ICAA PPL Theory cheat sheet

ICAO Annex 2 (Rules of the Air) applies to all aircraft; VFR minima, right-of-way rules and light signals derive from it and from the applicable national AIP.

Right-of-way: converging aircraft of the same category give way to the one on the right; power-driven give way to gliders, airships and balloons; all give way to aircraft landing or in final approach.

VMC minima below 3,050 m (10,000 ft) AMSL in Class C-E airspace: 5 km flight visibility, 1,500 m horizontally and 300 m (1,000 ft) vertically from cloud.

Class G VMC minima at or below 900 m AMSL: 5 km visibility, clear of cloud and in sight of the surface; above 900 m AMSL: 5 km, 1,500 m horizontally and 300 m vertically from cloud.

Squawk 7500 unlawful interference, 7600 radio failure, 7700 general emergency; these codes are set on the transponder and announced on the emergency frequency 121.5 MHz.

Aircraft must be operated with a valid certificate of airworthiness (or permit), certificate of registration, and crew licences carried or available as required by the State of Registry.

Anti-collision and navigation lights: navigation lights required between sunset and sunrise or in reduced visibility; anti-collision lights on whenever engines are running.

Pre-flight actions: file flight plan where required, obtain ATC clearance before entering controlled airspace, and confirm altimeter setting source (QNH/QFE) with the briefing.

Four-stroke cycle: induction, compression, combustion (power), exhaust; the camshaft turns at half crankshaft speed, so each cylinder fires once per two revolutions.

Mixture control: full rich for take-off and climb; lean for cruise above ~3,000 ft density altitude; lean further at high altitude to maintain EGT peak or best-power setting.

Carburettor icing risk is highest at ambient temperatures between -5 °C and +15 °C with high humidity; apply carburettor heat and expect a temporary RPM drop before recovery.

Magneto check: at run-up, select each magneto in turn; maximum allowable drop and differential are specified in the AFM (typically 150 RPM drop, 50 RPM differential).

Electrical system: alternator/generator charges the battery and supplies bus; ammeter shows charge/discharge; a failed alternator leaves battery-only endurance limited by load shedding.

Pitot-static: pitot tube supplies dynamic pressure to the airspeed indicator; static port supplies static pressure to ASI, altimeter and VSI; blockage of static causes ASI to read high in climb.

Fuel system: gravity feed or pump feed; check quantity, grade/colour and water/sediment drains during pre-flight; unusable fuel is stated in the AFM and excluded from range calculations.

Landing gear and brakes: toe brakes are independent left/right; differential braking assists directional control; check tyre condition, brake fluid and parking brake before taxi.

Density altitude = pressure altitude + 120 × (OAT − ISA temperature at that pressure altitude); high density altitude reduces both power output and lift.

Take-off and landing distances from the AFM/POH charts must be corrected for pressure altitude, temperature, weight, wind and runway slope/surface; add 15% for dry grass, more for wet.

Weight and balance: compute moments (weight × arm) and divide total moment by total weight to obtain CG position; the CG must lie within the forward and aft limits for all phases.

Crosswind component = wind speed × sin(angle between wind and runway); headwind component = wind speed × cos(angle); use the AFM maximum demonstrated crosswind.

Endurance = usable fuel ÷ fuel flow; range = endurance × TAS; always retain a final reserve (typically 30 minutes VFR by day, 45 minutes at night) per applicable rules.

Climb gradient (%) = (climb rate in ft/min ÷ ground speed in knots) × 100 / 1.013; required gradients for obstacle clearance are published on departure charts.

Altimeter errors: flying from high to low pressure without resetting reads higher than actual; flying from warm to cold air reads higher than actual (cold-temperature correction).

Flight plan fuel: taxi, trip, contingency, alternate and final reserve; note that unusable fuel and unaccounted fuel must be included in the planning figures.

Hypoxia: symptoms include euphoria, impaired judgement, headache and cyanosis; time of useful consciousness at 25,000 ft is roughly 3-5 minutes, at 35,000 ft roughly 30-60 seconds.

Hyperventilation produces dizziness, tingling and visual disturbance; treat by slowing the breathing rate; if hypoxia is suspected, use supplemental oxygen first.

Spatial disorientation: somatogravic illusion during acceleration feels like a climb; the leans occur after a gradual bank; trust the instruments, not sensations.

Night vision uses rods, which are slow to adapt (20-30 minutes) and are degraded by smoking, alcohol and bright light; use off-centre viewing to detect dim objects.

Cabin altitude above 10,000 ft requires supplemental oxygen for crew; above 12,500 ft for passengers after 30 minutes; above 14,000 ft continuously, per typical regulations.

Decompression sickness (DCS) risk rises with altitude exposure and repetitive diving; a common rule is no flying within 12-24 hours after diving, per the applicable guidance.

