WACE Aviation cheat sheet

Four-stroke cycle order: induction (intake), compression, power (combustion), exhaust; the crankshaft completes two revolutions per cycle.

Airframe primary structure carries flight, ground and pressurisation loads; secondary structure (fairings, cowlings) carries only aerodynamic or protective loads.

Hydraulic system pressure is regulated by a relief valve; a selector valve directs flow to actuators and a check valve prevents reverse flow.

Electrical buses are fed by the battery, engine-driven alternator/generator, and external power; essential buses isolate critical loads such as flight instruments.

Pitot-static system: pitot tube supplies total (ram) pressure, static port supplies ambient pressure; blockage of the static port causes airspeed to over-read in climb and under-read in descent.

Turbine engine thrust is produced by accelerating a mass of air; bypass ratio is bypass mass flow divided by core mass flow.

Landing gear: tricycle layout places the main gear behind the centre of gravity so braking produces a nose-down moment; a tailwheel layout is prone to ground looping.

Fuel system vents prevent tank collapse and allow fuel to flow; unusable fuel cannot be delivered in all flight attitudes and is excluded from usable fuel calculations.

Lift equation: L = ½ρV²SC_L; lift rises with the square of airspeed and linearly with air density and wing area.

Induced drag varies inversely with the square of airspeed and is largest at low speed and high angle of attack; parasite drag rises with the square of airspeed.

Total drag is minimum where induced drag equals parasite drag; this speed gives maximum lift-to-drag ratio and best glide range.

Critical angle of attack (typically near 15–18° for light aircraft) produces the stall regardless of airspeed, weight or bank angle.

Load factor n = L/W; in a level turn n = 1/cos(bank angle), so a 60° bank doubles the stall speed.

Stability: positive static stability means a disturbance produces a restoring force; the horizontal tail provides longitudinal (pitch) stability because it is behind the centre of gravity.

Bernoulli's theorem relates pressure, velocity and height along a streamline; in steady, incompressible flow a speed increase accompanies a pressure decrease.

Flaps increase camber and wing area, raising C_Lmax and lowering stall speed, but increase drag; retracting flaps reduces lift and can cause a sink if not compensated.

Conversions: 1 nautical mile = 1.852 km = 1.1508 statute miles; 1 knot = 1 nm per hour.

Great circle is the shortest path on a sphere; rhumb line crosses all meridians at a constant angle and plots as a straight line on a Mercator chart.

Track is the path over the ground; heading is where the nose points; drift = track minus heading (positive right).

Wind triangle: true airspeed and heading give heading vector, wind vector added gives ground speed and track; GS = TAS × cos(drift) adjusted for wind component.

1 in 60 rule: a 1° error over 60 nm displaces the aircraft about 1 nm off track.

Magnetic variation converts true to magnetic (variation east, magnetic least); deviation is the compass error caused by aircraft magnetic fields.

VOR gives magnetic bearing from the station (radial); DME gives slant range; a transponder provides pressure altitude and identity to ATC.

Time to a waypoint from a station: time = distance/ground speed; ETA = departure time + elapsed time along the route.

ISA: sea level temperature 15 °C, pressure 1013.25 hPa, lapse rate 1.98 °C per 1000 ft up to the tropopause (about 36,090 ft).

Pressure altitude = indicated altitude + 30 ft × (1013 − QNH in hPa); density altitude rises with high temperature, high humidity and low pressure.

QNH set on the subscale gives altitude above mean sea level; QFE gives height above the aerodrome reference point; standard pressure 1013.25 hPa is used above transition altitude.

Fuel required = taxi + trip + contingency + alternate + final reserve (typically 30 minutes holding for light aircraft).

Crosswind component = wind speed × sin(angle between wind and runway); headwind component = wind speed × cos(angle).

Cloud types by height: cirrus family high, altostratus/altocumulus middle, stratus/stratocumulus/cumulus low; cumulonimbus produces thunderstorms, icing and wind shear.

In the southern hemisphere, air flows anticlockwise around a high and clockwise around a low; Coriolis force deflects moving air to the left.

Cold fronts produce rapid lifting, narrow bands of heavy showers and a sharp wind shift; warm fronts give gradual lift and widespread steady rain.

The error chain model (the 'Swiss cheese' model) shows that accidents usually follow several failed defences rather than a single cause.

Threat and Error Management (TEM) counters threats, errors and undesired aircraft states; the countermeasure sequence is avoid, trap, mitigate.

A safety management system (SMS) has four pillars: safety policy, safety risk management, safety assurance and safety promotion.

Risk assessment multiplies likelihood by severity; hazards are ranked and controls applied at the highest-risk items first.

Runway incursion prevention: read back clearances, confirm hold-short instructions and maintain situational awareness on the manoeuvring area.

Sterile cockpit rules prohibit non-essential activity during taxi, take-off and landing; checklists are read aloud and challenged (challenge-and-response).

Wake turbulence is strongest behind heavy, slow, clean aircraft; separation is applied by ATC and by the pilot using rotation and touchdown points.

