The aircraft in question was not a PA28 and the approach speed in the POH is quoted as 55kias. Not 70 as the instructor was insisting upon. As for the C172, the speeds quoted in my own POH are INDICATED airspeeds and nothing else.
Part of my initial training (many moons ago) consisted of approaches and landings with ALL of the instruments covered. Those were the days.
Back to painting the shed.
Airplane pilot prank goes wrong, yet right