Mauritius DCA CPL Theory key terms

A document confirming that an aircraft meets its type design and is safe to fly. It must remain valid for flight, and the aircraft must be maintained under an approved programme for it to stay in force.

The document that records the aircraft's nationality and registration marks and identifies its legal owner. It must be carried on board and matches the marks painted on the aircraft.

A mandatory instruction issued by the state of design or registry requiring inspection, modification or limitation of an aircraft or component. Compliance is compulsory and normally must be recorded in the aircraft logbooks.

Rules allowing flight where the pilot sees and avoids other traffic and obstacles, subject to minimum visibility and distance-from-cloud criteria. VFR also requires cloud ceiling and ground visibility at or above the specified minima.

Rules under which the flight is conducted mainly by reference to instruments, with separation from other IFR traffic provided by air traffic control. The pilot must hold an instrument rating and the aircraft must be suitably equipped.

A clearance allowing a flight to operate in controlled airspace below VFR meteorological minima, provided the pilot remains clear of cloud and in sight of the surface. It is normally available only within a control zone.

Controlled airspace extending from the surface upwards around an aerodrome, within which all flights require an ATC clearance. It protects arriving and departing traffic and often contains the aerodrome traffic circuit.

Controlled airspace above a specified lower limit, usually 200 feet above the surface, within which IFR flights receive separation. VFR flights may enter only under the conditions and clearances specified for that airspace class.

A lettered system (A to G) defining the services, separation and clearances provided in each type of airspace. Classes differ mainly in whether IFR and VFR flights are permitted and whether separation is provided.

A four-digit octal code selected in the aircraft's transponder, broadcast in reply to secondary radar interrogations. ATC assigns discrete codes; 7700, 7600 and 7500 denote emergency, radio failure and unlawful interference respectively.

The angular difference between the wing chord line and the horizontal tailplane chord line when the aircraft is rigged. It determines the angle of attack the aircraft tends to hold at a given power setting.

The fixed angle between the wing chord line and the longitudinal axis of the aircraft, set by the manufacturer. It differs from the angle of attack, which changes in flight as the relative airflow direction alters.

A certification, made after maintenance, that the work has been completed and the aircraft or component is serviceable. It is signed by an appropriately authorised person and must be entered in the technical log.

The aircraft's operational record containing details of defects, rectification, maintenance releases and flight times. It travels with the aircraft and must be available to the pilot before flight.

An approved document listing items of equipment that may be inoperative while the aircraft is dispatched, subject to specified conditions and limitations. It must not be less restrictive than the master minimum equipment list.

The point at which the aircraft's weight is considered to act. Its position must remain within the certified forward and aft limits for safe control and performance, and it changes with loading and fuel burn.

The calculation of total aircraft mass and the position of the centre of gravity, using the basic empty mass, crew, fuel, payload and baggage. Results must fall inside the certified mass and CG envelope.

The mass of the aircraft including its structure, powerplant, required equipment, unusable fuel and full operating fluids, but excluding crew, usable fuel and payload. It is the starting figure for any mass and balance calculation.

The maximum certified mass at which the aircraft may begin the take-off run. It is a structural and performance limit that must be respected regardless of available runway length or weather conditions.

The horizontal distance from crossing the runway threshold at a specified height to the aircraft coming to a complete stop. It is normally multiplied by a safety factor to give the required landing distance.

The distance required from brake release to reaching a specified height above the runway, allowing for rotation and initial climb. It increases with mass, altitude, temperature and unfavourable wind.

The altitude at which the aircraft would perform as if the air were at standard density, derived from pressure altitude and temperature. High density altitude reduces engine power and lift, lengthening take-off runs.

A condition in which body tissues receive insufficient oxygen, causing impaired judgement, euphoria and eventually unconsciousness. It becomes significant above about 10,000 feet and is insidious because the affected pilot may not notice it.

The period after loss of oxygen supply during which a person can still perform useful tasks before becoming incapacitated. It shortens rapidly with increasing altitude and is reduced by cold, fatigue and exertion.

A false perception of the aircraft's position or motion, usually caused by conflicting vestibular and visual cues in the absence of a reliable horizon. Recovery depends on trusting and interpreting the flight instruments.

False sensations of rotation or tilt arising from the inner ear's semicircular canals and otolith organs, especially during prolonged turns or acceleration. They are a common cause of disorientation in instrument conditions.

A false sensation of pitching up during acceleration or pitching down during deceleration, caused by otolith stimulation. In flight it can lead to inappropriate control inputs, particularly after take-off or in go-around situations.

Excessive breathing rate or depth that lowers blood carbon dioxide, producing dizziness, tingling and a feeling of suffocation. Symptoms resemble hypoxia, so treatment begins with controlled breathing and the use of supplemental oxygen.

A layer of air in which temperature increases with height, reversing the normal lapse rate. It stabilises the atmosphere, traps moisture and pollutants beneath it, and is often associated with fog and poor visibility.

The rate at which air temperature decreases with increasing height. The standard atmosphere assumes 2 degrees Celsius per 1,000 feet, while the saturated adiabatic rate is smaller than the dry adiabatic rate.

Cloud at ground level, formed when air is cooled to its dew point or moisture is added. It reduces visibility below the VFR minima and is classified as radiation, advection, frontal or upslope depending on its formation.

The temperature to which air must be cooled, at constant pressure, for it to become saturated. A small difference between temperature and dew point indicates a high likelihood of cloud, fog or carburettor icing.

Ice build-up inside a carburettor caused by the cooling effect of fuel vaporisation and pressure reduction. It can occur at outside temperatures well above freezing and causes a gradual loss of engine power.

The speed of the aircraft through the air mass, corrected for position error and for the change of air density with altitude. It is used in navigation calculations and increases with altitude for a given indicated speed.

The speed of the aircraft relative to the ground, obtained by combining true airspeed with the wind vector. It determines time en route and fuel consumption over the ground.

A vector diagram combining true heading and true airspeed with the wind velocity to find track and groundspeed. It is the basis for calculating heading and drift on a navigation flight plan.

The path of the aircraft over the ground, measured in degrees from true or magnetic north. The difference between track and heading is the drift angle caused by wind.

The angle between the wing chord line and the relative airflow. Lift increases with angle of attack up to the critical angle, beyond which the wing stalls.

A condition in which the wing exceeds its critical angle of attack and lift decreases sharply. It can occur at any speed or attitude, and recovery requires reducing the angle of attack.

The ratio of the lift produced by the aircraft to its weight, expressed in g. Increased load factor in turns raises the stall speed and the structural loads on the airframe.

A radar system that interrogates aircraft transponders and receives coded replies, providing identity and altitude information. It enables ATC to identify and separate traffic in controlled airspace.

A radio aid that measures the slant range from the aircraft to a ground station by timing signal exchanges. The reading is slightly greater than the horizontal distance because of aircraft height.

A ground-based navigation beacon that transmits radio signals allowing the aircraft to determine its magnetic bearing from the station. It is used for tracking to or from the beacon and for position fixing.