Mauritius DCA ATPL Theory cheat sheet

ICAO Annex 2 (Rules of the Air) applies over the high seas and, unless a State files differences, over Contracting States; national AIP differences prevail in national airspace.

VMC minima in Class C–E airspace at and above 3 050 m (10 000 ft) AMSL: 8 km flight visibility, 1 500 m horizontally and 300 m (1 000 ft) vertically from cloud.

Below 3 050 m AMSL in Class C–E: 5 km visibility, 1 500 m horizontally and 300 m vertically from cloud; at and below 900 m AMSL or 300 m above terrain (whichever is higher) in Class F/G: 5 km visibility, clear of cloud and in sight of surface.

Semi-circular rule: magnetic tracks 000–179° use odd flight levels (FL 090, 110, 130…); 180–359° use even flight levels (FL 100, 120…); IFR uses the same rule with RVSM levels.

Aircraft on final approach or landing have right of way over aircraft in flight or on the ground; an aircraft on the ground must give way to aircraft in flight and to aircraft taxiing.

Converging head-on: both turn right. Converging at roughly the same level: the aircraft with the other on its right gives way; overtaking aircraft keeps clear to the right.

An aircraft in distress has right of way over all other traffic; distress signal MAYDAY (voice) or SOS (Morse), urgency signal PAN PAN.

Position reports to ATC contain: aircraft identification, position, time, flight level or altitude, next position and ETA, and the succeeding significant point.

An ATC clearance does not relieve the pilot-in-command from responsibility for terrain clearance, wake-turbulence separation, or compliance with the rules of the air.

Aircraft electrical buses: a bus bar is a common supply point; essential/emergency buses are fed from the battery or a standby generator to keep flight instruments and radios alive.

A 28 V DC system on a typical light twin is fed by one generator per engine; both generators feed the bus through reverse-current relays so a failed generator is automatically isolated.

A NiCd battery requires a constant-voltage charge characteristic; a lead-acid battery requires constant-current charging; mixing charge regimes shortens life and can cause thermal runaway.

Aircraft circuit breakers are rated to protect wiring, not equipment: the breaker must trip before the cable's current-carrying capacity is exceeded.

Turbine engine EGT/ITT is limited because it reflects turbine blade temperature; an over-temperature limit is a hard limit, not a target.

Hydraulic systems use a pressure relief valve to protect against overpressure and an accumulator to damp pressure surges and supply short-term demand.

A fire in an engine compartment is normally handled by shutting off fuel, air and ignition, then discharging the fire bottle; a fire in a cargo hold uses the built-in extinguishing system.

Aircraft oxygen systems: diluter-demand masks supply oxygen in proportion to altitude; above 10 000 ft cabin altitude supplemental oxygen is required for flight crew.

Altimeter errors: pressure error (static port position), instrument error, temperature error; a cold temperature error makes the altimeter over-read, i.e. true altitude is lower than indicated.

Pitot-static: the airspeed indicator measures dynamic pressure (total minus static); a blocked pitot tube with open static makes the ASI behave like an altimeter as the aircraft climbs.

A blocked static port makes the ASI over-read in a climb and under-read in a descent; the altimeter freezes at the altitude at which the blockage occurred.

VSI measures rate of change of static pressure through a calibrated leak; a lag of several seconds is normal and is why the VSI is not used as a primary pitch instrument.

Gyroscopic instruments: rigidity in space gives attitude and heading reference; precession allows the turn indicator to sense rate of turn.

A turn coordinator shows rate of turn and roll; the turn needle (rate gyro) shows rate of turn only; a standard rate turn is 3°/s, i.e. 180° in one minute.

A magnetic compass has turning and acceleration errors: it under-reads on turns through north and over-reads on turns through south in the northern hemisphere.

Radio altimeters measure height above terrain using a frequency-modulated continuous-wave signal; they are only reliable below about 2 500 ft AGL.

An Air Data Computer combines pitot-static, temperature and angle-of-attack data to output computed airspeed, Mach, altitude and vertical speed to the displays.

Mass and balance: basic empty mass + crew + payload + fuel = take-off mass; landing mass = take-off mass − trip fuel.

Maximum zero-fuel mass is the maximum mass with no usable fuel aboard; it limits structural loading of the fuselage and wing root.

