operational ceiling (service ceiling)

static ceiling (the highest altitude at which the helicopter is capable of hovering in standard atmosphere) / hover ceiling

service ceiling

combat operational stress control service

operational flight information service

enter operational service

operational service

absolute ceiling (AC)

ceiling (aeronautics)

ceiling lining

ceiling

ceiling altitude

zero ceiling

hover ceiling

static ceiling

low ceiling

minimum ceiling

operating ceiling

unlimited ceiling

smoke ceiling

ceiling in rank

ceiling height

manpower ceiling

personnel ceiling

maximum ceiling

branch (military/service branch, armed service)

separate from active service / the service

Y service (Y-service) / Y-station

regional meteorological service/ regional weather service (RWS)

emergency service / emergency operations service

combat operational stress control (COSC)

common operational picture (COP)

contemporary operational environment / contemporary operating environment (COE)