Under what condition are the probes automatically heated?

• A. When one engine is started and its generator comes on line.
• B. Only after both engines are started
• C. When the aircraft is at high altitude
• D. When the aircraft is on the ground with parking brake engaged

Answer: (A)

Probe heating is powered by the aircraft’s electrical system. When any engine is started and its generator comes online, that electrical power feeds the probe heating circuit, so the probes automatically heat. This keeps the sensors free of ice and ensures accurate readings as you start and fly. It doesn’t require both engines, it isn’t triggered by altitude, and the parking brake status on the ground isn’t what starts the heating.