone plays through
the speaker and headphones. NOTE: The normal autopilot disconnect tone is three
high-low tones approximately three seconds in duration.
b. If a sonalert is connected, verify that the autopilot disconnect tone plays through the
sonalert. NOTE: The normal autopilot disconnect sonalert tone is a continuous 2000
Hz tone that plays for approximately 3 seconds.
GFC 500 Autopilot with ESP Part 23 AML STC Maintenance Manual
190-02291-01
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Revision 1