Which practical test should be made on the electric gyro instruments prior to starting an engine?

Which practical test should be made on the electric gyro instruments prior to starting an engine?

• A. Check that the attitude of the miniature aircraft is wings level before turning on electrical power.
• B. Check that the electrical connections are secure on the back of the instruments.
• C. Turn on the electrical power and listen for any unusual or irregular mechanical noise.
• D. Verify vacuum pump is running.

Answer: (C)

Electric gyro instruments are driven by small electric motors, so the key preflight check is to apply electrical power and listen for any unusual or irregular mechanical noise. Powering them up first lets the gyros spin and reveals bearing or drive problems that could cause incorrect attitude indication during flight. If you hear abnormal grinding or binding, that signals a potential failure that should be addressed before engine start or flight. The other checks aren’t as effective here: a wings-level indication with power off doesn’t verify the instrument’s mechanical condition, and a vacuum pump check isn’t relevant because electric gyros don’t rely on vacuum.

Electric gyro instruments are driven by small electric motors, so the key preflight check is to apply electrical power and listen for any unusual or irregular mechanical noise. Powering them up first lets the gyros spin and reveals bearing or drive problems that could cause incorrect attitude indication during flight. If you hear abnormal grinding or binding, that signals a potential failure that should be addressed before engine start or flight. The other checks aren’t as effective here: a wings-level indication with power off doesn’t verify the instrument’s mechanical condition, and a vacuum pump check isn’t relevant because electric gyros don’t rely on vacuum.