A drip pan apparatus for a “M” model BLACK HAWK® helicopter and the like includes an expanded corner structure for accommodating an access port also positioned further outwardly in the corner than in prior drip pan apparatuses, facilitating filter viewing while retaining peripheral o-ring seal. An expanded corner of the airframe skirt is accommodated by the expanded corresponding corner of a frame, which also defines a small radius internal curve. The removable pan has a small radius curve cooperating with the small radius curve of the frame and is sealed thereto by the peripheral o-ring seal sealing the entire pan to the frame. Physical access to the filter is enhanced.