Centre of gravity position is found by dividing total moment by total mass; moments are mass × arm, with the datum as reference.

Loading a mass aft of the CG moves the CG aft; the shift is proportional to the mass and its distance from the original CG.

Forward CG limits: increased stick force, longer take-off run, higher stall speed, reduced range; aft CG limits: reduced stability and possible pitch-up.

The CG envelope is bounded by forward and aft limits that vary with mass; the aft limit is often most restrictive at high mass for swept-wing aircraft.

Fuel burn shifts the CG: fuel in wing tanks near the CG has little effect, fuel in fuselage tanks forward or aft of the CG moves it as it burns.

Use the load sheet to verify that take-off and landing masses and the CG for both are inside the envelope before flight.

Take-off distance required = ground roll + airborne distance to 35 ft; the balanced field length is the shorter of the accelerate-stop and accelerate-go distances.

V1 is the decision speed; VR is rotation speed; V2 is take-off safety speed, at least 1.13 VSR (stall speed in the take-off configuration).

Landing distance required is measured from 50 ft above the threshold to a full stop, multiplied by a factor of 1.67 for dry runways (1.92 for wet) in CS/FAR 25 certification.

Density altitude increases with temperature and pressure altitude; it raises true airspeed for a given IAS and lengthens take-off and landing distances.

Headwind decreases ground roll and take-off distance; tailwind increases them; a 10 % increase in mass increases the take-off distance by roughly 20 %.

Climb gradient % = (height gained / horizontal distance) × 100; rate of climb = gradient × ground speed.

V speeds vary with mass: V1 and VR increase with mass; VREF increases with the square root of mass.

Runway slope and surface condition (dry, wet, contaminated) are applied as corrections to the certified distances; contaminated runways require the contaminated-distance data.

Trip fuel = fuel from take-off to landing at destination; contingency fuel is normally 5 % of trip fuel; alternate fuel covers destination to alternate plus approach and missed approach.

Final reserve fuel for IFR is 30 minutes holding at 1 500 ft above the alternate; for VFR it is 45 minutes at normal cruise.

Total fuel = taxi + trip + contingency + alternate + final reserve + additional/extra fuel; the minimum take-off fuel is the sum without taxi.

Point of no return (equal-time point): time to PNR = (fuel available × TAS) / (2 × fuel flow) for a still-air case; it marks the last point from which a return is possible.

Equal-time point to a destination and a diversion airfield uses the same principle with different groundspeeds: distance = (total distance × groundspeed out) / (groundspeed out + groundspeed back).

Fuel flow (kg/h) = power or thrust setting × specific fuel consumption; specific range (nm/kg) = TAS / fuel flow.

In-flight monitoring: compare actual fuel against planned fuel at each waypoint; a discrepancy of more than 5 % requires a re-plan and possibly a diversion decision.

Flight plan cruising levels follow the semi-circular rule by magnetic track; the flight plan must be filed at least 60 minutes before departure for IFR in most States.

Hypoxia: above 10 000 ft cabin altitude supplemental oxygen is required; time of useful consciousness at FL 350 is about 30–60 seconds, at FL 250 about 3–5 minutes.

Hyperventilation causes dizziness, tingling and blurred vision; it is treated by slowing the breathing rate, not by breathing more oxygen.

Spatial disorientation: the somatogravic illusion makes an acceleration feel like a climb; the leans and Coriolis illusion arise from the semicircular canals.

Night vision uses rods, which are most sensitive to blue-green light and need 30 minutes for full dark adaptation; use off-centre viewing to see dim objects.

Cabin decompression: don the mask first, then check the passenger masks; the oxygen mask must be sealed and the regulator set to 100 %.

ISA: sea-level temperature 15 °C, pressure 1013.25 hPa, lapse rate 1.98 °C per 1 000 ft up to 36 090 ft (tropopause, −56.5 °C).

Pressure altitude = indicated altitude corrected for the altimeter subscale setting; true altitude = pressure altitude corrected for temperature error.

QNH is the pressure reduced to sea level; QFE is the pressure at the aerodrome reference point; the standard setting 1013.25 hPa is used above the transition altitude.

The tropopause is higher and colder at the equator (about 55 000 ft) than at the poles (about 30 000 ft); the jet stream lies near the tropopause.

A cold front has a steep slope, narrow band of heavy showers, thunderstorms and a sharp wind veer; a warm front has a shallow slope and widespread stratiform cloud and drizzle.

