Originally Posted by
TwoFiftyBelowTen
I doubt that an alarm would have occurred at Mangalore pre-collision. Circuit areas of aerodromes such as Mangalore (anywhere with reasonable traffic numbers) have defined areas, lateral and vertical, within which alarms are inhibited or they would be going off all the time
if class E was 1500 at Mangalore the 2 IFR would never have collided as the would have been separated by ATC in CTA .