13 June 1958, WT477 Canberra T4, BCHU

According to ‘Category Five’ by Colin Cummins:

“The pilot contacted Coningsby after take off and cleared the circuit but no further radio calls were made. Some 55 minutes later the aircraft was seen diving inverted at an angle of 45 degrees and at over 500 knots near Hemswell. The cause could not be established but the turn and slip indicator may have been unserviceable and some other instruments concealed because of the nature of the exercise being undertaken”