It was very common for fighters to have gun cameras to confirm kills. Usually they'd start recording when the guns fired, but in some instances the pilots could activate them whenever. Otherwise there would be confirmation of a kill from a wingman, an observer on the ground, or even sometimes the enemy.
In this instance, I'm sure there would be physical evidence as well, such as bits of Japanese plane stuck in the engine cowling!
GracefullyIgnorant t1_jcr9c4u wrote
Reply to comment by anhedonis539 in TIL that in WW2, a Marine Corps Corsair pilot used his propeller to chew off the tail of an enemy aircraft after his guns jammed, while under fire from the enemy plane's tailgunner. The enemy plane crashed but the Corsair pilot made it back to base, receiving the Navy Cross for his actions. by hipster_deckard
It was very common for fighters to have gun cameras to confirm kills. Usually they'd start recording when the guns fired, but in some instances the pilots could activate them whenever. Otherwise there would be confirmation of a kill from a wingman, an observer on the ground, or even sometimes the enemy. In this instance, I'm sure there would be physical evidence as well, such as bits of Japanese plane stuck in the engine cowling!