Less than 2 minutes in a Tucano.
Lifted from Linton to find the cockpit filled with an overpowering smell of Tippex. Toggled down and 100% oxy made the smell far, far worse and started to feel quite light headed. Emergency oxy pulled and landing made. Subsequent investigation found that the main oxy bottle had been washed with 1-1-1 Trichloroeathane and it hadn't been properly rinsed out afterwards. The Doc then grounded us for 48 hours which gave a nice long weekend