Just culture distinguishes human error (non-punitive) from reckless behaviour (subject to sanction), encouraging voluntary reporting.

Hypoxia symptoms include euphoria, impaired judgement, headache and cyanosis; time of useful consciousness falls sharply above 25,000 ft.

Hyperventilation produces dizziness and tingling; treatment is to slow the breathing rate and, if hypoxia is suspected, use supplemental oxygen.

Spatial disorientation arises when vestibular illusions conflict with instrument indications; the remedy is to trust the instruments and maintain a standard scan.

The decision-making models DECIDE and IM SAFE cover detect, estimate, choose, identify, do, evaluate, and illness, medication, stress, alcohol, fatigue, eating.

Alcohol: a common regulatory limit is a blood alcohol concentration below 0.02% (some states 0.00%), with no flying within 8 hours of consumption.

Fatigue degrades vigilance and reaction time; controlled rest and duty-time limits are regulatory mitigations.

Regulatory framework: ICAO sets standards and recommended practices in Annexes; national authorities (e.g. CASA) issue rules; the AIP publishes aerodrome and airspace data.

Medical certificates are class-based (Class 1 commercial, Class 2 private); currency requirements typically include recent take-offs and landings in the preceding 90 days.

Airspace classes: Class C requires ATC clearance and provides separation for IFR and VFR; Class G is uncontrolled with no separation service.

ATIS provides current aerodrome weather and operational information; the pilot reads back the identifying letter to ATC.

Clearance read-back is mandatory for runway, heading, altitude and frequency elements; 'line up and wait' is not a take-off clearance.

METAR is an aerodrome routine observation; TAF is an aerodrome forecast valid for a stated period; SPECI reports significant changes.

Phonetic alphabet: Alpha, Bravo, Charlie, Delta, Echo, Foxtrot, Golf, Hotel, India, Juliett, Kilo, Lima, Mike, November, Oscar, Papa, Quebec, Romeo, Sierra, Tango, Uniform, Victor, Whiskey, X-ray, Yankee, Zulu.

Squawk codes: 7700 emergency, 7600 radio failure, 7500 unlawful interference; 7000 is the standard VFR code in many regions.

Take-off and landing performance must account for runway length, slope, wind, temperature, pressure altitude and obstacle clearance.

Weight and balance: the centre of gravity must lie within limits; loading aft of the aft limit reduces pitch stability and can make recovery from a stall difficult.

Airline economic cycle: profitability is cyclical and sensitive to fuel price, load factor and yield (revenue per passenger-kilometre).

Hub-and-spoke networks concentrate traffic at hubs to raise load factors; point-to-point low-cost models reduce turnaround time and ancillary costs.

Aviation contributes roughly 2–3% of global CO2 emissions; efficiency measures include fleet renewal, sustainable aviation fuel and improved air traffic management.

Career path: student pilot licence, private licence (PPL), commercial licence (CPL) with instrument and multi-engine ratings, then airline type rating and line training.

Pilot roles progress from second officer or first officer to captain; command requires an air transport pilot licence and specified flight hours.

Ground careers include air traffic control, aircraft maintenance engineering, dispatch, safety management and airport operations.

Aviation governance: ICAO sets international standards, IATA represents airlines, and national regulators license personnel and certify aircraft.

Air cargo and general aviation are distinct segments; general aviation covers private, training, agricultural and charter operations.

Radio phraseology uses standard words: 'roger' means message received, 'wilco' means will comply, 'affirm' and 'negative' replace yes and no.

A position report typically contains identification, position, time, altitude and next position with ETA.

Emergency: MAYDAY (distress, three times) and PAN-PAN (urgency, three times); the distress message includes nature of emergency and intentions.

Lost communication: squawk 7600, maintain last assigned route, and follow published lost-communication procedures.

Altimeter setting: below transition altitude use local QNH; above it use standard 1013.25 hPa; transition layer separates the two.

Wind shear and microburst alerts require immediate go-around if encountered below 1000 ft on approach.

Runway designators are magnetic headings rounded to the nearest 10° divided by 10; parallel runways use L, C and R suffixes.

Aerodrome traffic circuit: dead side, crosswind, downwind, base and final legs; the downwind leg is flown parallel to the runway in the opposite direction to landing.

Climb gradient (%) = (height gained / horizontal distance) × 100; gradient in ft/nm = height gained in ft / distance in nm.

Rate of climb needed to achieve a gradient: ROC (ft/min) = gradient (ft/nm) × ground speed (nm/min).

True airspeed approximation: TAS ≈ IAS × (1 + 0.02 × altitude in thousands of feet) at constant temperature.

Density altitude approximation: add about 120 ft per 1 °C above ISA temperature at the aerodrome.

Endurance (h) = usable fuel / fuel flow; range (nm) = endurance × ground speed.

Point of no return: distance = (fuel available × ground speed out) / (ground speed out + ground speed back).

Top of descent distance ≈ height to lose (ft) / required descent gradient (ft/nm), e.g. 3° ≈ 318 ft/nm.

Wind component: headwind/tailwind = wind speed × cos(angle); crosswind = wind speed × sin(angle).