The driver, operator or attendant of any refueling service vehicle shall be in attendance when the vehicle is fueling or refueling an aircraft and shall have, under his control, the delivery of fuel through the use of approved fueling control devices designed to shut-off automatically at the hydrant outlet. Under these controlled conditions, a single driver or operator may perform the complete servicing of any aircraft provided the distance between the automatic shut-off device and the mechanism it controls shall not exceed 100 feet.