Oman CAA ATPL(A) Theory cheat sheet

ICAO Annex 2 (Rules of the Air) applies over the high seas and, unless otherwise stated in national law, over Contracting States' territories.

Semi-circular rule: magnetic tracks 000-179 use odd thousands (FL); 180-359 use even thousands, with RVSM applying 290-410.

VMC minima in Class C airspace above 3050 m (10000 ft) AMSL: 8 km flight visibility, 1500 m horizontal and 300 m (1000 ft) vertical distance from cloud.

Class A airspace is IFR only; Class F is advisory, where IFR and VFR may mix and ATC separation is not provided to IFR from VFR.

Aircraft on final approach or landing have right of way over aircraft in flight or on the ground; an aircraft landing has priority over one taxiing.

Emergency frequency 121.5 MHz; distress call 'MAYDAY' (three times), urgency call 'PAN PAN' (three times).

Aircraft must not fly over congested areas below 300 m (1000 ft) above the highest obstacle within 600 m of the aircraft.

Position reports include aircraft identification, position, time, altitude/flight level, next position and ETA; omit items already passed to ATC.

A gas-turbine compressor surge is caused by excessive angle of attack of compressor blades, often from abrupt throttle movement or disturbed intake airflow.

Bleed air for pressurisation and anti-ice is normally tapped from the HP compressor stage; excessive bleed extraction reduces engine thrust margin.

Hydraulic systems use pressure relief valves to cap pressure and accumulators to damp pressure surges and supply transient demand.

Aircraft DC electrical systems on transport aircraft typically use 28 V DC; AC systems commonly 115 V AC at 400 Hz.

The landing-gear downlock is confirmed by mechanical locks and indicated by green lights; red or no-light indicates unsafe condition.

Fire detection in engines typically uses continuous-loop sensing elements; a single-loop failure must not cause a false fire warning.

Pitot heat failure or blockage produces erroneous airspeed indication; static blockage affects airspeed, altitude and vertical speed simultaneously.

A constant-speed propeller maintains RPM by varying blade angle; an overspeed governor prevents RPM exceeding limits.

The altimeter is a barometer calibrated to ISA; setting QNH gives altitude above mean sea level, QFE gives height above the datum.

Altimeter error: flying from high to low pressure without resetting the subscale causes the aircraft to be lower than indicated.

The airspeed indicator measures dynamic pressure (total minus static); it under-reads at altitude for a given TAS because of lower air density.

A Machmeter uses pitot and static pressures to compute M = TAS/a; it is unaffected by density error in the same way as the ASI.

Turn coordinator shows rate of turn and roll; the turn-and-slip indicator shows rate of turn only.

An artificial horizon gyro relies on rigidity in space; erection errors cause a slow topple that must be corrected by caging or slaving.

The magnetic compass is affected by turning and acceleration errors; it is most reliable in straight and level, unaccelerated flight.

Radio altimeters measure height above terrain using frequency-modulated continuous-wave or pulse techniques, typically valid up to 2500 ft.

Maximum take-off mass = maximum zero-fuel mass + usable fuel; maximum landing mass is normally lower than MTOM.

CG position is found by summing moments (mass × arm) and dividing by total mass; arms measured from the datum.

The forward CG limit is set by elevator authority for rotation and landing flare; the aft limit by static and dynamic stability.

Load sheet: dry operating mass includes crew, crew baggage and unusable fuel; traffic load = passengers + baggage + cargo.

Moving mass forward or aft shifts the CG by (mass moved × distance moved) / total mass.

MTOM limited by runway length, climb gradient, obstacle clearance, tyre speed and brake energy, not only structural limits.

Zero-fuel mass must not exceed MZFM; fuel in tanks is added after ZFM check for take-off mass.

When adding mass at a point, the CG moves toward that point; the shift is proportional to the added mass and its arm.

V1 is the decision speed: after V1 a take-off must be continued; before V1 it must be rejected.

Balanced field length assumes the accelerate-stop distance equals the accelerate-go distance, giving minimum field length.

V2 is take-off safety speed, achieved by 35 ft; V2 min ensures a specified climb gradient with one engine inoperative.

Climb gradient (%) = (height gained / horizontal distance) × 100; 3.3% ≈ 200 ft/NM.

Density altitude increases with temperature and pressure altitude; higher density altitude reduces engine power and lift.

Landing distance required is the greater of the landing distance available considerations; a 1.67 factor is commonly applied to the demonstrated landing distance for dry runways.

V speeds vary with mass: V1 and VR increase with mass; V2 generally decreases slightly with mass increase for a given flap setting.

Take-off climb segments: first segment to 35 ft, second to 400 ft (flaps take-off), third to acceleration altitude; one-engine-inoperative gradients are prescribed.

Trip fuel covers taxi, climb, cruise, descent and approach; reserve fuel typically includes contingency, alternate and final reserve.

Specific range = distance per unit fuel (NM/kg); best specific range occurs near the speed for maximum lift/drag ratio.

Fuel flow increases with altitude decrease and with higher TAS; the optimum cruise altitude balances specific range against wind.

Wind effect: headwind increases trip fuel and time; the penalty is larger at lower TAS for a given wind component.

Pilot navigation log: legs, tracks, TAS, wind, heading, groundspeed, ETA and fuel; update with actuals in flight.

