Complex sentence: The afternoon of the same day, Sub Lieutenants Mearns and Wallis attacked two more Ju 290s, Mearns shooting down 9V + GK piloted by Kurt Nonneberg, which ditched in the sea.
Split into simpler sentences: The afternoon of the same day, Sub Lieutenants Mearns and Wallis attacked two more Ju 290. Mearns shot down 9V + GK piloted by Kurt Nonneberg, which ditched in the sea.