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Pilot/Controller Glossary

3/29/18

PCG B

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B

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 AERONAUTICAL BEACON.)
(See AIRPORT ROTATING BEACON.)
(See AIRWAY BEACON.)
(See MARKER BEACON.)
(See NONDIRECTIONAL BEACON.)
(See RADAR.)

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.

BLAST PAD

− A surface adjacent to the ends of a

runway provided to reduce the erosive effect of jet
blast and propeller wash.

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.

BOTTOM ALTITUDE– In reference to published
altitude restrictions on a STAR or STAR runway
transition, the lowest altitude authorized.

BOUNDARY LIGHTS

(See AIRPORT LIGHTING.)

BRAKING ACTION (GOOD, GOOD TO MEDI-
UM, MEDIUM, MEDIUM TO POOR, POOR, OR
NIL)

  A report of conditions on the airport

movement area providing a pilot with a degree/quali-
ty of braking to expect. Braking action is reported in
terms of good, good to medium, medium, medium to
poor, poor, or nil.

(See RUNWAY CONDITION READING.)
(See RUNWAY CONDITION REPORT.)
(See RUNWAY CONDITION CODES.)

BRAKING ACTION ADVISORIES

− When tower

controllers receive runway braking action reports
which include the terms “medium,” “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 most
current 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 issued 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 simultaneous
(independent) parallel operations, a breakout is used
to direct threatened aircraft away from a deviating
aircraft.