Pilot/Controller Glossary

4/3/14

PCG B−1

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, FAIR, POOR, OR
NIL)

−  A report of conditions on the airport

movement area providing a pilot with a degree/

quality of braking that he/she 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 “fair,” “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” on the ATIS broadcast. 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.)