What is the ICAO minimum non-radar separation time for a LIGHT aircraft behind a MEDIUM or HEAVY aeroplane on approach to the same runway?

The correct answer is three minutes because this is the established ICAO standard for non-radar separation between aircraft categories during approach. The separation is designed to ensure safety due to the wake turbulence generated by larger aircraft. A LIGHT aircraft following a MEDIUM or HEAVY aircraft needs a minimum of three minutes to allow enough time for any wake turbulence to dissipate and for the LIGHT aircraft to safely enter the landing phase without being affected by the wake effects of the preceding aircraft. Understanding this is crucial for pilots and air traffic controllers in maintaining safe distances in various operational scenarios, ensuring that all flights can operate without undue risk of wake turbulence encounters.