1-100

aft

an adjective referring to the back part of a plane. Rear is also used with the same meaning. It contrasts with forward. The words before and after are only used to talk about time relationships

A.C.

Alternating Current: the type of electrical power generated by the engine generators and characterised by frequency oscillation as opposed to D.C. (Direct Current).

a/c

abbreviation for aircraft

abeam the runway

indicating that the runway is to the side of the aircraft, at a bearing of approximately 90° or 270° relative to the aircraft, i.e. to the right or the left

abort (v)

to stop doing something or stop a process that you had intended to do or had already started to do, especially a take-off or landing: take-off must be aborted before V1.

ACAS

Airborne Collision Avoidance System: an aircraft system using Secondary Surveillance Radar (SSR) transponder signals, which operates independently of ground equipment to alert the flight crew about conflicting aircraft

A.C. bus

an aircraft electrical power distribution point for alternating current to which several power circuits are connected

AC Essential feed

the main alternating current power supply

access platform

a platform mounted on wheels with steps which allows technicians to gain access to the higher parts of the aircraft

accretion rate

the speed at which ice is accumulating; it is also referred to as the accumulation rate or build-up rate

acknowledge (v)

to say that you have heard and understood. Requesting and providing clarification, paraphrasing, confirming and acknowledging all play a key role in such exchanges: In case of radio failure, acknowledge by flashing headlights.

acrid

used to describe a sharp, bitter (smell), especially of smoke or fumes

acute

"1) at a sharp angle, at an angle of less than 90° 2) severe: acute pain"

ADF

Automatic Direction Finder: airborne radio navaid tuned to non-directional beacons; the intersection of two bearings provides the aircraft’s position: if the ADF needle points up, the NDB is ahead

advance (v)

to move forward the thrust or throttle levers to increase engine power; the contrary of to retard: advance the thrust levers to TOGA (Take-off / Go-around)

Advanced Visual Docking Guidance System

another term for the Nose-in Guidance System or PAPA (Parallel Aircraft Parking Aid). Different technologies are used, but basically they all use a system of lights to guide the crew to the correct position for their aircraft type

advise (v)

most often used in aviation in the sense of to inform or to tell, rather than to recommend: advise intentions

advisory

information displayed to the crew which does not require immediate action or informational documents issued by the regulator or the manufacturer

aerodrome

any place from which aircraft flight operations take place

affect (v)

to have an effect or influence on something or someone: It is well known that fatigue affects a pilot’s alertness and performance

affirm

yes: ‘Confirm 8.33.’ – ‘Affirm. 8.33.’

against

"1) in relation to, compared with: the airspeed against angle of attack ratio was a concern 2) in contact with: the aircraft overran the end of the runway and came to a stop against the boundary fence."

AGNIS

Azimuth Guidance for Nose-In Stand: one of the most popular forms of stand guidance, i.e. ways of guiding a plane to its correct position in the stand

ahead

in front of the aircraft: there is traffic ahead at 10 o’clock.

ahead of the aircraft

a desirable condition meaning that the flight crew can anticipate what the aircraft will do and what they should plan for in advance: the crew must stay ahead of the aircraft at all times.

aileron power control unit

a hydraulically powered servo-control which moves the ailerons on the outer wings

air conditioning pack

a large unit comprising an air cycle machine and pre-cooler which regulates bleed air from the engine compressor for use in conditioning the cabin air

Air Data Computer

ADC: a digital computer serving as a central source of information on the surrounding atmosphere and the aircraft flight through it. It provides the data to the automatic flight control system, the flight instruments and other systems.

Air Safety report

a report written after an operational incident. Transparent, non-blaming reporting of incidents contributes significantly to improvements in safety and a better understanding of error chains

airborne

"1) in the air 2) installed or carried on the aircraft: The ADF is an airborne navaid"

airbridge

a telescopic walkway for passengers to board and disembark from the aircraft directly from and to the terminal building; it is also referred to as a jetway or jetty

aircraft maintenance technician

AMT: an aircraft mechanic or engineer who inspects and services the aircraft (engine oil levels, tyre pressure and wear etc.), performs any small repairs and makes entries in the aircraft technical logbook. These activities are line maintenance

airframe

another word for the aircraft structure or fuselage and wings; hull is also used

AIRPROX

a situation in which the distance between aircraft and their relative positions and speed is such that their safety may be threatened. After such an incident a pilot or ATCO can file a report.

