GCAA CPL Theory Exam (GCAA) flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Class G airspace

Uncontrolled airspace where ATC provides no separation service to IFR or VFR aircraft; pilots are responsible for collision avoidance and must comply with VMC or IMC rules as applicable.

Semicircular rule

ICAO rule assigning odd flight levels for magnetic tracks 000–179° and even flight levels for 180–359°, reducing head-on conflict risk between aircraft cruising in opposite directions.

VFR cloud clearance above 900 m

In Class C–E airspace above 900 m AMSL, VFR requires 8 km visibility, 1500 m horizontal distance and 300 m vertical distance from cloud.

Certificate of airworthiness

Document confirming the aircraft meets the applicable airworthiness requirements and is maintained in a condition safe for flight; must be carried on board.

Four-stroke engine cycle

Intake, compression, power and exhaust strokes; the crankshaft rotates twice per complete cycle, producing one power stroke per cylinder.

Detonation

Uncontrolled explosive combustion of the fuel-air mixture in the cylinder caused by excessive pressure and temperature; produces knocking, power loss and possible engine damage.

Carburettor icing risk

Highest between about −7 °C and +21 °C with high humidity; ice forms in the venturi from fuel vaporisation cooling and can cause rough running or engine stoppage.

Constant-speed propeller governor

Device regulating oil pressure to adjust blade angle; increasing pitch reduces RPM, decreasing pitch increases RPM, maintaining selected engine speed.

Density altitude formula

Density altitude equals pressure altitude plus 120 times the difference between actual temperature and ISA temperature at that level, in degrees Celsius.

Crosswind component

Wind speed multiplied by the sine of the angle between wind direction and runway heading; used to verify the crosswind limit in the aircraft flight manual.

Centre of gravity calculation

Total moment divided by total weight, where each moment is weight multiplied by arm; the result must lie within the forward and aft CG limits.

Final reserve fuel

Fuel required to hold for 30 minutes at 1500 ft above the alternate for turbine aircraft, or 45 minutes for piston aircraft, under ICAO Annex 6.

Time of useful consciousness

Period before hypoxia impairs function; about 30–60 seconds at FL 350 and 3–5 minutes at FL 250 without supplemental oxygen.

Somatogravic illusion

False sensation of climbing or descending during rapid acceleration or deceleration; pilots should rely on instruments rather than bodily sensations.

Rods and night vision

Rod cells in the peripheral retina provide low-light vision, require about 30 minutes dark adaptation, and are insensitive to colour and fine detail.

Circadian low periods

Times of lowest alertness, roughly 02:00–06:00 and 14:00–16:00 local time, when fatigue-related errors and microsleeps are most likely.

QNH and QFE

QNH is pressure reduced to sea level for altimeter setting; QFE is pressure at the aerodrome reference point, giving height above the aerodrome.

Clear ice

Dense, transparent ice formed by large supercooled droplets freezing slowly on impact; most hazardous and often associated with freezing rain.

Microburst

Small-scale downdraft producing a sudden outflow; can exceed 6000 ft/min descent and cause severe low-altitude wind shear; avoid by at least 20 NM.

CAVOK

Meteorological code meaning visibility 10 km or more, no cloud below 5000 ft or the minimum sector altitude, and no significant weather phenomena.

Great circle

Shortest path between two points on a sphere; its direction changes continuously and it appears curved on a Mercator chart.

VOR radial

Magnetic bearing from the VOR station; the CDI centres when the selected OBS matches the radial, and the TO/FROM flag indicates direction relative to the station.

Magnetic variation east

When variation is east, subtract it from true to obtain magnetic; add it when converting magnetic to true (east is least, west is best).

RAIM

Receiver autonomous integrity monitoring detects satellite faults by comparing redundant signals; required for GPS-based IFR approaches and predicted before flight.

Aviate, navigate, communicate

Priority order in an emergency: first maintain control of the aircraft, then determine position and route, then communicate with ATC.

Engine failure after take-off

Maintain control, pitch for best glide or VY, select a landing site, attempt restart per checklist, and transmit MAYDAY if unable to restart.

Emergency descent procedure

Don oxygen masks, descend to 10 000 ft or MSA, notify ATC, and shut off pressurisation outflow valve to accelerate descent if applicable.

Volcanic ash encounter

Avoid ash clouds; if encountered, reduce thrust, turn 180°, and report to ATC; ash damages engines, pitot-static system and airframe.

Lift equation

Lift equals half the air density multiplied by velocity squared, wing area and lift coefficient; it increases with density, speed squared and angle of attack.

Stall at critical angle

Stall occurs when the angle of attack exceeds the critical value, regardless of speed, weight or attitude; recovery requires reducing angle of attack.

Load factor and stall speed

Load factor is lift divided by weight; stall speed increases with the square root of load factor, so at 60° bank it rises by about 41 percent.

MAYDAY and PAN PAN

MAYDAY is the distress signal repeated three times for grave and imminent danger; PAN PAN is the urgency signal for urgent but non-distress situations.