Aviation Glossary

ADF Automatic Direction Finder in Cessna 172 VH-KPR Automatic Direction Finder. If tuned to the frequency of a radio transmitter it will point towards that transmitter. Normally it would be tuned to a navigational beacon, or NDB, but it can also be tuned to a public broadcasting station in the AM frequency band (200-1655kHz). For example, 2RN (Radio National) is 702kHz and is located south-west of Bankstown. This should be used with caution as some transmitters are simply repeater stations, so you may be heading towards one of those instead of the main tower.
The ADF can also be used to receive the ATIS. See lesson 27 for an example of this secondary usage.
Of Curtis Aviation's Citabrias, WKM has an ADF; RRW and MWY don't. See Cessna 172 cockpit for an example fitted to a Cessna 172.
AFRU Aerodrome Frequency Response Unit
A device installed at many non-towered aerodromes to assist pilots' awarenesss of an incorrectly-selected VHF frequency. More detail in lesson 49 - first solo flight post-GFPT.
AGLAbove Ground Level (as opposed to AMSL). Heights in the regulations are usually quoted in feet AGL, eg normal circuit height (and minimum height above built-up areas) is 1000' AGL; minimum height above ground is 500' AGL. (Legal aside: height is measured above the ground, or any object on it, within a radius of 600 metres from a point vertically below the aircraft.)
AHArtificial Horizon. More commonly known now as Attitude Indicator.
AI Attitude Indicator in Cessna 172 VH-KPR Attitude Indicator. The prime source of attitude information in instrument flight. The mechanism is a gyro, driven by suction. Attitude Indicator mechanism The face is marked with bank angles at 0°, 10°, 20°, 30°, 60° and 90°, and pitch angles at -20°, -10°, 0°, +5°, +10° and +15°.
When flying on instruments, the AI should be checked every few seconds.
See Cessna 172 cockpit.
ALAAuthorised Landing Area. An airstrip that doesn't meet the requirements of an airport. Local examples: The Oaks, Wedderburn, Yerranderie and the narrow gravel strip by the pipeline to Prospect.
ALAP Work cycle in flight:
Note that three of the four items require the pilot's focus to be outside the cockpit. Introduced in lesson 3 - Straight and Level Flight. Reintroduced in lesson 28 - Advanced turning as a constant reminder during climbs and steep turns.
ALP Work cycle on final approach:
Aim point
Introduced in lesson 9 - Circuits.
Altimeter Altimetert in Citabria VH-RRW An instrument used to measure pressure, which is displayed as height above a fixed level, usually Mean Sea Level. Attitude Indicator mechanism The mechanism is a sealed aneroid capsule inside a container open to the outside pressure via a static vent. It reads like a clock, with markings every 20 and 100 feet ('minute' hand) or 200 and 1000 feet ('hour' hand). A subscale is set to local or area QNH so that all aircraft in the area are displaying consistent heights.
See Wikipedia - Altimeter.
AMSLAbove Mean Sea Level (as opposed to AGL). Circuit heights for individual aerodromes are in feet AMSL, eg Camden is 1300' AMSL; incoming traffic should be at 1800' AMSL.
ANCA reminder by instructors to keen students that the priorities when flying a plane are Aviate, Navigate, Communicate. So, for example, radio calls should not interfere with keeping the plane flying smoothly. Also relevant in an emergency, eg if the engine fails, establish a best-rate glide before making a mayday call.
AoAAngle of Attack. The angle between the chord line of the wings and the relative airflow. Flying at a high angle of attack risks bringing on a stall.
APST Procedure for levelling out after a climb:
Lower the nose first and allow the plane to accelerate to cruising speed before reducing the power. This way you won't experience the sinking feeling that results if you reduce the power first. Introduced in lesson 4 - Climbing and Descending.
ARNAviation Reference Number. Issued to each prospective pilot by CASA.
