[spankytoo]

315 - E, The use of any data collection device is not permitted.

From GoPro:

Yes, GoPro cameras can measure g-force and other data using the Quik for Desktop app and the camera's telemetry feature:
Telemetry feature
The Quik for Desktop app can use GPS data to capture and overlay g-force, speed, altitude, and more as graphics on videos. The overlays are customizable, allowing users to resize and move the gauges, and turn on or off each data graphic.
Adjust gauges
The GoPro Quick app allows users to add gauges, including g-force, speed tracker, GPS path, and speedometer.
Height Altitude and G Force Speed XYZ Direction Sensor This pack can be plugged into the back of a GoPro camera to record altitude and acceleration forces while recording video. The data is then overlaid as subtitles on the recording.
Depending on the model, GoPro cameras may also have other features, such as a gyroscope, accelerometer, GPS, and more.