Mauritius DCA IR Theory cheat sheet

IFR flight in controlled airspace requires an ATC clearance; the clearance is an authorisation, not a guarantee of terrain or obstacle separation except where a radar service is explicitly provided.

Standard semicircular cruising levels: track 000–179 use odd thousands (FL090, FL110...); track 180–359 use even thousands (FL100, FL120...) - magnetic track, with the table published in the State AIP.

In Class C airspace IFR flights are separated from all other IFR and from VFR flights, and receive traffic information about VFR; in Class D IFR flights are separated from other IFR only.

Position reports are required at compulsory reporting points; the standard report contains aircraft identification, position, time, flight level, next position and ETA, and the following significant point.

A readback is mandatory for clearances, level instructions, heading/speed instructions, runway-in-use, altimeter settings and frequency changes - failure to read back does not validate the instruction.

Lost communication in IMC: maintain last assigned level and route, squawk 7600, attempt contact on the last frequency then the emergency frequency 121.5, and comply with the published lost-comm procedure.

Minimum fuel is an advisory declaring that landing at the destination below 30 minutes of final reserve fuel may occur; MAYDAY FUEL is an emergency declaring landing below final reserve.

An IFR flight plan must include alternate aerodrome requirements: an alternate is required when destination weather is at or near the published approach minima or when no instrument approach is available.

Pitot-static blockage: blocked pitot with static clear gives airspeed that behaves like an altimeter (climbs in climb); blocked static gives airspeed over-reading in climb and under-reading in descent.

Alternate static source is used when the static port is blocked; expect airspeed and altitude errors until the aircraft is in level flight and the system equalises.

Gyroscopic attitude and heading indicators are typically vacuum- or electrically driven; loss of a vacuum pump leaves the turn coordinator (electrically driven) as the surviving rate instrument.

An unsafe or failed gyro is flagged by a red 'GYRO' or 'ATT' flag on an electronic attitude display; reversion to the standby instrument follows the published abnormal checklist.

Pitot heat is switched on before entering visible moisture or icing conditions and during climb/descent through cloud; ammeter or loadmeter indications confirm heater operation.

The standby attitude indicator has its own power source and must be checked for caging/uncaging and erection before flight and periodically in cruise.

Autopilot minimum-use height is normally 200 ft AGL for approach coupler engagement unless the AFM states otherwise; the pilot must monitor and be able to disconnect instantly.

EFIS/glass cockpit failure modes: display unit failure, symbol generator failure and air data computer failure produce different reversionary displays; know the aircraft-specific reversionary panel.

Density altitude = pressure altitude + 120 × (OAT − ISA temperature at that level); performance charts are entered with pressure altitude and temperature, not QNH and elevation.

Landing distance required = landing distance available minus the regulatory factor; for a dry runway the required landing distance must not exceed 60% of LDA (i.e. 1.67× factor) under the applicable rule set.

Take-off obstacle clearance: the net take-off flight path is the gross gradient reduced by 0.8% (twin-engine) or 0.9% (three-engine) or 1.0% (four-engine).

Fuel planning: taxi fuel + trip fuel + contingency (typically 5% of trip fuel) + alternate fuel + final reserve (30 min holding at 1500 ft above aerodrome) + additional fuel.

Mass and balance: CG forward of the forward limit increases stick force and stall speed and reduces performance; aft of the aft limit reduces static stability and can cause pitch-up.

Climb gradient (%) = (altitude gained ÷ horizontal distance) × 100; gradient to 1000 ft = 1000 ÷ (ground distance to 1000 ft) × 100.

True airspeed increases about 2% per 1000 ft for a constant IAS in the lower atmosphere; ground speed combines TAS with wind component along track.

Contaminated runway braking action is reported as good, medium, poor or nil; nil means the runway is not usable and a diversion must be planned.

Hypoxia symptoms above 10 000 ft: euphoria, impaired judgement, cyanosis, headache, and loss of colour vision; time of useful consciousness at FL350 is about 30–60 seconds.

Spatial disorientation is most likely in the absence of visual references during acceleration, deceleration and bank entry; trust the instruments, not sensations.

The somatogravic illusion causes a false sensation of pitch-up during acceleration (e.g. take-off) and pitch-down during deceleration.

Leans illusion occurs after a sudden return to level flight from a sustained bank, causing the pilot to lean into the perceived bank.

Fatigue: circadian low points occur around 0300–0600 and 1500–1700 local; sleep debt and time-on-task degrade vigilance and increase error rates.

Crew resource management: assertiveness, situational awareness, workload distribution and cross-checking reduce single-pilot error; the captain retains final authority.