ASI Air Speed Indicator in Citabria VH-RRW Air Speed Indicator. Measured in knots (KIAS). The mechanism is a bellows fed by dynamic pressure from a forward-facing pitot tube, inside a sealed aneroid chamber fed from the static vent. Air Speed Indicator mechanism The green arc shows normal operating range (up to VNO). The white arc shows the flap operating range (the maximum speed at which flaps can be extended is VFE). The red line shows the 'never exceed speed' (VNE)
ATCAir Traffic Control, AKA "The Tower". Eg Camden Tower is 120.1MHz; Camden Ground 129.1MHz; Sydney Radar is 124.55.
ATISAutomatic Terminal Information Service - Recorded weather and aerodrome information, updated by tower staff throughout the day. At Camden the ATIS frequency is 125.1MHz.
AWISAutomatic Weather Information Service - Recorded weather information by phone, updated throughout the day. At Camden the AWIS number is 02 4655 9248.
AWSAutomatic Weather Station.
BAKBasic Aircraft Knowledge. A multiple-choice theory test that has to be passed before the student pilot can sit the GFPT flight test. Colloquially, Bob Tait's book covering the material tested in the BAK test.
BEWBasic Empty Weight.
BRoCBest Rate of Climb (VY). 60 knots in the Citabria, but we use 70 in practice. 76 knots in the PA-28 Warrior.
BUMFISH Downwind checks to ensure the aircraft is in a fit state to land:
Brakes OFF (apply them briefly, then heels back on the floor)
Undercarriage DOWN (or, on a Citabria, wheels still attached to the airframe)
Mixture - FULL RICH
Fuel - ON (including the electric fuel pump in aircraft such as the Warrior)
Instruments/Indications - NORMAL (especially oil temperature and pressure)
Switches - ON (ie both magnetos)
Hatches and harness -SECURE
See lesson 9.
CASACivil Aviation Safety Authority. The Australian Government body responsible for the safety of civil aviation, including aircraft registration, licencing of pilots and implementation of a safe National Airspace System (NAS). See CASA's web site for more information.
CAVOKCloud And Visibility OK in a weather report or forecast. Pronounced CAV-O-KAY.
CCHAT Procedure for making changes to the power setting:
See lesson 3 - Straight and Level Flight and lesson 5 - Climbing and Descending.
CFITControlled Flight Into Terrain. You do not want to do this, but it seems to happen with depressing regularity, often at night or in cloud.
CFMOST Checks following engine failure:
Carby heat HOT
Fuel ON, and fuel in tanks (check gauges)
Mixture - FULL RICH
Oil temperature and pressure in the green (if in the red, there's not much point trying to restart the engine)
Switches - ON (try each magneto in turn)
Throttle - through the range and back to 1/3 (so you can tell if it restarts, but not so much as to cause problems if it suddenly restarts on short final)
See lesson 27 - Practice Forced Landings.
CGCentre of Gravity.
CTAConTrolled Area, usually around an airport.
CTAFCommon Traffic Advisory Frequency. The radio frequency used to make position broadcasts at non-towered aerodromes. Some aerodromes have their own frequency. For example, Camden's is, unsurprisingly, the same as the Tower: 120.1MHz. Other (generally smaller) airfields share the same frequency - 126.7MHz.
DGDirectional Gyro. Another name for the DI. Also known as a Magnetic Compass.
DIDirection Indicator in Citabria VH-WKMDirectional Indicator. Another name for the DG. Also known as a Gyrocompass. Unlike a magnetic compass, it remains steady and unaffected by acceleration or turning errors. However, also unlike the compass, it has no way of actively seeking north or any other direction, so it needs to be aligned with the compass before take-off and every 15 minutes during a flight. That's what the knob at bottom left is for.

Like the AI, it's powered by the aircraft's vacuum system.
DMEDistance Measuring Equipment. Radio equipment used to display an aircraft's distance from a ground station. DME refers to both the ground-based and aircraft-mounted components of the system.
EFATOEngine Failure After Take Off. This rarely happens, but when it does you need to be ready, and make the right decision, because it could be your last. In the Citabria, adopting a gliding attitude at 60kts is a good first step; further action depends largely on your height above the ground, but a steep turn is probably going to be lethal. It was lesson 19 before we got round to this drill.
ERSAEn Route Supplement Australia. A bit of light reading for bedtime that contains information on all Australian Aerodromes and much else besides. Pilots are expected to keep a current copy in the aircraft.
