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Aircraft general knowledge

8.12.3 Other instruments

8.12.3.1 Vacuum gauge

The vacuum gauge indicates whether there is vacuum for the gyro instruments.

The checklist will state what the vacuum gauge should indicate. Some

instruments have a green arc.

The picture here shows a combined vacuum- and

ammeter.

8.12.3.2 Ammeter

Ammeters can be inserted into circuits in several ways.

The ammeter can indicate how much current is being used in total. It can be

connected so that it can indicate whether the battery is being charged or

discharged.

8.12.3.3 Voltmeter

A voltmeter indicates the voltage in the aircraft's electrical

system, which is used to monitor the performance of the

battery and generator.

8.12.3.4 Flap indicator

The flap indicator shows how much flap is set.

8.12.3.5 Low Voltage Warning

The lamp lights up if the voltage falls below 13 V or 26 V, because

then the voltage is too low for charging the battery.

Press the bulb to test.

Flyveteori PPL(A)(UL)/LAPL Henning Andersen, Midtjysk Flyveskole© 2025 765