A helicopter drip pan apparatus for covering and sealing a structural opening in a helicopter. The drip pan apparatus includes a frame member adapted to mount to the structural opening of the helicopter. The frame member has an inwardly-facing peripheral surface extending around the frame member. The frame member and thus the surface have at least one linear portion. A drip pan is selectively affixed to the frame member. The drip pan includes an outwardly-facing peripheral groove which extends around the outside edge of the drip pan. Like the surface of the frame member, the groove has at least one linear portion. The perimeter of the drip pan conforms to the surface of the frame member. A seal member is disposed in the groove of the drip pan to sealingly engaging the surface of the frame member against fluid leakage therethrough.