CAAP PPL Knowledge Exam key terms

A document confirming that an individual aircraft meets its certified type design and is safe to operate. In the Philippines it is issued or validated under PCAR rules and must remain valid for flight to be legal.

The document recording the aircraft's registered owner and nationality mark. It identifies the aircraft legally, whereas the certificate of airworthiness identifies its fitness to fly; both must normally be carried on board.

A mandatory instruction issued by the state of design or manufacture requiring inspection, modification or limitation on an aircraft type. Compliance is compulsory and normally becomes a condition of continued validity of the certificate of airworthiness.

The letters and hyphenated symbols painted on an aircraft showing its state of registry and unique registration. Philippine-registered aircraft carry the prefix RP, followed by a hyphen and a letter-and-three-letter group.

The set of rules allowing flight by visual reference to the ground, subject to minimum flight visibility and distance from cloud. VFR also requires the pilot to remain clear of cloud and to see and avoid other traffic.

The weather minima of visibility and cloud distance in which flight under visual flight rules is permitted. When conditions fall below these minima the flight becomes instrument meteorological conditions and VFR flight is no longer lawful.

An authorisation allowing a VFR flight inside controlled airspace when weather is below normal VMC minima, subject to air traffic control clearance and specified visibility and cloud-clearance limits. It is normally requested by the pilot and granted at the controller's discretion.

Airspace of defined dimensions within which air traffic control service is provided to all flights in accordance with airspace classification. Pilots need a clearance to enter, and separation is provided according to the class of airspace concerned.

An authorisation for an aircraft to proceed under conditions specified by an air traffic control unit. It does not relieve the pilot in command of responsibility for safety, terrain clearance or avoidance of other aircraft.

The pilot responsible for the operation and safety of the aircraft during flight time. The PIC has final authority over the aircraft and may deviate from rules to the extent necessary in an emergency.

The acute angle between the wing chord line and the relative airflow. Increasing it raises lift up to the critical angle, beyond which the airflow separates and the wing stalls regardless of airspeed or attitude.

The angle of attack at which the wing reaches maximum lift coefficient and any further increase causes a stall. It is a fixed value for a given wing and can be reached at any speed, weight or attitude.

A loss of lift caused by airflow separation when the wing exceeds its critical angle of attack. Recovery requires reducing the angle of attack, typically by easing forward pressure, before applying power or levelling the wings.

Drag created as a by-product of lift, caused by the pressure difference between the upper and lower wing surfaces producing wingtip vortices. It is greatest at low speed and high angle of attack and decreases as speed increases.

The ratio of the total lift produced by an aircraft to its actual weight, expressed in g units. Manoeuvring or turbulence raises load factor, which increases stall speed and structural stress.

The point at which the aircraft's total weight is considered to act. Its position must remain within the certified forward and aft limits, since it affects stability, control effectiveness and stall recovery.

The weight of a standard aircraft including structure, powerplant, fixed equipment, unusable fuel and full operating fluids. It forms the starting point for mass and balance calculations before crew, payload and usable fuel are added.

The highest mass approved for the start of the take-off run, covering aircraft, crew, payload and fuel. Exceeding it degrades climb performance, increases take-off distance and may overstress the structure.

Pressure altitude corrected for non-standard temperature, representing the altitude the aircraft's performance feels. High temperature or low pressure raises density altitude and lengthens take-off and landing distances while reducing climb rate.

The altitude indicated on an altimeter set to the standard datum of 1013.25 hPa or 29.92 inHg. It is used in performance charts and as the basis for flight levels above the transition altitude.

The pressure value dialled into the altimeter subscale so the instrument reads height above a chosen datum. Pilots use QNH for local elevation, QFE for height above a reference point, and standard pressure for flight levels.

The altitude above which pilots set the altimeter to standard pressure and report flight levels instead of altitudes. Below the transition level, local QNH is used so that terrain clearance is referenced to mean sea level.

A condition in which body tissues receive insufficient oxygen, causing impaired judgement, euphoria and loss of consciousness. It can occur from altitude exposure, restricted breathing or carbon monoxide contamination, and is insidious because the pilot may not notice it.