FAI Flight Attitude Indicator. See Attitude Indicator.
FISFlight Information Service, otherwise known as Flightwatch.
GAGeneral Aviation (ie small planes, private pilots).
GAAPGeneral Aviation Aerodrome Procedures. The business of operating from an aerodrome under Air Traffic Control. It covers arrival and departures, altitudes, restrictions and radio procedures.
GFPTGeneral Flying Proficiency Test. An intermediate stage to a PPL. Allows a pilot to fly as pilot in command in the student pilot training area (subject to approval by an instructor), and to carry passengers. See CASA stages for more information.
GNSSGlobal Navigation Satellite System. Generic term covering GPS and the equivalent Russian system - GLO-NASS.
GPSGlobal Positioning System. The US version of GNSS. Fast becoming a commodity for everying from mountain biking to aviation.
HASELL Pre-aerobatic checks (before steep turns, stalls and the like):
Height (Must recover from manouevres by 3000 feet AGL. 4500 feet is normal.)
Airframe (clean, ie flaps up)
Security (harness, no loose objects)
Engine (instruments in green)
Location (not over a heavily built-up area)
Lookout (minimum 180° and preferably a 360° turn)
Introduced in lesson 7 - Stalling. Revised in lesson 28 - Advanced turning.
HFHigh Frequency. The (freq?) radio band used for long-distance communication in remote areas. In the outback, HF comes into its own as it follows the earth's curvature so has a longer range.
HSHS Work cycle on downwind leg of a circuit:
Heading is towards your chosen reference point, speed is 90-95kt in the Citabria, height is usually 1000 feet above ground level (which translates to 1300ft AMSL at Camden, which is at an elevation of 230 ft) and spacing is the distance on the runway, measured by lining up part of the wing (eg the jury strut) with the centreline of the runway. See lesson 9.
hPahectoPascals. SI standard unit of pressure. Conveniently, the same as millibars (mb).
IFRInstrument Flight Rules. The rules and regulations covering the use of instruments, eg when flying in cloud or at night. Not "I Fly by Road"...
IMCInstrument Meteorological Conditions. Weather conditions requiring flight by IFR.
ISA International Standard Atmosphere. Assumes a pressure of 1013.25 hPa and a temperature of 15°C at sea-level. As you go up the pressure is assumed to decrease at 1 hPa per 30 feet, and the temperature at 2°C per 1000 feet.
KIASKnots Indicated Airspeed. Often abbreviated to 'kt' or 'kts'.
LAMELicensed Aircraft Maintenance Engineer.
LFLow Frequency. The 30-300kHz radio band, used by navigational beacons and public broadcasters.
MAUWMaximum All-Up Weight.
MBZMandatory Broadcast Zone. Now superseded by CTAF(R). An area where you are not allowed to operate unless carrying and using a radio.
METARMeteorological Aviation Report (I'm guessing here). Weather report for a particular location.
MFMedium Frequency. The 300-3000kHz radio band, used by navigational beacons and public broadcasters.
MRMaintenance Release. A document signed by a LAME basically indicating that the aircraft is safe to fly. It records the type, registration, date of and engine hours till the next service (in a training aircraft the hours will likely trigger the service before the date), and any required maintenance items. It's one of the three documents that must legally be carried on a flight, the other two being the pilot's licence (and medical) and current charts relevant for the flight.
MTOWMaximum Take Off Weight.
NASNational Airspace System. The rules and regulations to ensure that aircraft can share the air without bumping into the ground or each other. See CASA's website. Dick Smith's website is also relevant (if controversial).
NDBNon Directional Beacon. A source of radio signals that can be identified and homed onto by an ADF. NDBs operate in either the low frequency (30-300kHz) or medium frequency (300-3000kHz) bands. Typical frequencies are between 200 and 430kHz. Camden is 281kHz.
NDVNon Directional Visibility. In a TAF, means that visibility has been measured in a single direction only. See TAF example in lesson 6.
NMNautical Mile. Unit of distance used in aviation. One nautical mile is a second(?) of longitude at the equator. 1nm = 1.15 statute miles or 1.85 kilometres.
