TTR  Technical Trouble Report 
TTS  Trim Tank System 
TU  Tapping Unit 
TURB  Turbulence, Turbulent 
TURB  Turbine 
TV  Television 
TVBC  Turbine Vane and Blade Cooling 
TVC  Turbine Vane Cooling 
TVOR  Short Range VOR 
TVOR  Very High Frequency Terminal Omnirange Station 
TW  Twisted 
TWLU  Terminal Wireless LAN Unit 
TWR  Tower 
TWY  Taxiway 
TX  Transmission (TCAS to Transponder) 
TYP  Typical 
TYPPLE  Typical Phone Power Level 
T/C  Top of Climb 
T/C  Type Certificate 
T/D  Top of Descent 
T/F  Track of a Fixed Waypoint 
T/R  Thrust Reverser 
ú  Pitch Attitude 
UAC  Upper Area Control Centre 
UADF  User Application Definition File 
UART  Universal Asynchronous Receiver Transmitter 
UD  Upper Deck 
UD  Document Unit ("Unité Documentaire") 
UDC  Upper Deck Cargo 
UDCC  Upper Deck Cargo Compartment 
UDCD  Upper Deck Cargo Door 
UDL  Unit Detail Listing 
UDP  User Datagram Protocol 
UEB  Underseat Electronic Box 
UF  Underfrequency 
UHF  Ultra High Frequency 
UICDL  User Interface Configuration Download List 
ULB  Underwater Locator Beacon 
ULD  Unit Load Device 
ULLI  Understep LED Light 
ULM  Ultra Low Maintenance 
UMS  User Modifiable Software 
UNBAL  Unbalance, Unbalanced 
UNCPLG  Uncoupling 
UNCRCTD  Uncorrected 
UND  Under 
UNIV  Universal 
UNLK  Unlock 
UNLKD  Unlocked, Unlocking 
UNSD  Unused