Equal time point (ETP) is where time to destination equals time back to departure; equal fuel point considers fuel burn.

Point of no return (PNR) is limited by fuel available to return; compute using outbound and return groundspeeds.

Descent planning: 3° path ≈ 300 ft/NM; required rate of descent (ft/min) ≈ groundspeed (kt) × 5.

Hypoxia symptoms: euphoria, impaired judgement, cyanosis, headache; time of useful consciousness falls rapidly above FL350.

Hyperventilation reduces CO2 and causes dizziness and tingling; treatment is controlled breathing and reassurance.

Spatial disorientation results from conflicting vestibular and visual cues; trust instruments in IMC.

The vestibular system senses angular acceleration (semicircular canals) and linear acceleration (otoliths); it cannot detect constant velocity.

Night vision uses rods, which are slow to adapt and poor at colour; avoid bright light to preserve dark adaptation.

Fatigue degrades vigilance, reaction time and decision-making; circadian low points occur around 0300-0500 and 1500-1700 local.

Cabin altitude above 10000 ft requires oxygen for crew; above 14000 ft for passengers in unpressurised aircraft.

Decompression sickness (bends) risk rises with altitude exposure after diving; observe surface intervals before flying.

ISA: sea level 15 °C and 1013.25 hPa; temperature lapse rate 1.98 °C/1000 ft up to 36089 ft (tropopause).

QNH is pressure reduced to sea level; QFE is station pressure; QFF is reduced to sea level using actual temperature.

Cold front: steep slope, rapid passage, cumuliform cloud, showers, squalls, good visibility behind.

Warm front: shallow slope, stratiform cloud, continuous precipitation, poor visibility ahead.

Wind veers with height in the northern hemisphere (Ekman spiral); backing is anticlockwise shift.

Fog forms when temperature reaches dewpoint; radiation fog needs clear skies, light wind and high humidity.

Jet streams are found near the tropopause; CAT is associated with strong wind shear and curved flow.

Thunderstorm life cycle: cumulus, mature (updrafts and downdrafts), dissipating; hail and microbursts occur in the mature stage.

Great circle: shortest distance between two points; track changes continuously; rhumb line maintains constant track.

1 minute of latitude = 1 NM; 1 minute of longitude = 1 NM × cos(latitude).

Mercator projection: rhumb lines are straight, great circles curve poleward; scale increases with latitude.

Lambert conformal conic: straight-line great circles approximately, good for mid-latitude charts.

Heading = track ± wind correction angle; drift = angle between heading and track.

Track error and closing angle: total correction = track error + closing angle; use 1-in-60 rule for small angles.

1-in-60 rule: distance off track = (track error in degrees / 60) × distance flown.

Sunrise/sunset and twilight depend on latitude and season; at high latitudes the sun may not set in summer.

VOR provides magnetic bearing (radial) from station; CDI centred with TO/FROM flag indicates on-radial.

DME measures slant range; indicated distance is greater than ground distance at high altitude and close range.

ILS localiser provides lateral guidance; glide path provides vertical guidance, typically 3°; marker beacons indicate distance.

NDB/ADF gives relative bearing; magnetic bearing = relative bearing + aircraft magnetic heading.

GPS uses trilateration from satellites; RAIM monitors integrity; required for precision approaches.

Transponder codes: 7700 emergency, 7600 radio failure, 7500 hijack; Mode C provides altitude.

Radar: primary uses skin return; secondary uses transponder interrogation; SSR provides range and azimuth.

RNAV/GNSS approach minima depend on SBAS/GBAS augmentation; LNAV, LNAV/VNAV and LPV classifications differ in vertical guidance.

Before take-off: check performance, mass and balance, fuel, weather, NOTAMs, alternate and take-off minima.

Engine failure after V1: maintain directional control, climb at V2, identify and secure failed engine, follow checklist.

Rejected take-off: close throttles, apply maximum braking, maintain directional control, use reverse thrust as available.

Emergency descent: use maximum rate, consider structural limits, oxygen masks, and notify ATC with MAYDAY.

Fire in flight: isolate systems, use extinguisher, plan diversion; do not restart an engine after fire unless required.

Cabin depressurisation: don oxygen masks, initiate emergency descent to 10000 ft or MSA, advise ATC.

Fuel management: monitor fuel against flight plan; declare minimum fuel and MAYDAY FUEL when appropriate.

Pre-flight: check MEL, fuel quantity, oxygen, fire extinguishers, emergency equipment and survival gear for the route.

Lift L = ½ ρ V² S CL; induced drag DI = L² / (½ ρ V² S π e AR).

Induced drag decreases with speed; parasite drag increases with V²; total drag minimum at best L/D speed.

Angle of attack is the angle between chord line and relative airflow; stall occurs at critical AoA regardless of speed.

Load factor n = L/W; stall speed increases with √n; accelerated stall at higher speed in turns.

Static stability requires CG forward of the neutral point; positive static stability means return toward equilibrium.

Flaps increase CL and drag, allowing lower approach speed; leading-edge devices delay stall by increasing critical AoA.

Mach effects: critical Mach number is where local airflow reaches M1; shock stall and tuck-under occur beyond it.

Dihedral provides lateral stability; sweepback improves high-speed performance but reduces lateral stability at high AoA.