noun
observation helicopter
A helicopter equipped for surveillance, reconnaissance, or data collection, often used in military, meteorological, or scientific contexts.
気象庁は観測ヘリコプターを使って火山の活動を調べた。
The meteorological agency used an observation helicopter to investigate volcanic activity.
Compound of 観測 (kansoku, 'observation') and ヘリコプター (herikoputā, 'helicopter'), a straightforward technical term.