3 turns, word for word from the oral. Read the pilot lines out loud.
MAYDAY MAYDAY MAYDAY Mumbai Control IFLY 160 Heavy, primary altimeter system failed, returning to Mumbai, position DME 40, 15 DME right of radial 250, unsure of FL, estimating BBB in 20 min, request descent
IFLY 160 roger your MAYDAY, descent at your discretion, report over BBB or aerodrome in sight, report level when you get on radio altimeter
Leaving our present level, descending at our discretion, will report BBB or aerodrome in sight, will report level when on radio altimeter