Bahrain CAA CPL Theory Exam key terms

Visual Meteorological Conditions: weather in which visibility and distance from cloud meet the minimum values set for the airspace, allowing flight by visual reference to the ground and horizon.

Instrument Meteorological Conditions: weather below the visual minima for the airspace, requiring the flight to be conducted under instrument flight rules and by reference to instruments.

An authorisation allowing a flight to operate visually inside a control zone when the reported weather is below normal VMC minima, subject to ATC clearance and specified reduced visibility limits.

Controlled airspace extending upwards from the surface around an aerodrome, within which all flights require an ATC clearance and separation is provided for IFR traffic.

Airspace of defined dimensions in which air traffic control service is provided to all flights in accordance with airspace classification, and clearances are mandatory.

An authorisation issued by air traffic control for a flight to proceed under specified conditions; it does not relieve the pilot from responsibility for terrain clearance or safe operation.

The mandatory repetition by the pilot of safety-related ATC instructions such as route clearances, runway assignments and altimeter settings, confirming the message was correctly received.

The pressure value (QNH, QFE or standard 1013.25 hPa) set on the subscale so that the altimeter indicates the intended reference altitude or height.

The altitude at or below which the aircraft's altimeter is set to local QNH and above which it is set to standard pressure, separating terrain-referenced and flight-level-referenced operations.

A surface of constant atmospheric pressure referenced to standard pressure 1013.25 hPa and separated from other such surfaces by specified pressure intervals, expressed in hundreds of feet.

The altimeter subscale setting which, when applied at aerodrome elevation, causes the altimeter to indicate elevation above mean sea level.

The acute angle between the wing chord line and the relative airflow; lift increases with angle of attack until the critical angle where the airflow separates.

The angle of attack at which the wing produces maximum lift; exceeding it causes airflow separation and a stall regardless of airspeed, weight or attitude.

A condition in which the wing exceeds its critical angle of attack, causing loss of lift and often buffet or a sinking tendency, with recovery requiring reduction of the angle of attack.

The ratio of total lift produced to the aircraft's weight; it increases in turns and pull-ups, raising stall speed and structural stress on the airframe.

Never-exceed speed: the maximum speed at which the aircraft may be operated in any condition, marked by a red radial line on the airspeed indicator.

Maximum structural cruising speed: the top of the green arc, above which flight should be conducted only in smooth air and with caution.

Design manoeuvring speed: the maximum speed at which full and abrupt control deflection may be applied without exceeding the airframe's design load limits.

The point through which the total weight of the aircraft acts; its position within the permitted range affects stability, controllability, stall behaviour and performance.

The upward angle of the wings relative to the lateral axis; it provides lateral stability by generating a restoring rolling moment after a sideslip develops.

The tendency of an aircraft to yaw away from the direction of an applied aileron roll, caused by increased induced drag on the descending, higher-lift wing.

The initial tendency of an aircraft, after a disturbance from equilibrium, to return toward, remain at, or move further from its original flight condition.

Asymmetric thrust effect in a propeller aircraft at high angle of attack, where the descending blade takes a greater bite of air, producing a yawing moment toward the ascending blade side.

Abnormally rapid, explosive combustion of the fuel-air mixture in a reciprocating engine cylinder, causing high pressures, overheating and possible engine damage.

Ignition of the fuel-air mixture before the spark occurs, usually caused by a hot spot such as a glowing spark plug electrode or carbon deposit, leading to rough running and overheating.

Reduction of fuel flow in the fuel-air mixture to suit decreasing air density with altitude, improving economy and combustion while avoiding excessive cylinder temperatures.

Ice formation in the carburettor venturi and throttle area caused by fuel vaporisation and pressure drop, most likely at temperatures between about -10 and +20 degrees Celsius with high humidity.

The aircraft's pressure sensing system: the pitot tube supplies total pressure and static ports supply ambient pressure, together driving the airspeed indicator, altimeter and vertical speed indicator.

Obstruction of the pitot head, typically by ice or insects, causing unreliable airspeed indications; with the drain blocked, the indicator behaves like an altimeter as height changes.

A deficiency of oxygen reaching body tissues, causing impaired judgement, euphoria and loss of consciousness at altitude, with symptoms easily unnoticed by the affected pilot.

Abnormally rapid or deep breathing that reduces blood carbon dioxide, producing dizziness, tingling and confusion whose signs resemble those of hypoxia.

The period after exposure to a given altitude during which a pilot can still perform useful, conscious actions before incapacitation from oxygen deprivation.

A pilot's incorrect perception of aircraft attitude or motion relative to the earth, often arising from vestibular illusions in the absence of reliable visual references.

A false sensation of pitch caused by linear acceleration or deceleration, which may lead a pilot to perceive a climb during acceleration or a dive during deceleration.

International Standard Atmosphere: a reference model with sea-level temperature 15 degrees Celsius, pressure 1013.25 hPa, and a lapse rate of about 2 degrees Celsius per 1000 feet.

Pressure altitude corrected for non-standard temperature; high density altitude reduces engine power, propeller thrust and wing lift, lengthening take-off and reducing climb performance.

A sudden change of wind speed or direction over a short distance, including microbursts and frontal or low-level shear, capable of causing severe airspeed loss close to the ground.

A small, intense downdraught producing a damaging outflow at the surface; an aircraft first meets headwind, then downdraught, then tailwind, causing performance loss.

The leading edge of advancing cold air that undercuts warm air, producing rapid lifting, cumuliform cloud, showers, turbulence and a marked wind shift with pressure rise.

A circle on the earth's surface whose plane passes through the earth's centre; the shorter arc between two points gives the shortest surface distance between them.

A line crossing every meridian at the same angle; it appears straight on a Mercator chart but is longer than the great circle between the same two points.

The angular difference at a given place between true north and magnetic north, applied when converting between true and magnetic directions on charts and instruments.

Non-Directional Beacon: a ground station transmitting continuously in the low or medium frequency band, allowing an aircraft's automatic direction finder to display a bearing to the station.

VHF Omnidirectional Range: a ground beacon providing magnetic radial information to equipped aircraft, used for navigation, position fixing and airway tracking.

Global Navigation Satellite System: satellite-based positioning providing aircraft position, track and time, supporting area navigation, approach procedures and required navigation performance operations.

Required Navigation Performance: a specification of the navigation accuracy the aircraft must achieve on a route or procedure, with on-board performance monitoring and alerting.