u

UA

UART

UASC

UAT

UAV

UB

UBI

UCI

UCS

UD

UDP

UF

UFAX

UFCP

UFDR

UHD

UHF

UI

UIR

UL

ULB

ULD

ULLAGE

ULTRASONIC

ULTRAVIOLET RADIATION

UM

UMBILICAL CORD

UMI

UML

UMS

UMSDT

UMT

UNC-LCS

UNDUCTED FAN

UNLK

UNPAIRED CHANNEL

UNS

UOS

UOT

UP

UPA

UPG

UPLINK

UPLK

UPPER-AIR-OBSERVATION

UPR

UPRM

UPS

UPSMS

URA

USA

USAF

USB

USEC

USER

USPV

USTB

UTC

UTE

UTIL

UTM

UTP

UUT

UV

UW

UZLIM