U
- UAS
- Unmanned Aircraft System, another name for a drone
- UAV
- Unmanned aerial vehicle
- UAVNZ
- The UAV (drone) division of the Aviation Industry Association of New Zealand.
- UMS
- Unattended Machinery Space
- Unanticipated yaw
- Uncommanded yaw of a helicopter that is not linked to any failure and is not related to full loss of tail rotor thrust
- UNCLOS
- United Nations Convention on the Law of the Sea
- Uncontrolled class G airspace
- Under ICAO Annex 11 and New Zealand Civil Aviation Rules Part 71 – Designation and Classification of Airspace, airspace is divided into seven classifications: classes A to G. Class G is uncontrolled airspace.
Classes B, E and F are not available in New Zealand
- Under-keel Clearance
- Minimum distance between the keel and seabed
- Underway
- When underway, a vessel is no longer secured to a wharf, a seabed or any other stationary object.
- UNICOM
- UNICOM Service means a ground radio communications service in the aeronautical mobile service providing local aerodrome information for the facilitation of aviation, and, for the avoidance of doubt, a UNICOM service is not an air traffic service (see CAR 1 Definitions and Abbreviations; for further information see Appendix 3).
- Unmooring
- A procedure to release and cast off the lines of a vessel from the fixtures to which it is moored
- Unrigging
- To stow away equipment
- Unshielded operation
- A shielded operation (or shielded flight) is one in which a drone remains within 100 m of, and below the top of, a natural or man-made object: for example, trees, a building or tower. When flying shielded it is permissible to fly at night and also to fly within controlled airspace without Air Traffic Control clearance. This is because other aircraft are unlikely to be flying so low and close to structures.
- UP direction
- Trains running towards Otiria in the North Island and towards Picton in the South Island are travelling in the UP direction
- Up main line
- A portion of rail track on a multiline rail network on which trains are run in the up direction.
- Upper sheave
- A grooved pulley. The engine drives the upper sheave with multiple pulley belts.
- UPS
- Uninterruptable power supply
- Upwind leg
- A flight path parallel to the landing runway in the direction of landing.
- UTC
- Universal Time Coordinated