Final answer:
When backing an R-12 servicing vehicle towards an aircraft, a spotter must always be present to guide the driver and prevent accidents.
Step-by-step explanation:
When backing an R-12 servicing vehicle towards an aircraft, you must always have a spotter. This is a standard safety procedure to prevent any possible collisions or accidents that may occur due to the vehicle's blind spots while reversing.
It is crucial that the spotter maintains clear communication with the driver, providing guidance to ensure the vehicle moves safely and avoids any potential harm to personnel or damage to the aircraft.