Icing: clear ice forms in large supercooled droplets at 0 to −10 °C; rime ice forms in small droplets at −10 to −20 °C; freezing rain is the most dangerous.

Wind shear on final approach is reported as a microburst or gust front; a sudden increase in headwind causes the aircraft to balloon above the glide path.

Thunderstorm life cycle: cumulus (updrafts), mature (updrafts and downdrafts, lightning, hail), dissipating (downdrafts); avoid by at least 10 nm.

Great circle: the shortest path between two points on a sphere; its track changes continuously and it crosses each meridian at a different angle.

Rhumb line: a line of constant track that crosses every meridian at the same angle; it is longer than the great circle except along the equator or a meridian.

Departure (nm) = change of longitude (minutes) × cos(latitude); 1 minute of latitude = 1 nm.

The heading is the direction the aircraft points; the track is the path over the ground; drift = track − heading.

Magnetic variation is the angle between true and magnetic north; easterly variation is subtracted from true to get magnetic.

Dead reckoning: track made good = heading + drift; ground speed = distance / time; the wind triangle uses TAS, heading, wind direction and speed.

The 1-in-60 rule: a 1° error over 60 nm produces a 1 nm lateral error; use it for off-track corrections.

A Lambert conformal conic chart is conformal, so angles are correct; the scale is constant along a standard parallel and varies away from it.

VOR: the aircraft's OBS selects a radial; the CDI centres when the selected radial matches the aircraft's bearing from the station; TO/FROM indicates the direction.

DME measures slant range; at high altitude the slant range exceeds the ground distance, and the error is small only when the aircraft is close to the station.

ILS localiser gives lateral guidance on 108.10–111.95 MHz (odd tenths); the glideslope gives vertical guidance on 329.15–335.00 MHz and is normally 3°.

Marker beacons: outer marker at about 4 nm (400 Hz), middle marker at about 3 500 ft (1 300 Hz), inner marker at the threshold (3 000 Hz).

NDB/ADF: the ADF needle points to the station; the relative bearing plus the heading gives the magnetic bearing to the station.

GNSS: RAIM monitors integrity; a RAIM prediction is required before an RNP approach, and RAIM availability depends on the satellite geometry.

Transponder codes: 7500 unlawful interference, 7600 radio failure, 7700 emergency; Mode C reports pressure altitude.

Take-off briefing covers: V speeds, engine failure actions, rejected take-off decision, emergency return, terrain and obstacles, and the departure route.

An engine failure after V1: maintain directional control, pitch for V2, identify and confirm the failed engine, feather it, and clean up only when a safe climb is assured.

Approach briefing includes: type of approach, minima, missed approach, go-around decision height, and the runway exit plan.

Emergency descent: don masks, set 100 % oxygen, establish the emergency descent speed, turn off the cabin altitude warning, and descend to 10 000 ft or the MSA.

A rejected take-off is mandatory before V1 for a serious engine failure, fire, or loss of directional control; after V1 the take-off is continued unless the aircraft cannot fly.

CRM: briefings, callouts, workload sharing and assertiveness; a challenge must be answered, not ignored, and the captain remains responsible for the decision.

A pilot incapacitation: the other pilot takes control, uses the autopilot, and follows the standard callouts; a cabin crew member may be asked to assist.

Lift L = ½ ρ V² S CL; induced drag Di = L² / (½ ρ V² π b² e), so induced drag falls with increasing speed and rises with mass.

Stall occurs at the critical angle of attack, which is independent of mass, bank angle and density altitude; the stall speed rises with mass, load factor and altitude.

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

The centre of pressure moves aft as angle of attack increases on a cambered wing; a swept wing has a pitch-up tendency at the stall.

Boundary layer: laminar flow has low skin friction but separates easily; turbulent flow has higher friction but resists separation, which is why vortex generators delay the stall.

Mach critical is the free-stream Mach number at which local airflow first reaches Mach 1; it decreases with increasing thickness/chord ratio and lift coefficient.

Dihedral gives lateral stability: a sideslip causes the lower wing to meet the airflow at a higher angle of attack, producing a rolling moment that levels the wings.

Aspect ratio = span² / area; a high aspect ratio reduces induced drag, which is why gliders have long, narrow wings.