ONUS Effect of turning on a magnetic compass:
This effect means that when you're turning towards north, you need to continue around 15° past your intended heading, and when turning south, you should roll out 15° before your intended heading.
Introduced in lesson 31 - Basic Instrument Flight 1. See also: SAND.
PAST Procedure for entering a climb or descent, or levelling out after a descent.
Introduced in lesson 4 - Climbing and Descending.
P-factor Propellor factor. In a tailwheel aircraft, when the tail is down at the start of the take-off roll, the angle of attack of the right propeller blade is greater than the left (for clockwise rotation). This contributes to the tendency of the aircraft to head left, but only until the tail is raised. With the tail level and the thrustline straight ahead, the p-factor disappears.
See lesson 9 - Circuits
PFLPractice Forced Landing.
Piano KeysWhite longitudinal stripes on the runway, marking the beginning of the landing area. It's normally bad form to put the aircraft on the ground before you reach these markings (although forgiveable in certain situations, eg real or simulated engine failure).
PICPilot In Command. Where you're in charge of the aircraft, practically and legally. A student's flying hours are divided into Dual and in Command.
POHPilot's Operating Handbook. The bible on each aircraft you fly, wherein you will find a whole load of stuff specific to this aircraft, like stall speeds, loading charts, performance graphs and procedures for normal operation and emergencies. These must be memorised and followed.
PPLPrivate Pilot Licence. Allows the holder to commit aviation anywhere in Australia and (presumably with further paperwork, check flights etc) the world. smile
QNHQuestion Nil Height. Pressure at sea-level at this location, measured in hectoPascals (hPa). If all aircraft in a particular area set their altimeters to read the same QNH, then their relative heights will be accurate. This is essential for vertical separation and therefore safety. The 'Q' codes originated in World War Two (or possibly WW1) when radio operators used morse code so brevity was a virtue. Actually, it still is.
Rate-one turn Turn co-ordinator in Citabria RRWIn a rate-one turn the aircraft changes its heading at 3° per second. Therefore a 180° turn will take one minute and a 360° turn will take two minutes. The turn indicator has markings for a (correctly balanced) rate 1 turn and shows '2 min' as a reminder of how long it takes.
To calculate the bank angle for a rate one turn, divide airspeed by 10 and add half the answer. For example: At 80 knots, the bank angle is 12°.
At 100 knots, it's 15°.
At 120 knots, 18°.
You can also calculate your turn radius if you hold a constant rate. At 100 knots, the circumference of the circle flown is 3.33nm. Dividing by pi gives you a diameter of 1nm. This sort of calculation is important in mountain flying.
An accurate rate one turn is an important part of instrument flying.
Readability scale The readability scale (for radio transmissions) is:
1. Unreadable
2. Readable now and then
3. Readable but with difficulty
4. Readable
5. Perfectly readable
ROARS After engine start:
RPM - set to 1000
Oil - temperature and pressure in the green (within 20 seconds)
Amps - positive, indicating the alternator is working
Radio - on, switched to ATIS - listen to weather, check runway in use and set QNH on the altimeter
Strobes on.

Before engine shutdown:
RPM - 1000
Oil - pressure and temperature in the green
Amps - slightly positive
Radio - off
Switches - check magnetos - left off and on; look for the rpm drop, then right. Finally turn all switches off and pull mixture to full lean to shutdown
First encountered in lesson 5.
RoDRate of Descent, measured in feet per minute.
RPMRevolutions Per Minute. Engine speed. For example the Citabria should be taxiied at 1000 RPM (or the plugs are liable to oil up) and normal cruise is 2200 RPM.
SAND Effect of acceleration and deceleration on a magnetic compass:
In other words, when you accelerate, the compass will swing towards the south, and when you decelerate, it will swing towards the north. Not sure if this is the same in the northern hemisphere.
Demonstrated during lesson 31 - Basic Instrument Flight 1. See also: ONUS.
S&LStraight & Level.
SMCSurface Movement Control. Colloquially, 'Ground'. At Camden the Ground frequency is 121.9MHz, but in practice it is not used. When the Tower is operating, your first contact is with the tower at the hold point, and when the tower is not operating, you make a taxiing call on the CTAF frequency (120.1, same as the Tower).
