JCAA ATPL Theory key terms

The lowest flight visibility a VFR flight may have while inside controlled airspace; in Japan this is generally 8 km at and above 3,000 m AMSL and 5 km below, with stricter limits near aerodromes and in control zones.

A clearance letting a flight operate within a control zone in weather below normal VFR minima, subject to an ATC clearance and, in Japan, a specified ground visibility and ceiling; the pilot must remain clear of cloud and in sight of the surface.

Controlled airspace extending upward from the surface around an aerodrome, within which all flights need an ATC clearance; its lateral and vertical limits are published in the national AIP.

The published altitude above which a pilot sets the standard pressure reference and reports flight levels instead of altitudes; it is fixed for a given area and shown on approach and aerodrome charts.

A surface of constant atmospheric pressure referenced to a standard pressure datum, expressed in hundreds of feet, used above the transition altitude so that all aircraft share the same pressure reference.

The pressure value set on the subscale so that the altimeter reads elevation above mean sea level when on the ground; it is the normal setting for takeoff, approach and landing.

A mandatory instruction issued by the state of design and adopted by the authority of registry, requiring inspection, modification or limitation on an aircraft or component to correct an unsafe condition.

An approved document, derived from the master minimum equipment list, that specifies which instruments and equipment may be inoperative for dispatch under stated conditions and any operational limitations that then apply.

The document confirming that an individual aircraft conforms to its approved type design and is in a condition for safe operation, subject to continuing maintenance and validity requirements set by the state of registry.

A propeller whose blade angle is automatically varied by a governor to hold a selected engine speed, converting engine power into thrust efficiently across changing airspeed and load conditions.

The absolute pressure of the air-fuel mixture in the engine intake, displayed on a gauge and used with engine speed to set power in a piston engine with a constant-speed propeller.

The range of permissible center-of-gravity positions, forward and aft limits, within which the aircraft may be operated; exceeding it degrades stability or control authority and may invalidate performance data.

The mass of the aircraft with structure, powerplant, systems, unusable fuel and full operating fluids, excluding crew, payload and usable fuel; it is the starting figure for mass and balance computation.

The final document showing the distribution of traffic load, the computed mass and center of gravity, and confirmation that the aircraft is within limits before departure, signed by the responsible person.

The shortest runway length for which the accelerate-stop distance and the accelerate-go distance are equal, so that a decision speed exists allowing either a safe stop or a continued takeoff.

The length of the takeoff run available plus any clearway, defining the maximum horizontal distance declared for a takeoff; it bounds the distance to reach a defined height over the end of the runway.

The decision speed at which, following an engine failure, the pilot can either stop within the remaining runway or continue the takeoff and meet the required screen height; it is set before takeoff.

A condition in which the tissues receive insufficient oxygen, causing impaired judgment, euphoria and loss of consciousness; it may be hypoxic, anaemic, stagnant or histotoxic in origin.

The period after loss of oxygen supply during which a person can still take effective corrective action before becoming incapacitated; it shortens rapidly as cabin altitude increases.

Abnormally rapid or deep breathing that lowers blood carbon dioxide, producing dizziness, tingling and cramps that can resemble hypoxia; treatment is to slow the breathing rate.

A false perception of the aircraft's position or motion, usually arising when visual references are lost and the pilot misinterprets vestibular or somatosensory cues; recovery relies on trusting flight instruments.

A false sensation of pitching up or down caused by linear acceleration or deceleration, which can lead a pilot to push or pull incorrectly during takeoff or go-around in poor visual conditions.

A defined reference atmosphere with sea-level temperature of 15 C, pressure 1013.25 hPa and a fixed lapse rate, used to compare and compute aircraft performance independent of actual conditions.

The pressure altitude corrected for non-standard temperature; high density altitude reduces engine power, propeller or jet thrust and lift, lengthening takeoff runs and reducing climb performance.

The altimeter subscale setting that makes the instrument indicate elevation above mean sea level at the aerodrome; it is the standard setting for departure, approach and landing.

A change in wind speed or direction over a short distance, often associated with fronts, thunderstorms or inversions, that can cause sudden airspeed and lift changes close to the ground.

A localized downdraft producing a divergent outflow at the surface, typically under a thunderstorm, that causes a headwind then tailwind change and severe performance loss on approach or departure.

An automated aerodrome warning service using surface and remote sensors to detect wind shear below a stated height and transmit alerts to pilots and controllers.

The shortest path between two points on the surface of a sphere, formed by the intersection of the surface with a plane through the centre; its track direction changes continuously along the route.

A path crossing all meridians at the same angle, appearing as a straight line on a Mercator chart; it is longer than the great circle except along a meridian or the equator.

The magnetic bearing from a VOR station to the aircraft's position, displayed by the course deviation indicator; tracking a radial inbound or outbound gives a defined line of position.

A radio system that measures slant range to a ground transponder by timing signal round trips, giving continuous distance information that combines with a VOR radial for a position fix.

A discontinued approach followed by a climb to a safe altitude and a new approach or diversion; the pilot must apply power, follow the published missed-approach procedure and notify ATC.

A published sequence of turns and climbs to be flown if the approach cannot be completed, designed to keep the aircraft clear of obstacles while it climbs to a holding fix or diversion point.

The angle between the wing chord line and the relative airflow; lift increases with it up to the critical angle, beyond which the airflow separates and the wing stalls.

The angle at which the wing produces maximum lift; any further increase causes separation and stall regardless of airspeed, weight or bank angle.

The ratio of total lift to weight, expressed in g; it increases in turns and manoeuvres and raises the stall speed, since the wing must support more than the aircraft's weight.

A mandatory repetition by the pilot of safety-related clearances and instructions, such as route, level, heading, speed and frequency, so the controller can verify correct receipt.

The prescribed words and sentence patterns used in radiotelephony to convey clearances and reports unambiguously; plain language is used only when no standard phrase fits.

The four-digit octal code selected on the transponder to identify the aircraft on secondary surveillance radar as assigned by ATC, with defined codes reserved for emergencies and radio failure.