Which parameter does the accelerometer indicate in flight?

• A. Angle of attack
• B. G load
• C. Roll rate
• D. Vertical velocity

Answer: (B)

An accelerometer in flight measures all linear accelerations acting on the aircraft along its three axes, including gravity. The value it indicates is the load factor, or G load, which is the total acceleration divided by Earth's gravity. In straight-and-level flight, the reading is about 1 g. During maneuvers, the aircraft experiences additional forces, so the G load rises above 1 when pulling up and can fall toward or below 1 during descent or aggressive pitch, reflecting the stress on the airframe.

Angle of attack is determined by sensing the wing’s orientation relative to the oncoming air, not by linear acceleration. Roll rate is the rate of rotation around the aircraft’s longitudinal axis, measured by gyros. Vertical velocity is the rate of climb or descent, measured by altimeter systems. While accelerometers contribute to the overall inertial navigation data, the specific parameter described here is the G load.