In a V-n diagram, what does the limit load factor line indicate?

• A. The maximum altitude for safe flight.
• B. The maximum airspeed for maneuvering.
• C. The load factors the aircraft can sustain at a given airspeed before structural failure.
• D. The engine failure threshold.

Answer: (C)

In a V-n diagram, the limit load factor line defines the maximum structural load factors the airframe is designed to withstand at each airspeed. It marks the boundary of safe operation: at any given speed, going beyond this line means the forces on the aircraft exceed its design limits and could cause structural failure. This line is about structural capability, not altitude, not maximum airspeed for maneuvering in general, and not engine thresholds. So it best describes the load factors the aircraft can sustain at a given airspeed before structural failure.