Fatigue and circadian rhythm: performance is lowest around 03:00-05:00 and 15:00-17:00 body time; sleep loss degrades vigilance and decision-making before subjective awareness.

Alcohol: even small amounts impair judgement and reaction time; common regulatory limit is 0.04% BAC (or 0.02% in some States), with a minimum 8-hour bottle-to-throttle rule.

ISA: sea-level temperature 15 °C, pressure 1013.25 hPa, lapse rate 1.98 °C per 1,000 ft (about 2 °C/1,000 ft) up to the tropopause (~36,090 ft).

QNH set on the subscale gives altitude above mean sea level; QFE gives height above the reference datum; QNE (1013.25) is used above the transition level.

Standard pressure lapse: 1 hPa ≈ 30 ft near sea level; the altimeter reads high when flying into lower pressure and low when flying into higher pressure.

Cloud base estimate: cloud base (ft) ≈ (temperature − dewpoint in °C) × 400; a small spread means high relative humidity and a low cloud base.

Stable air gives stratiform cloud, steady precipitation and smooth air; unstable air gives cumuliform cloud, showers, turbulence and good visibility between showers.

Fronts: at a warm front, warm air overruns cold air, giving a long period of lowering cloud and steady rain; at a cold front, steep uplift gives narrow bands of showers and squalls.

Icing: structural icing occurs roughly between 0 °C and -20 °C in visible moisture; clear ice forms in large supercooled droplets, rime ice in small droplets.

Wind: the surface wind backs (turns anticlockwise) in the Northern Hemisphere when the wind veers with height; a veering wind with height indicates warm advection.

Great circle: shortest path on the Earth's surface; rhumb line: constant track, easier to fly but longer except along the equator or a meridian.

1 minute of latitude = 1 nautical mile; 1 minute of longitude = 1 NM × cos(latitude); a degree of latitude is 60 NM.

Track is the intended path over the ground; heading is the direction the nose points; drift = track − heading; wind correction angle is applied opposite to drift.

True airspeed: TAS ≈ IAS × (1 + 0.02 × altitude in thousands of feet) for a rough estimate; use the navigation computer for accurate values.

1-in-60 rule: a 1° error over 60 NM produces a 1 NM offset; use it to compute closing angles and heading corrections.

Magnetic variation: east variation is subtracted from true to get magnetic (east is least); deviation is aircraft-specific and read from the compass correction card.

VOR: radial indicates the bearing from the station; CDI centred with TO/FROM flag gives the selected course; a reverse sensing error occurs when the OBS is set to the reciprocal.

Dead reckoning: GS = distance ÷ time; fuel required = (distance ÷ GS) × hourly fuel flow; always cross-check with at least one other navigation source.

Before take-off: complete the checklist, confirm take-off clearance, check runway and wind, set transponder, and brief the rejected take-off and emergency actions.

Wake turbulence: separation minima depend on aircraft weight categories; avoid the vortices by landing beyond the preceding aircraft's touchdown point and departing before its rotation point.

Engine failure after take-off: lower the nose to maintain best glide speed, select a landing area within reach, then attempt restart only if altitude and time permit.

Emergency descent: use maximum descent rate consistent with structural and passenger limits; set transponder 7700 and broadcast on 121.5 MHz.

Radio failure in VMC: continue under VFR, land at the nearest suitable aerodrome and report; in IMC, follow the published lost-communication procedure (typically last assigned route and level).

Fire: shut off fuel and electrical supply to the affected engine, use the extinguisher, and land as soon as practicable; do not restart a fire-affected engine.

Runway incursion avoidance: read back hold-short instructions, confirm the runway designator, and use the sterile cockpit rule during taxi and below 10,000 ft.

Lift L = ½ ρ V² S CL; lift rises with the square of speed, so doubling speed quadruples lift at a constant angle of attack.

Angle of attack is the angle between the chord line and the relative airflow; the critical angle (typically 15-18°) gives maximum lift and then stalls.

Stall speed varies with the square root of the load factor: at 2 g the stall speed increases by about 41% (√2).

Induced drag decreases with speed while parasite drag increases with the square of speed; total drag is minimum at the speed where the two are equal (best glide/L/D max).

Load factor n = 1 / cos(bank angle) in a level turn; at 60° bank n = 2, and the stall speed rises accordingly.

Asymmetric thrust: with the critical engine failed, the yaw is greater because of P-factor; VMC is the minimum control speed with the critical engine inoperative.

Stability: positive static stability means a disturbance produces a restoring force; dihedral gives lateral stability; the horizontal stabiliser gives longitudinal stability.

Ground effect occurs within about one wingspan of the surface, reducing induced drag and allowing take-off or landing at lower speed or thrust.