indicates such action is warranted. SE transferred
from a depot or commercial repair activity require
hydraulic fluid sampling prior to transfer.
TRCODETransaction Code or Technical Directive
TSNTime Since New.
TSOTime Since Overhaul.
TURNAROUNDThe time between arriving at a
point and departing from that point.
TURNAROUND CYCLEUsed in conjunction with
vehicles, ships, and aircraft and comprising the
following: loading time at home, planned
maintenance time, and, where applicable, time
TURNAROUND INSPECTIONAn inspection
conducted between flights to ensure the integrity of
the aircraft for flight, verify proper servicing, and
to detect degradation that may have occurred
during the previous flight.
TYPE MAINTENANCE CODEA one-character
numeric or alphabetic code that identifies the type
of maintenance performed.
WSEWeapons Support Equipment.
UAVUnmanned Aerial Vehicle.
UICUnit Identification Code.
nance, other than the fix phase of scheduled main-
tenance, occurring during the interval between
scheduled downtime maintenance periods.
UPKEEPThe preventive, restorative, or additive
work performed on aircraft, equipment, and SE by
the operating units and aircraft SE activities. The
term applies to any method of processing aircraft
required to ensure the completion of standard
operating periods or service tours, including, but
not limited to the servicing, periodic inspections,
functional and bench test, replacement,
preservation, modification, and repair. An upkeep
process extends from the time some of the work is
started until all the work is completed, including
temporary interruptions in direct labor; it also
includes upkeep, evaluation, test, and correction of
discrepancies determined thereby. Upkeep is
divided into two categories: standard and special.
WUCWork Unit CodeA one-, three-, five-, or
seven-character numeric or alpha/numeric code. It
identifies a system, subsystem, set, major
component, repairable subassembly, or part of an
end item being worked on. WUCs are assigned and
controlled by NATEC under the direction of
COMNAVAIRSYSCOM and published in WUC
manuals for end items in three major categories: (1)
T/M/S for aircraft, drones, and missiles; (2) aircraft
flight/tactical trainers; and (3) aeronautical SE. The
system code is the first two positions of the WUC
and is used to identify the system within the
aircraft/equipment on which work is being
performed. These codes are found in the applicable
VIDS/MAFVisual Information Display System/
Maintenance Action FormA multi-purpose
document used in the MDS and VIDS.
ZONAL INSPECTIONA general inspection of a
specific area of aircraft or SE at a scheduled
interval. These inspections are for obvious defects,
such as leaks, frayed cables, cracks, corrosion, or
physical damage. Zonal inspections are normally
performed in conjunction with other scheduled
maintenance tasks by the rating assigned. For
example, an AT rating assigned to perform an
inspection on a radar antenna might also be
assigned a zonal inspection of the entire
compartment for obvious defects.
WD CODEWhen Discovered CodeA one-
character alphabetic code that identifies when the
need for maintenance was discovered.
WEAPON SYSTEMA weapon and those
components/parts required for its operation. (The
term is not precise unless specific parameters are
WEAPONS TEST EQUIPMENTSpecialized
equipment of an electrical or electronic design used
to test, maintain or service aircraft weapons,
bombs, rockets, missiles, special weapons,
torpedoes mines, or any other explosive ordnance.
This equipment is a category of WSE.
WORK CENTER CODEA three-character code
that identifies work centers. They are used in MDR
to identify a work center performing the
maintenance action documented.
WORK CENTER SUPERVISORThe person
assigned the responsibility of maintenance
management within a given work center.
WRAWeapons Replaceable Assembly.