When the landing gear is down, the green light will not come on if an open condition occurs in which wire?

• A. No. 17
• B. No. 7
• C. No. 6
• D. No. 4

Answer: (C)

The main idea is that an indicator light is part of a complete electrical circuit, and the light will only come on if the circuit path delivering current to it is intact. For the landing gear green light, the gear-down signal must travel through a specific wire as part of that indicator circuit. If that wire develops an open condition, the path is broken and current can’t reach the green light, so it won’t illuminate even though the gear is down. The other wires in the choices aren’t in the same series path to the green indicator, so an open in those wires wouldn’t prevent the light from energizing. In short, only the wire that carries the gear-down signal to the green lamp is in the crucial path; an open there stops the light from coming on.