the Aviation Dictionary

transition height (QFE) triac - -- -- -- - - -- -- -- - -
transition height (QFE) - The height in the vicinity of
an airport at or below which the vertical position of an
aircraft is expressed in height above the airport
reference datum.
transition layer - The airspace between the transition
altitude and the transition level. Aircraft descending
through the transition layer will use altimeters set to
local station pressure, while departing aircraft climbing
through the layer will be using standard altimeter
setting (QNE) of 29.92 inches of Mercury, 1013.2
millibars, or 10 13.2 hectopascals.
transition level (QNE) - The lowest flight level
available for use above the transition altitude.
transition point - A point at an adapted number of
miles from the vertex at which an arrival aircraft would
normally commence descent from its enroute altitude.
This is the first fix adapted on the arrival speed
segments.
transition training - An instructional program designed
to familiarize and qualify a pilot to fly types of aircraft
not previously flown such as tailwheel aircraft, highperformance
aircraft, and aircraft capable of flying at
high altitudes.
transitional airspace - That portion of controlled
airspace wherein aircraft change from one phase of
flight or flight condition to another.
translating cowl - The portion of a turbine engine
cowling that moves back to form an exhaust nozzle for
thrust reverse air.
translating tendency - The tendency of the single-rotor
helicopter to move laterally during hovering flight.
Also referred to as tail rotor drift.
translational lift -- In helicopters, the additional lift
obtained when entering forward flight, due to the
increased efficiency of the rotor system.
translucent - The condition of a material to be
transparent, letting light pass through it but diffusing it
so that objects beyond cannot be seen clearly.
transmission line - A conductor, usually coaxial, used
to join a receiver or a transmitter to the antenna.
transmissivity - Ratio of the amount of power
transmitted through a radome to the amount of power
that would be transmitted with the radome removed.
transmissometer - An apparatus used to determine
visibility by measuring the transmission of light
through the atmosphere. It is the measurement source
for determining runway visual range (RVR) and
runway visibility value (RW).
transmitter - Electric device whose function is to
collect information from one point and send it
electrically to a remote indicator.
transmitting in the blind - A transmission from one
station to other stations in circumstances where twoway
communication cannot be established, but where it
is believed that the called stations can be able to
receive the transmission.
transom - In aviation, the vertical bulkhead at the rear
end of a seaplane float.
transonic flight - Aircraft in flight approximating 0.8 to
1.2 times the speed of sound in air.
transonic speed - The speed of a body relative to the
surrounding fluid that is in some places subsonic and in
other places supersonic; usually from Mach 0.8 to 1.2.
transonic speed range - Generally stated as Mach 0.8
to 1.2 speed range, where some portions of the airfoil
have subsonic flow and others supersonic flow.
transparent - The property of being easily detected or
seen through.
transpiration cooling - Refers to internal cooling air
that exits through porous walls of turbine blades and
vanes.
transponder - Radar beacon transponder. A radar
transmitter-receiver that transmits a coded signal every
time it is interrogated by a ground radar facility.
transponder codes - The number assigned to a
particular multiple pulse reply signal transmitted by a
transponder.
transport category aircraft - An aircraft that is
certificated under FAR Part 25.
transverse pitch - The perpendicular distance between
two rows of rivets. Also referred to as gauge.
transverse wave - A wave that moves in a
perpendicular direction to the direction the wave is
moving.
transverse-flow effect - In rotorcraft, a condition of
increased drag and decreased lift in the aft portion of
the rotor disc caused by the air having a greater
induced velocity and angle in the aft portion of the
disc.
trapezoid - A plane, four-sided geometric figure having
only two sides parallel.
trapped fuel - Undrainable fuel. The amount of fuel
remaining in the system after draining. Trapped fuel is
considered a part of the empty weight of the aircraft.
transmit - In communications, to send information out
traverse - Lying across a body.
from a transmitter. triac - A semiconductor device similar to a
silicon-controlled rectifier that can be triggered by
either a positive or a negative pulse applied to its gate.
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