I am confused with the tense in this sentence because whole artical use present but just in this sentence use past tense. besides, I do not know which word is the subject of ‘required’? and how should I understand the ‘significantly’, dose it mean dramatically and data changes with implementation closely ?
the role and importance of aeronautical information/data changed significantly with the implementation of area navigation, required navigation performance and airborne computer-based navigation system.
The past tense indicates that the role and importance of the data had already changed when the article was written. Significantly means “a lot”. The sentence suggested big changes but did not how much or in what way. It is trying to say that, before, pilots navigated from waypoint to waypoint with the aid of radio navigation (like VOR and DME) so if the waypoint is printed wrong on a paper chart, it wasn’t as important as it is now, with (the implementation of ) area navigation where the computer performs the navigation. The data the computer has have to be accurate. Hope this helps…
“Required Navigation Performance” is a technical term, commonly referred to as RNP. It specifies how accurate your equipment has to be to be operating in a particular area navigation (RNAV) operation.