airstairs

mobile stairs used at outlying stands for passengers to board and disembark

ALAR

Approach and Landing Accident Reduction: more accidents occur during approach and landing than during any other phase of flight. The Flight Safety Foundation has gathered extensive research on this issue and published the ALAR Tool Kit.

alternate (n)

an airport along or near the scheduled route to which the aircraft can divert and where it can land in case of an incident during the flight

alternative

something you can choose to do instead of something else. It can be related to any aspect of the flight: routing, level, heading, timing etc: We have two alternatives: uplift extra fuel or offload the last passengers.

altimeter setting

standard pressure altitude with reference to sea level (QNH) or local pressure altitude at the airport elevation (QFE) set by the crew on their altimeter and critical, especially during descent and approach: The altimeter setting is 1023. Confirm.

altitude restriction

an obligation for the crew to not fly above or below a certain altitude at a given point or in a given area

amber transit lights

the amber lights neat the landing gear lever which are illuminated when the landing gear is moving between its extended and retracted positions and vice versa

ambient lighting

the general lighting of the cockpit provided by the dome light

amend (v)

to modify or change something: We wish to amend our flight plan.

AMT

See 'aircraft maintenance technician'

analog(ue)

technology based on continuous variables rather than digital binary inputs: Most analog(ue) instruments have been replaced by digital displays.

angled exit / turn-off

exits designed to facilitate aircraft vacating the runway at speed, hence the term high-speed turnoff, and performing a rolling start for take-off

angle of attack

AOA or á: the angle between the chord line of the wing of an aircraft and the vector representing the relative motion between the aircraft and the atmosphere. Information from the angle of attack sensor, or alpha probe, is used to trigger a stall warning

anomaly

an unusual, incorrect or abnormal event: we experienced an oil pressure indication anomaly on Engine Number 3.

ANSP

Air Navigation Service Provider: organisation providing air traffic control within a given region for example, Aerothai, Airways NZ, DFS, FANA, FAA, NAV Canada, NATS, PANSA, ENAV etc.

anti-ice / anti-icing

all the pneumatic systems which prevent the accumulation of ice on the wing leading edges and engine air intakes: wing anti-ice, engine anti-ice

Antonov

Russian aircraft manufacturer. The Antonov 124 and 225 are currently among the world’s largest cargo aircraft; the Antonov 225 has a maximum take-off weight of approximately 600 tonnes

approach charts

instrument approach charts show holding procedures, instrument approach procedures and missed approach procedures. In addition to the plan and profile views of various instrument procedures, the charts provide a wealth of other information

Approach Control frequency

the frequency used by the Approach controllers at a given airport as distinct from the Tower or Ground frequencies

approach gate

an imaginary point used as a basis for vectoring the aircraft to the final approach course

approach segments

the parts of an instrument approach: arrival, initial approach, intermediate approach, final approach and missed approach segments

apron

the paved area around the terminal buildings, hangars and cargo terminals where aircraft park

APU

Auxiliary Power Unit: a small gas turbine engine, usually located in the tail cone, which is used on the ground when the engines are shut down to generate electricity, to provide air conditioning and high pressure air to start the engines.

aquaplaning

when an aircraft’s wheels are partially supported by standing water on the runway and not fully in contact with the runway surface so that braking and steering are inefficient

arc

the ground track of an aircraft flying a constant DME distance from a navaid to intercept the ILS localizer inbound course. The DME arc is often used to transition from en route to intermediate approach.

Are you visual?

‘Have you got the runway in sight?’

Area Control (Centre)

ACC: ATCOs responsible for planes overflying a large area of airspace en route at altitude

area navigation

RNAV: area navigation allows pilots to fly on a direct course using, but not actually overflying, groundbased radio aids. LORAN-C and GPS are forms of area navigation.

arm (v)

to place a device in an active mode so that it is ready to operate: arm the Vertical Speed mode on the FCU / MCP; the cabin attendant armed the escape slide

asap

as soon as possible: immediately, very quickly

assess (v)

to evaluate: After a major failure, the crew must assess the situation

assigned level

the flight level to which a flight has been cleared by ATC

asymmetry

unequal position or force on the two sides of the aircraft; flap asymmetry, asymmetric thrust

ASU

Air Start Unit: ground support vehicle which compresses air and delivers it to the aircraft engine if the APU is not available

at time

mentioned prior to a given time to avoid confusion with any other value: request descent at time 45

