Complex sentence: On 7 April, during a test run, the aircraft experienced extreme vibration due to aileron flutter and the crew bailed out, three were lost the other two were picked up by, a converted merchantman.
Split into simpler sentences: On 7 April, during a test run, the aircraft experienced extreme vibration due to aileron flutter and the crew bailed out. Three were lost, the other two were picked up by, a converted merchantman.