What does the Radio Magnetic Indicator (RMI) help determine?

The Radio Magnetic Indicator (RMI) is an essential navigational instrument used in aviation, particularly for determining an aircraft's position relative to navigational aids (NAVAIDS). It combines both magnetic compass and navigation signal information, facilitating the identification of the aircraft's orientation towards various NAVAIDS such as VOR stations. The RMI displays the magnetic heading of the aircraft and the bearings to the selected NAVAIDS, which allows pilots to accurately navigate and ensure they are on course.

This capability is crucial during various phases of flight, especially in low visibility conditions or when flying in proximity to busy airspace. Understanding the aircraft's position in relation to these aids is vital for safe navigation, making the RMI a key tool for pilots. The other options do not pertain to the RMI's function and instead relate to areas like weight management, performance metrics of the engines, or altitude settings, which are not functions of the RMI.