BACK-TAXI -- BROADCAST [ICAO]
BACK-TAXI- A term used by air traffic controllers to taxi an aircraft
on the runway opposite to the traffic flow. The aircraft may be instructed to
back-taxi to the beginning of the runway or at some point before reaching the
runway end for the purpose of departure or to exit the runway.
BASE LEG- (See TRAFFIC PATTERN.)
BEACON- (See RADAR.)
(See NONDIRECTIONAL BEACON.)
(See AIRPORT ROTATING BEACON.)
(See AERONAUTICAL BEACON.)
BEARING- The horizontal direction to or from
any point, usually measured clockwise from true north, magnetic north, or some
other reference point through 360 degrees.
(See NONDIRECTIONAL BEACON.)
BELOW MINIMUMS- Weather conditions
below the minimums prescribed by regulation for the particular action involved;
e.g., landing minimums, takeoff minimums.
BLAST FENCE- A barrier that is used to divert or dissipate jet or propeller
blast.
BLIND SPEED- The rate of departure or closing of a target relative to the
radar antenna at which cancellation of the primary radar target by moving target
indicator (MTI) circuits in the radar equipment causes a reduction or complete
loss of signal.
(See ICAO term BLIND VELOCITY.)
BLIND SPOT- An area from which
radio transmissions and/or radar echoes cannot be received. The term is also
used to describe portions of the airport not visible from the control tower.
BLIND TRANSMISSION- (See TRANSMITTING IN THE BLIND.)
BLIND VELOCITY [ICAO]- The radial velocity of a moving target such that the
target is not seen on primary radars fitted with certain forms of fixed echo
suppression.
BLIND ZONE- (See BLIND SPOT.)
BLOCKED- Phraseology used to indicate that a radio transmission
has been distorted or interrupted due to multiple simultaneous radio
transmissions.
BOUNDARY LIGHTS- (See AIRPORT LIGHTING.)
BRAKING ACTION (GOOD, FAIR, POOR, OR NIL)- A report of
conditions on the airport movement area providing a pilot with a degree/quality
of braking that he might expect. Braking action is reported in terms of good,
fair, poor, or nil.
(See RUNWAY CONDITION READING.)
BRAKING ACTION ADVISORIES- When
tower controllers have received runway braking action reports which include the
terms "poor" or "nil," or whenever weather conditions are conducive to
deteriorating or rapidly changing runway braking conditions, the tower will
include on the ATIS broadcast the statement, "BRAKING ACTION ADVISORIES ARE IN
EFFECT." During the time Braking Action Advisories are in effect, ATC will issue
the latest braking action report for the runway in use to each arriving and
departing aircraft. Pilots should be prepared for deteriorating braking
conditions and should request current runway condition information if not
volunteered by controllers. Pilots should also be prepared to provide a
descriptive runway condition report to controllers after landing.
BREAKOUT- A technique to direct aircraft out of the approach stream. In the
context of close parallel operations, a breakout is used to direct threatened
aircraft away from a deviating aircraft.
BROADCAST- Transmission of information for which an acknowledgement is not
expected.
(See ICAO term BROADCAST.)
BROADCAST [ICAO]- A transmission of
information relating to air navigation that is not addressed to a specific
station or stations.