Aerospace Acronyms: U
| Acronym | Definition |
|---|---|
| UAS | University Air Squadron. |
| UDF | UHF Direction Finding. |
| UFN | Until Further Notice. |
| UHF | Ultra-High Frequency. Radio frequencies in the 300-3,000 MHz band. |
| Unicom | Privately-operated advisory A/G radio service at uncontrolled airfields (USA). |
| UNL | Unlimited |
| U/S | Unserviceable (i.e not working) when applied to an aircraft or its equipment. |
| UTC | Co-ordinated Universal Time, formerly Greenwich Mean Time. |