ATIS

Automatic Terminal Information Service: a continuous broadcast of recorded information in selected high-activity terminal areas, e.g.: “Hong Kong Arrival Information Kilo at 17:05Z; Runway 07 closed for maintenance; Wind 340°, 15 knots; Visibility 8 km”

ATR

a twin-engine turboprop regional transport manufactured by a consortium of Alenia Aeronautica and EADS. There are two versions: the ATR 42 and larger ATR 72.

attitude

the position of the aircraft in relation to the three axes: pitch, roll and yaw. Attitude is conventionally displayed on the Attitude Director Indicator (ADI) or artificial horizon, now often incorporated into the Primary Flight Display (PFD).

audio warning

a standardised sound (repetitive chime, single stroke chime, clacker, cavalry charge, woofer) which draws the crew’s attention to an anomaly: the ENG 1 red fire warning light came on accompanied by the repetitive chime audio warning.

autobrake

a computer-assisted system which controls and monitors landing gear brake applications in order to achieve maximum braking efficiency: the PF selects an autobrake MIN, MED or MAX setting according to the runway conditions.

auto-flight system

AFS: the combination of autopilot, autothrottle / autothrust, flight director, autoland systems etc. used to control the flight through the Flight Management System (FMS)

autoland

an autopilot function which enables the aircraft to be landed automatically. ILS installations now often support fully automatic “hands-off” autoland approaches to below 50 feet above the runway threshold in visibility, or RVR as low as 200 metres or less

Automatic Direction Finder

ADF: a flight instrument which indicates the direction from which the signal from a non-directional beacon is coming, i.e. a relative bearing

Autopilot

AP: a computerised system which provides the flight controls with orders: The FAA wants new software installed on Boeing 777s to prevent crews from inadvertently engaging the autopilot before takeoff.

autothrottle

ATHR, an automatic engine power control system: When using the autothrottle during autoland, position command speed to VREF +5 knots

autothrust

computerised system which provides the engines with orders: The autothrust was disconnected by the PF to prevent another overspeed conditon

aviation English

Aviation English is broader than ICAO phraseology, but it is the language used by pilots and controllers in an operational context. In the ICAO context, fuel prices, low-cost airlines, aerobatics or the four forces of flight are not Aviation English.

avionics bay

the under-floor avionics compartment where computers and other electronic equipment are located (Airbus). Boeing call this compartment the main equipment centre.

avoidance

the action of distancing oneself from an obstacle, danger etc

avoiding action

an announcement by the controller to alert the crews that they must modify their flightpath to avoid coming into conflict with other traffic

axle

a shaft on which one or more landing gear wheels are mounted

back course

a procedure when a reverse ILS localizer signal can be used for an approach

backtrack (v)

having landed on the runway in use, to turn 180° and proceed along the runway in the opposite direction or having entered the runway lower down, to taxi to the end of the runway and turn 180° in order to have a longer take-off run: backtrack Runway 27R

baggage cart

small towed vehicle for transporting baggage

bank (n)

angle at which the aircraft is inclined about its longitudinal axis: bank angle, turn and bank indicator

base leg

the part of a conventional landing circuit when the aircraft turns off the downwind leg and flies perpendicular to the extended runway centreline before joining the glidepath

base turn

a specified outbound track followed by a turn of more than 180° to intercept the inbound track

bearing

"1) the angular direction of a distant point measured in degrees clockwise from a local meridian or other reference 2) a surface that supports and reduces friction between moving parts. Types of bearing include ball, roller and needle bearings"

BECMG

becoming (METAR): BECMG 0812/0815 21015KT PROB30

belligerent

aggressive, rude, provocative, violent: the cabin crew are dealing with some very belligerent football fans who are abusing the other passengers

belt conveyor

baggage loader with rotating rubber belt used to load the bulk cargo compartment, hold 5

below minima / minimums

being below the limits of vertical and horizontal visibility for which the airport, aircraft and crew are certificated

best practice

technique, procedure or process regarded as most efficient and appropriate: all training should adopt best practice

bird strike

impact by a bird. Birds can hit the aircraft at different points. Effects will depend on the location of the impact and the size and number of the birds. The ingestion of large birds may cause engine stall or failure.

black-hole effect

spatial disorientation and erroneous perception of altitude caused by a dark approach area and bright lights beyond the active runway

blade

a radial aerofoil designed to rotate about an axis: the bird ingestion caused some minor damage to the fan and 2nd stage LP compressor blades