 On board, to observe the Friedrichshafen flak defences, was 5 Group's army flak liaison officer, Major Mullock.He estimated that four four-gun batteries of heavy 8.8cm Flak 36s were firing on this one aircraft.Gerry Fawke took evasive action, turning 30 degrees each way every eight seconds while switchbacking up and down 1,000 feet at a time, all on instruments.