Excessive breathing rate or depth that lowers blood carbon dioxide, producing dizziness, tingling and faintness. Symptoms resemble hypoxia, so treatment is to slow the breathing rate and, if doubt remains, treat as hypoxia with oxygen.

A pilot's mistaken perception of aircraft attitude or motion, usually when visual references are lost. It arises from vestibular illusions such as the leans or somatogravic effect and is countered by trusting flight instruments and avoiding sudden head movements.

False sensations of motion generated by the inner ear when the head accelerates or rotates. Common forms include the leans, the graveyard spiral and the somatogravic illusion during rapid acceleration or deceleration.

The period after loss of oxygen supply during which a person can still take corrective action before becoming incapacitated. It shortens rapidly with altitude, falling to roughly 15 to 20 seconds near 40,000 feet.

The altimeter subscale setting that makes the instrument read elevation above mean sea level when the aircraft is on the ground. It is the normal setting for take-off, landing and flight below the transition altitude.

A line on a weather chart joining places of equal mean sea level pressure. Closely spaced isobars indicate a steep pressure gradient and therefore stronger surface winds.

The rate of pressure change over horizontal distance, shown by isobar spacing. A steep gradient produces strong winds, modified in direction and speed by Coriolis force and surface friction.

A daytime coastal wind blowing from sea to land as the land heats faster than the water. It typically develops in the afternoon, can reach 15 to 20 knots and may create a shallow convergence zone inland.

Cloud formed when moist air is forced to rise over hills or mountains and cools to its dew point. It often appears as lenticular or cap cloud and signals updraughts, turbulence and possible mountain-wave activity.

The temperature to which air must be cooled at constant pressure for it to become saturated. A small gap between temperature and dew point indicates high relative humidity and a likelihood of fog or low cloud.

The speed of the aircraft through the air mass, corrected for position error, instrument error, compressibility and air density. It is used for navigation calculations and increases above indicated airspeed as altitude rises.

The speed shown on the airspeed indicator, uncorrected for installation and density errors. It is the value used against aircraft limitation and performance speeds because it reflects dynamic pressure and thus lift and structural loading.

The direction in which the aircraft's longitudinal axis points, measured clockwise from a reference such as true or magnetic north. Heading differs from track by the drift caused by wind.

The actual path of the aircraft over the ground, expressed as a direction from a reference north. It results from the combination of heading and wind, and is the line drawn on a navigation chart.

The angular difference at a given place between true north and magnetic north. It is shown on charts as east or west variation and must be applied to convert between true and magnetic directions.

The error of a magnetic compass caused by the aircraft's own magnetic fields and electrical equipment. It varies with heading and is recorded on a compass deviation card that the pilot applies to obtain compass heading.

The procedure by which a pilot repeats back safety-related parts of an air traffic control clearance to confirm correct reception. Items such as route, altitude, heading and frequency must be read back in full.

The standard ICAO spelling alphabet used to pronounce letters unambiguously in radiotelephony, such as Alfa, Bravo and Charlie. It is used for registration letters, waypoint identifiers and unclear words.

The four-digit code set in the aircraft transponder to identify it to secondary surveillance radar. Codes are assigned by air traffic control, with 7700 for emergency, 7600 for radio failure and 7500 for unlawful interference.

An airborne radar beacon transmitter that replies to interrogations from ground radar with identity and altitude information. It improves identification and separation and is mandatory in much controlled airspace.

A ground-based navigation aid transmitting radial information so that aircraft can determine their bearing from the station. A VOR receiver with a course deviation indicator allows tracking of selected radials and position fixing.

A magnetic bearing from a VOR station, measured in degrees clockwise from magnetic north. A pilot flying towards a station tracks the reciprocal of the radial being received.

A radio aid that measures slant range from the aircraft to a ground station by timing signal exchanges. The reading is slightly greater than ground distance and is most accurate directly overhead.

A satellite-based system providing position, velocity and time worldwide, used for en-route navigation and instrument approaches. Receiver autonomous integrity monitoring warns the pilot when position accuracy is unreliable.