0n 19 August 1940, Johnson flew a Spitfire for the first time. Over the next weeks he practised handling, formation flying, attacks, battle climbs, aerobatics and dogfighting. During his training flights, he stalled and crashed a Spitfire. Johnson had his harness straps on too loose, and wrenched his shoulders – revealing that his earlier rugby injury had not healed properly. The Spitfire did a ground loop, ripping off one of the undercarriage legs and forcing the other up through the port main plane. The commanding officer (CO) excused Johnson, for the short airfield was difficult to land on for an inexperienced pilot. Johnson got the impression, however, that he would be watched closely, and felt that if he made another mistake, he would be "certainly washed out". Johnson tried to pack the injured shoulder with wool, held in place by adhesive tape. He also tightened the straps to reduce vibrations while flying. The measures proved useless and Johnson found he had lost feeling in his right hand. When he dived the pressure aggravated his shoulder. He often tried to fly using his left hand only, but Spitfires had to be handled with both hands during anything other than simple manoeuvres. Despite the difficulties with his injuries, on 28 August 1940, the course was complete. Johnson had 205.25 hours on operational types including 23.50 on the Spitfire.