Decompression: don oxygen masks first, then descend to FL100 or the lowest safe level; the aircraft must be at a safe altitude before cabin crew are released.

ISA: sea level 15 °C and 1013.25 hPa, lapse rate 1.98 °C per 1000 ft up to the tropopause; pressure altitude = elevation + 30 ft per hPa below 1013.

QNH gives altitude above mean sea level; QFE gives height above the aerodrome reference point; the transition altitude/level is where the altimeter is reset to standard.

TAF: BECMG indicates a gradual change over a period, TEMPO indicates temporary fluctuations, and FM indicates an abrupt change at a stated time.

Icing risk: most severe in the 0 °C to −15 °C band in stratiform cloud; freezing rain and supercooled large droplets produce rapid airframe icing.

Thunderstorm life cycle: cumulus (updrafts), mature (updrafts and downdrafts, hail, lightning, gust front), dissipating (downdrafts).

Wind shear on approach: go-around is the correct response to a sudden airspeed loss or sink rate increase below 1000 ft AGL; do not chase the glideslope.

Low-level jet and mountain wave produce turbulence and downdrafts; mountain wave downdrafts can exceed the aircraft's climb capability.

VOR: the CDI shows course deviation, and TO/FROM is determined by the OBS setting; a 1° deviation equals about 1 NM per 60 NM from the station.

NDB/ADF: the ADF needle points to the station relative to the aircraft heading, so the bearing to the station = heading + relative bearing.

ILS localiser gives lateral guidance on 108.10–111.95 MHz; the glideslope is normally 3° and is transmitted on UHF, so a separate receiver is needed.

Marker beacons: outer marker (blue, ~4 NM) at glideslope intercept, middle marker (amber, ~3500 ft from threshold), inner marker (white).

RNAV/GNSS: RNP AR approaches require specific approval and crew training; LNAV/VNAV minima require baro-VNAV or SBAS; LPV requires SBAS.

RAIM predicts whether enough GNSS satellites are available for the required integrity; a RAIM check is mandatory before an RNP approach.

Holding pattern entry: direct, parallel or teardrop, chosen by the aircraft heading relative to the inbound holding course and the holding side.

Before take-off: verify the departure clearance, initial altitude, heading, frequency, squawk and any noise-abatement procedure; brief the rejected take-off decision.

SID: fly the published lateral and vertical profile; if given 'climb via SID' the published altitude restrictions apply; 'climb and maintain' cancels them.

Approach briefing: type of approach, minima, missed approach, go-around callouts, and the stabilised approach criteria (typically 1000 ft IMC / 500 ft VMC).

Stabilised approach: on speed, on profile, on centreline, landing checklist complete and thrust set by 1000 ft in IMC; otherwise go around.

Missed approach: apply power, pitch for the published climb gradient, follow the missed approach track, and do not turn before the MAPt unless the procedure permits.

Precision approach: decision altitude (DA) with a decision height (DH); non-precision: minimum descent altitude (MDA) with a missed approach point and level flight until the MAPt.

Go-around callouts: TOGA, positive climb, gear up, flaps as required, and the published missed approach; report the go-around to ATC.

Lift = ½ ρ V² S CL; at a constant IAS, lift is constant, so load factor increases with bank angle (n = 1/cos φ).

Stall speed increases with the square root of load factor: at 60° bank, stall speed is 1.41 times the 1 g stall speed.

Induced drag is proportional to CL² and inversely proportional to V²; total drag is minimum at the speed where induced drag equals parasite drag.

The lift coefficient increases with angle of attack up to the critical angle; a stall occurs at the critical angle regardless of speed or attitude.

Static stability: positive static stability means a disturbance produces a restoring moment; the horizontal stabiliser provides longitudinal stability.

Mach number = TAS / local speed of sound; the speed of sound is about 661 kt at sea level ISA and decreases with temperature.

In a turn, the horizontal component of lift provides the centripetal force; the vertical component must equal weight, hence the need for increased lift and back pressure.

IFR flight in controlled airspace requires an ATC clearance; the clearance is an authorisation, not a guarantee of terrain or obstacle separation except where a radar service is explicitly provided.

Standard semicircular cruising levels: track 000–179 use odd thousands (FL090, FL110...); track 180–359 use even thousands (FL100, FL120...) - magnetic track, with the table published in the State AIP.

In Class C airspace IFR flights are separated from all other IFR and from VFR flights, and receive traffic information about VFR; in Class D IFR flights are separated from other IFR only.

