Mauritius DCA IR Theory key terms

The set of rules governing flight in instrument meteorological conditions or in controlled airspace under an IFR clearance, requiring the pilot to follow prescribed procedures, separation and equipment standards.

An authorisation from air traffic control for an aircraft to proceed under instrument flight rules within controlled airspace, including route, altitude, and any restrictions or instructions.

The lowest altitude providing at least 1,000 feet of obstacle clearance within a 25 nautical mile radius of a navigation aid or waypoint, usually depicted on approach charts.

The lowest published altitude for an airway segment that ensures obstacle clearance and, where required, navigation signal coverage along the entire route.

A radio message to air traffic control stating the aircraft's identification, position, time, altitude, and next reporting point, used to maintain separation in non-radar airspace.

Weather conditions below the prescribed minima for visual flight, expressed in visibility and distance from cloud, requiring the flight to be conducted under instrument flight rules.

Weather conditions equal to or better than the prescribed visibility and cloud-distance minima, permitting flight under visual flight rules when other requirements are met.

A gyroscopic instrument displaying pitch and roll relative to the horizon, forming the primary reference for aircraft attitude during instrument flight.

A gyroscopic direction instrument showing magnetic or true heading, used as the primary heading reference because it is more stable and less prone to turning errors than a magnetic compass.

The system of pitot tube, static ports, and connecting lines that supplies total and static pressure to the airspeed indicator, altimeter, and vertical speed indicator.

A blockage of the pitot intake that traps pressure, causing the airspeed indicator to behave like an altimeter, over-reading in a climb and under-reading in a descent.

A secondary static pressure port selectable in flight when the main static source is blocked, restoring approximately correct altitude and airspeed indications at the cost of some error.

An engine-driven pump system that spins the gyroscopes of attitude and heading indicators; loss of suction causes unreliable or failing gyroscopic indications.

The pressure value set on the altimeter subscale so that the instrument indicates altitude above a chosen reference, such as mean sea level or a standard pressure level.

The altitude at or below which the altimeter is set to the local pressure setting and above which the standard setting of 1013.2 hPa is used.

The lowest flight level available for use above the transition altitude, ensuring at least the prescribed vertical separation from aircraft operating at the transition altitude.

A surface of constant atmospheric pressure related to the standard pressure datum of 1013.2 hPa, expressed in hundreds of feet and separated by prescribed intervals.

The altitude indicated when the altimeter is set to the standard pressure datum, used for aircraft performance calculations and flight level assignment.

Pressure altitude corrected for non-standard temperature, representing the altitude at which the aircraft would perform; high values reduce engine power, lift, and climb performance.

The horizontal distance required from the start of the take-off run to the point where the aircraft reaches a defined height, affected by mass, altitude, temperature, and wind.

The horizontal distance required from crossing the threshold at a specified height to a full stop, adjusted for wind, slope, surface condition, and mass.

A runway whose surface is covered by standing water, slush, snow, or ice in excess of defined depths, reducing braking action and increasing landing distance.

Loss of tyre contact with the runway because a film of water supports the tyre, sharply reducing braking and directional control at higher speeds.

The calculation of fuel required for taxi, trip, contingency, alternate, final reserve, and any extra fuel, ensuring legal reserves remain on arrival.

The minimum fuel that must remain on landing, normally expressed as fuel for a defined holding period at a specified altitude, protecting against unforeseen delays.

An aerodrome to which a flight may proceed if approach or landing at the destination is not possible, requiring suitable weather and sufficient fuel.

A pilot's incorrect perception of aircraft attitude or motion relative to the earth, typically arising when visual references are lost and misleading vestibular or somatosensory cues dominate.

The inner-ear organs, including semicircular canals and otoliths, that sense rotation and linear acceleration but cannot distinguish gravity from sustained acceleration.

A false sensation of pitch caused by linear acceleration or deceleration, making a pilot believe the aircraft is climbing during acceleration or descending during deceleration.

An error of the magnetic compass during turns in the northern or southern hemisphere, causing it to lead or lag the actual heading depending on the direction of turn.

The angular difference between true north and magnetic north at a given location, applied when converting between true and magnetic directions.

A navigation method that calculates present position from a known starting point using heading, airspeed, elapsed time, and wind estimates.

The speed of the aircraft relative to the ground, obtained by combining true airspeed with the wind vector, and used to calculate times and fuel.

A vector diagram relating true airspeed, wind velocity, and groundspeed with drift, used to compute heading and time for a planned track.

A magnetic bearing from a VOR station, identified by the course selector and CDI, along which an aircraft can determine its position relative to the station.

A radio aid that measures slant range from the aircraft to the ground transponder, providing distance readout used with VOR or ILS for position fixing.

A navigation method allowing aircraft to fly on any desired path within the coverage of navigation aids or satellite systems, rather than directly to or from stations.

A navigation specification stating the on-board performance monitoring and alerting required to operate within a defined lateral accuracy value along a route.

A published series of manoeuvres from an initial fix to a landing or missed approach, designed to provide obstacle clearance and safe descent in instrument conditions.

A specified altitude in a precision or approach-with-vertical-guidance procedure at which a missed approach must be initiated if the required visual reference is not established.

The lowest altitude to which descent is authorised on a non-precision approach, below which the aircraft must not descend unless the required visual reference is in sight.

The published manoeuvre flown when an approach cannot be completed, following a defined climb path and routing to a holding fix or alternate clearance.

A racetrack manoeuvre flown at a specified fix and altitude to absorb delay, with defined inbound leg, turns, timing, and wind correction.

A change in wind speed or direction over a short distance, often associated with fronts or thunderstorms, which can cause sudden airspeed and lift changes on approach.

A concentrated downdraft from a thunderstorm that spreads out at the surface, producing severe and rapidly reversing wind shear hazardous near the ground.

Accretion of ice on aircraft surfaces when flying through supercooled water droplets, degrading lift, increasing drag and weight, and affecting pitot and static sources.

The altitude at which the air temperature is zero degrees Celsius, marking the lower boundary of potential airframe icing in cloud.

The angle of attack at which the wing reaches maximum lift and beyond which the airflow separates, causing a stall regardless of airspeed or attitude.

A condition in which the wing exceeds its critical angle of attack, with loss of lift and characteristic buffet or warning, requiring reduction of angle of attack for recovery.

The ratio of total lift to aircraft weight; increasing in turns, it raises the stall speed and structural stress on the airframe.

The angle between the wing chord line and the relative airflow, determining lift production and the proximity to the stall.