Aviation medical examinations cannot always predict is the precise moment when an apparently stable cardiovascular system becomes unstable. (File Photo) The death of an Air India first officer in Bali this week has unsettled far more than the aviation community. Here was a 40-year-old pilot, who was medically cleared pre-flight, operated within prescribed duty limits, completed an eight-hour flight, with no publicly known history of disease. He had checked into his hotel during a routine layover, complained of discomfort, had a heart attack and could not be revived despite being rushed to hospital. So how does someone pronounced fit enough to command an aircraft die of a cardiac event hours later? “The uncomfortable reality is that a heart attack comes like an earthquake, without prior notice, even in people who have every outward marker of health. An electrocardiogram (ECG) may appear normal in a resting state even when the arteries are blocked 70 per cent.…