Taxi lights must be switched off whenever the airplane is stationary in excess of how many minutes?

• A. 5 minutes
• B. 10 minutes
• C. 15 minutes
• D. 20 minutes

Answer: (B)

When an aircraft is on the ground and not actively moving, the electrical load from nonessential lights should be kept to a minimum to conserve power and protect the electrical system. Taxi lights are mainly for illumination during taxiing, not for being left on while parked. So after the aircraft has been stationary for a while, turning off the taxi lights helps reduce battery and generator/APU load and avoids unnecessary wear. Ten minutes is the practical threshold that balances safety and efficiency: it allows lighting for any brief movements or ground procedures, but prevents wasting power during longer holds. Five minutes would switch off too soon for typical ramp holds, while fifteen or twenty minutes would unnecessarily drain power without adding safety benefits.