The engine was popping and cutting out during this attack. My speed was reduced to 160 knots, and I was on a course of about 3300. During this run Ensign SPRAGUE was working over the other, unattacked sub. Again he was doing an excellent job, but the enemy AA fire seemed even heavier. On this run, the plane was hit in the left main gas tank at the wing root (It had about 30 gallons in it at the time), tearing a hole about a foot wide and immediately bursting into flames. There were other less effective hits.