Why is it important for an aircraft technician to know standard light signals?

Understanding standard light signals is crucial for aircraft technicians primarily because they provide a method of communication when radio equipment fails. In situations where radio communication is compromised—due to equipment malfunction, interference, or emergency scenarios—light signals serve as a reliable alternative to convey instructions or information between the ground and the aircraft.

For instance, during landings and taxiing phases, if a pilot is unable to receive instructions via radio, ground personnel can utilize light signals to direct the aircraft safely. This ensures that crucial communication can still occur within the operational context of aviation, maintaining safety and operational integrity even in the absence of standard communication methods.

On the other hand, the other options do not accurately reflect the practical use of light signals in aviation. While it's true that light signals can assist in maintaining safety during critical phases, they do not serve as a replacement for cockpit instruments nor are they only relevant during takeoff, and dismissing their importance undermines the established protocols necessary for safe aircraft operations.