Complex sentence: Even though Scott's engine is hit and losing power, he suddenly drops his landing flaps and is then able to machine-gun "Joe"'s Zero fighter at very close rang when the Zero appears in Scott's cross-hairs.
Split into simpler sentences: Even though Scott's engine is hit and losing power, he suddenly drops his landing flaps. With his speed reduced, Scott is able to machine-gun "Joe" s fighter at very close rang as he flies past and into Scott's cross-hairs.