noun
antisubmarine patrol plane
Military term for a fixed-wing aircraft used to detect and track submarines.
海上自衛隊は新しい対潜哨戒機を導入した。
The Maritime Self-Defense Force introduced a new antisubmarine patrol plane.
哨戒機 is a general patrol aircraft, while 対潜哨戒機 specifically targets submarines.
Compound of 対潜 (antisubmarine) + 哨戒機 (patrol aircraft).