artillery observation plane

plane of rotation / tip path plane

plane-to-plane communication

tip path plane / plane of rotation

observation point / observation post (OP)

artillery fire direction plane

forward observer (FO), forward observation officer; (artillery) observer / spotter

artillery observation post

artillery observation unit

field artillery observation battalion

forward artillery observation point

anti-aircraft artillery observation aircraft

artillery group observation post

artillery groupment observation post

artillery instrumental observation

artillery observation

artillery observation aeroplane

artillery observation aircraft

artillery observation helicopter

artillery observation post vehicle

artillery observation tank

artillery observation tower

artillery observation vehicle

artillery reconnaissance and observation

forward artillery observation post

mobile artillery observation post

vehicle-mounted artillery observation post

artillery forward observation officer

main artillery (major caliber artillery)

artillery and rocket artillery

attack plane

diving plane

float-type plane