Figure 3-10 Ammeter Placement For Current Measurement - Garmin GI 275 Installation Manual

Figure 3-10 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 3-11). 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 3-11). 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 3-11).
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 3-11).
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 3-11). Measurements must be taken with the landing lights ON and OFF.
The aircraft electrical system is capable of supporting the GI 275 system if the maximum electrical system
demand, as documented on the tabulated ELA form, does not exceed 80% of the alternator capacity. It is
permissible for the electrical load to exceed 80% of the alternator capacity when the pitot heat and landing
light are both switched on during the takeoff/landing phase of flight. In this case, the electrical load must
not exceed 95% of the alternator capacity. If the pitot heat is on and the landing light is off, the electrical
load may not exceed 80% of the alternator capacity.
NOTE
The Electrical Load Analysis for this installation is only valid for modifications performed
under this STC. Subsequent changes to the aircraft electrical system will require a new
load analysis.
190-02246-10
Rev. 11
GI 275 Part 23 AML STC Installation Manual
Page 3-32