Special VFR By day, when VMC does not exist, ATC may issue, at pilot request, a Special VFR clearance for flight in the Control Zone, or in a controlled area adjacent to the zone, for the purpose of entering or leaving the zone, provided:
  • the Special VFR flight will not unduly delay an IFR flight;
  • the flight can be conducted clear of cloud;
  • visibility is not less than 3000m;
  • the flight can be conducted in accordance with the requirements of CAR 157 with regards to low flying.
See lesson 68.
SPLStudent Pilot Licence. You can start training without this licence, but you need it to fly solo.
TAFTerminal Area Forecast. The most detailed weather forecast avaialble, produced for individual aerodromes worldwide. See example in lesson 6.
TBOTime Between Overhauls. Usually of engines.
TCASTraffic Collision Avoidance System. A black box on larger aircraft which detects transponder codes of nearby aircraft and warns of potential collisions.
TIFTrial Instructional Flight. An introductory lesson during which you decide whether flying's for you, and your instructor gets a feel for your aptitude and suitability.
TOSSTake Off Safety Speed. The speed you want to reach after take-off before you commence the climb. For the Citabria it's 52 knots.
VAManoeuvring speed (no full control deflections above this speed or you run the risk of structural damage).
VFRVisual Flight Rules. Flying and navigating using the Mk I eyeball. The only way I'll be flying unless I win Lotto.
VFEMaximum speed with flap extended.
VHFVery High Frequency. The 30-300MHz radio band used for most air to air and air to ground conversations, at least in populated areas. Other radio bands include HF.
VMC Visual Meteorological Conditions. Weather conditions suitable for flight by VFR.
Class D controlled airspace: Visibility 5000m; 1500m horizontal and 1000ft vertical distance from cloud. ATC may permit operations in weather conditions that do not meet these criteria (Special VFR)
Class G non-controlled airspace: At or below 3000ft AMSL or 1000ft AGL, whichever is higher: visibility 5000m; clear of cloud and in sight of ground or water.
Below 10,000ft AMSL: visibility 5000m; 1500m horizontal and 1000ft vertical distance from cloud.
Above 10,000ft AMSL: visibility 8000m; 1500m horizontal and 1000ft vertical distance from cloud.
VNENever exceed speed (or you run the risk of structural damage).
VNONormal operating speed.
VORVHF Omnidirectional Range. Ground equipment transmitting a coded signal at each bearing from 1° to 360°, and the aircraft-mounted receiver. An aircraft fitted with VOR can determine which radial (ie bearing) it is on with respect to the ground station, how much it is off track and whether the bearing is from or to the ground station.
VS0Stall speed in landing configuration (full flap).
VS1Stall speed in clean configuration (no flap) at MAUW.
VSI Vertical Speed Indicator in Citabria VH-RRW Vertical Speed Indicator. Shows rate of climb or descent in hundreds of feet per minute. The source is static pressure. Vertical Speed Indicator mechanism The Citabria's initial climb is well over 1000 feet/minute. The usual rate of descent is more gentle - 500 feet/minute. This is chosen as much for passenger comfort as for performance and handling reasons.
VTC Visual Terminal Chart. A large-scale chart covering the area around a major airport. Note that the yellow areas mark the shape of the lit areas at night. The area around The Oaks. Click to enlarge
VXSpeed for best angle of climb.
VYSpeed for best rate of climb (faster than VX because at a shallower angle).
WOSSSSSET Factors to evaluate when identifying a suitable emergency landing spot:
Wind (smoke, water, flags, ATIS)
Obstacles (power lines, fences, trees, high ground)
Size (at least 500m long. Width? )
Shape (try to find a straight runway shape)
Surface (hard and smooth. Look for ruts and holes. Ploughed (brown) is no good)
Slope (preferably land uphill. Use creeks and dams to get slope)
Sun (try not to land into a setting sun)
Elevation (to estimate high key/low key altitudes. Camden is 230'; The Oaks is 900')
Terrain (surrounding terrain may change the approach. Watch for wind shear)
Introduced in lesson 27 - Practice forced landings.

Other links:

  1. Australian Ultralight Federation Operations Manual
  2. The Alternative Aviation Glossary