Figure 3-4 Ammeter Placement For Current Measurement - Garmin GI 275 Installation Manual

Notes:
[1] If the landing gear warning or stall warning audio requires the audio panel, then the audio
panel must be included; otherwise, the audio panel is not essential for continued safe
flight/landing and may be omitted.
CAUTION
The pitot heat must be switched on long enough to take the current measurement and then
switched off. Since the pitot probe may get hot, ensure the probe cover is removed. Care
must be taken to avoid burns or damage to the unit.
4. The ammeter must be connected in line between the external power source and the master relay
circuit, as shown in Figure 3-4. This will eliminate errors due to the charging current drawn by the
battery.

Figure 3-4 Ammeter Placement for Current Measurement

5. With all circuit breakers closed, external power must be applied to the aircraft and voltage set to
the nominal alternator voltage (usually 13.8 VDC or 27.5 VDC).
6. The battery master switch must be turned on. Do not measure intermittent electrical loads. It is
assumed if any additional current is required beyond the alternator capability, this short-duration
demand will be supplied by the battery.
7. The following lighting settings must applied during the entire electrical load measurement:
a. All instrument panel and flood lights set to maximum brightness.
b. The GI 275 backlight set to 50% brightness.
c. All other backlit displays, including GPS navigator, set to 50% brightness.
8. Switch on all continuous electrical loads that are used for the taxiing phase of flight and record the
current that is measured by the ammeter (tabulated ELA form in column 1, Figure 3-5). The
autopilot circuit breaker must be closed, but the autopilot must not be engaged during the
measurement.
9. Switch on all continuous electrical loads that are used for the normal takeoff/landing phase of
flight and record the current that is measured by the ammeter (tabulated ELA form in column 2,
Figure 3-5). Measurements must be taken with the landing lights ON and OFF. The autopilot
circuit breaker must be closed and the autopilot must be engaged.
10. Switch on all continuous electrical loads that are used for the normal cruise phase of flight and
record the current that is measured by the ammeter (tabulated ELA form column 3, Figure 3-5).
The autopilot circuit breaker must be closed and the autopilot must be engaged.
11. Switch on all continuous electrical loads that are used for the emergency cruise phase of flight and
record the current that is measured by the ammeter (tabulated ELA form column 4, Figure 3-5).
Measurements must be taken with the landing lights ON and OFF.
12. Switch on all continuous electrical loads that are used for the emergency landing phase of flight
and record the current that is measured by the ammeter (tabulated ELA form column 5,
Figure 3-5). Measurements must be taken with the landing lights ON and OFF.
190-02246-14
Rev. 11
GI 275 STC EIS & MFD Installation Manual
Page 3-22