Complex sentence: The aircraft flew on 22 December 1930 with Mikhail Gromov at the controls and with ski landing gear, despite almost crashing owing to vibration causing the throttles to close, the test flight was a success.
Split into simpler sentences: The aircraft flew on 22 December 1930 with Mikhail Gromov at the controls and with ski landing gear. Despite almost crashing owing to vibration causing the throttles to close, the test flight was a success.