from test flight. Approaching field, gear down, flaps up, it is seen to execute a flat turn at , sink abruptly and crash. Unprotected fuel tanks in fuselage belly rupture, pilot Rouland and his mechanic perish in fire. Starboard propeller pitch mechanism inadvertently went into reverse on power increase causing loss of control. 7 April Blackburn B-20, V8914, experimental flying-boat with retractable lower-hull, lost after suffering severe aileron flutter – 3 crew killed, 2 rescued by HMS Transylvania. The aircraft's wreck still exists, but remains undisturbed as it is designated a War grave. In 1998, one of the engines was raised as it had been caught in a fishing boat's nets and dragged away from the wreck, into shallower water. It is currently an exhibit in the Dumfries and Galloway Aviation Museum. 11 April Grumman XF4F-2 Wildcat prototype, BuNo 0383, c/n 356, suffers engine failure during test flight out of NAS Anacostia, Washington, D.C., force lands causing considerable damage. Aircraft grounded for several weeks for repairs. 16 April The sole prototype Kimura HK-1 tailless glider, purchased by the Japanese Army, crashes this date after only 13 flights. 24 April Heinkel He 177A V3, wrk. nr. 0000003, D-AGIG, is destroyed in a crash this date. Cause is traced to faulty trimming of the aircraft. 27 April Prototype Yakovlev I-26, first of what became the Yak-1 fighter, crashes, killing pilot Yu. I. Piontkovskiy. The investigation of the crash found that the pilot performed two consecutive barrel rolls at low altitude which was in violation of test flight plan. It was believed that during the first roll, the main landing gear became unlocked, causing it to crash through the wing during the second roll. It has been theorized that Piontkovskiy's deviation from the flight plan was caused by frustration that his aircraft was being used for engine testing while I-26-2, built with the lessons of I-26-1 in mind, was already performing aerobatics. 9 May First prototype Hawker Tornado, P5219, suffers a failure in the monocoque structure just forward of the cockpit while in flight. Test pilot Philip G. Lucas manages to land damaged fighter safely, is awarded the George Medal. Airframe repaired, flying again a month later. 26 May As the British Expeditionary Force retreats to the French coast in the face of German advances, a flight of obsolescent Hawker Hector army co-operation biplanes of No. 613 Squadron RAF is dispatched from RAF