Final answer:
No drop in RPM when switching from BOTH to RIGHT position suggests the right magneto of the aircraft's ignition system is functioning correctly and the engine is efficiently using that ignition source.
Step-by-step explanation:
Having no drop in RPM when the switch is moved from BOTH to RIGHT position could indicate that the aircraft's ignition system is functioning correctly on the right side. In an aircraft, the ignition system is typically made up of two magnetos, one for each side of the engine (left and right), to provide redundancy. The BOTH position on the ignition switch allows the engine to operate with both magnetos, while selecting LEFT or RIGHT isolates the respective magneto. A lack of RPM drop when selecting the RIGHT magneto alone suggests that the right magneto is producing a good spark and the engine is running efficiently on that ignition source. If there were an issue with the right magneto, you would expect to see a noticeable drop in RPM, as the engine would only be running on the left magneto with potentially degraded performance.