What the paper testsBands, ranges, errors and failures
Radio aids questions cluster around four things for every system: what frequency band it uses, what range and coverage it gives, what errors it suffers, and how it fails.
Learn each aid against that four-part frame and most of the paper answers itself — including the questions phrased as a scenario rather than a definition.
Why it is its own subjectDGCA examines ATPL in three parts
General Navigation, Meteorology, and Radio Aids & Instruments are three separate DGCA subjects with three separate papers, so AIVR CPL holds them as three separate banks with independently tracked readiness.
Where marks go missingSlant range and false glidepaths
The predictable losses are the ones that punish an assumption: DME giving slant range rather than ground distance, ILS false glidepaths above the true one, VOR errors that depend on terrain and aircraft position, and GNSS accuracy claimed without RAIM.
Instruments contribute their own: the compass errors, and what an INS or IRS actually drifts by.
How to work through itOne aid at a time
Take a single system — VOR, say — and work it until band, range, errors and failure modes are all automatic. Then move to the next. Working through this subject aid by aid is far more efficient than sampling across it.
Then sit the 100-question paper on the clock.