Flight Lieutenant Ian Gleed of 87 Squadron wrote about the effect of using the extra boost on the Hurricane while chasing a Bf 109 at low altitude on 19 May 1940: "Damn! We're flat out as it is. Here goes with the tit. A jerk – boost's shot up to 12 pounds; speed's increased by 30 mph. I'm gaining ground – 700, 600, 500 yards. Give him a burst. No, hold your fire you fool! He hasn't seen you yet..." Gleed ran out of ammunition before he could shoot the 109 down although he left it heavily damaged and flying at about .