Torpedo-carrying Swordfish needed an auxiliary tank in the observer's compartment because the torpedo occupied the external mounting position. Aircraft carrying bombs could use a tank beneath the fuselage instead. The internal tank displaced the observer into the rear gunner's seat, where he also had to man the machine gun. Leaking fuel collected in the rear cockpit, exposing him to an additional fire risk while tracer ammunition was fired from the aircraft and at it.
Notable Point · 51:27-53:30
An internal fuel tank displaces the Swordfish observer
The torpedo load forced extra fuel into the observer's seat, leaving the observer to work the rear gun beside a leaking tank.