Henry Bailey formed his attachment with the flying business as a boy wireless operator on board zero type airships on anti-submarine patrol in the Channel during the First World War. After a post-war spell as an engineer he took a short-service commission in the RAF, in which he became a flying instructor.
He left the service in 1932,joining North Sea Aerial and General Transport Ltd, with whom he served as a flying instructor at the Brough Flying School. On many occasions he did test-flying for the Blackburn Company and in 1936 he was appointed assistant test pilot To Flt Lt A.M Blake before becoming Chief Test Pilot on Blake’s death the following year. He performed the maiden flight of the Blackburn Botha and the B20 flying boat, which took to the air in March 1940. On the first flight it was found that there was a problem with the aileron trim and it took four or five more test flights to sort this out (there were no trim tabs on the ailerons and alterations could only be done on the ground). In the process it had a birdstrike and repairs had to be carried out. On the 7th April 1940 the B20 took to the air for its first attempt at a high speed run. The flight that day was over the Forth of Clyde and Sound of Bute on Scotland's west coast. A high speed run took place at which a speed of 345 mph was reached, but shortly afterwards severe vibration set in. Reducing speed did not help and Flt Lt Bailey ordered the crew to take to their parachutes. Up in the cockpit Fred Weeks was able to get out of one of the escape hatches in the roof, but Ivan Waller deployed his 'chute too early and it got caught in the radio mast with him only half way out of the escape hatch. Then the vibration stopped and Ivan was able to climb along the top of the fuselage, untangle his parachute and drop free. Flt Lt Bailey stayed with the aircraft until the last possible moment to give the other two crew members a chance to escape, his parachute did not open fully and he was drowned.