The electrically variable transmission family provides low-content, low-cost electrically variable transmission mechanisms including first, second and third differential gear sets, a battery, two electric machines serving interchangeably as motors or generators, up to six selectable torque-transfer devices, and possibly a dog clutch. The rotation-measuring unit is arranged to output a first signal dependent on the steering angle between a nose landing gear of the aircraft and the longitudinal axis of the aircraft fuselage. A processor configured to assign a risk identifier to the driving event, to generate an event score based at least in part on the risk identifier, and to generate a driver score based at least in part on the event score and one or more driver challenge factors.