Position reports are required at compulsory reporting points; the standard report contains aircraft identification, position, time, flight level, next position and ETA, and the following significant point.

A readback is mandatory for clearances, level instructions, heading/speed instructions, runway-in-use, altimeter settings and frequency changes - failure to read back does not validate the instruction.

Lost communication in IMC: maintain last assigned level and route, squawk 7600, attempt contact on the last frequency then the emergency frequency 121.5, and comply with the published lost-comm procedure.

Minimum fuel is an advisory declaring that landing at the destination below 30 minutes of final reserve fuel may occur; MAYDAY FUEL is an emergency declaring landing below final reserve.

An IFR flight plan must include alternate aerodrome requirements: an alternate is required when destination weather is at or near the published approach minima or when no instrument approach is available.

Pitot-static blockage: blocked pitot with static clear gives airspeed that behaves like an altimeter (climbs in climb); blocked static gives airspeed over-reading in climb and under-reading in descent.

Alternate static source is used when the static port is blocked; expect airspeed and altitude errors until the aircraft is in level flight and the system equalises.

Gyroscopic attitude and heading indicators are typically vacuum- or electrically driven; loss of a vacuum pump leaves the turn coordinator (electrically driven) as the surviving rate instrument.

An unsafe or failed gyro is flagged by a red 'GYRO' or 'ATT' flag on an electronic attitude display; reversion to the standby instrument follows the published abnormal checklist.

Pitot heat is switched on before entering visible moisture or icing conditions and during climb/descent through cloud; ammeter or loadmeter indications confirm heater operation.

The standby attitude indicator has its own power source and must be checked for caging/uncaging and erection before flight and periodically in cruise.

Autopilot minimum-use height is normally 200 ft AGL for approach coupler engagement unless the AFM states otherwise; the pilot must monitor and be able to disconnect instantly.

EFIS/glass cockpit failure modes: display unit failure, symbol generator failure and air data computer failure produce different reversionary displays; know the aircraft-specific reversionary panel.

Density altitude = pressure altitude + 120 × (OAT − ISA temperature at that level); performance charts are entered with pressure altitude and temperature, not QNH and elevation.

Landing distance required = landing distance available minus the regulatory factor; for a dry runway the required landing distance must not exceed 60% of LDA (i.e. 1.67× factor) under the applicable rule set.

Take-off obstacle clearance: the net take-off flight path is the gross gradient reduced by 0.8% (twin-engine) or 0.9% (three-engine) or 1.0% (four-engine).

Fuel planning: taxi fuel + trip fuel + contingency (typically 5% of trip fuel) + alternate fuel + final reserve (30 min holding at 1500 ft above aerodrome) + additional fuel.

Mass and balance: CG forward of the forward limit increases stick force and stall speed and reduces performance; aft of the aft limit reduces static stability and can cause pitch-up.

Climb gradient (%) = (altitude gained ÷ horizontal distance) × 100; gradient to 1000 ft = 1000 ÷ (ground distance to 1000 ft) × 100.

True airspeed increases about 2% per 1000 ft for a constant IAS in the lower atmosphere; ground speed combines TAS with wind component along track.

Contaminated runway braking action is reported as good, medium, poor or nil; nil means the runway is not usable and a diversion must be planned.

Hypoxia symptoms above 10 000 ft: euphoria, impaired judgement, cyanosis, headache, and loss of colour vision; time of useful consciousness at FL350 is about 30–60 seconds.

Spatial disorientation is most likely in the absence of visual references during acceleration, deceleration and bank entry; trust the instruments, not sensations.

The somatogravic illusion causes a false sensation of pitch-up during acceleration (e.g. take-off) and pitch-down during deceleration.

Leans illusion occurs after a sudden return to level flight from a sustained bank, causing the pilot to lean into the perceived bank.

Fatigue: circadian low points occur around 0300–0600 and 1500–1700 local; sleep debt and time-on-task degrade vigilance and increase error rates.

Crew resource management: assertiveness, situational awareness, workload distribution and cross-checking reduce single-pilot error; the captain retains final authority.

Decompression: don oxygen masks first, then descend to FL100 or the lowest safe level; the aircraft must be at a safe altitude before cabin crew are released.

ISA: sea level 15 °C and 1013.25 hPa, lapse rate 1.98 °C per 1000 ft up to the tropopause; pressure altitude = elevation + 30 ft per hPa below 1013.

QNH gives altitude above mean sea level; QFE gives height above the aerodrome reference point; the transition altitude/level is where the altimeter is reset to standard.

TAF: BECMG indicates a gradual change over a period, TEMPO indicates temporary fluctuations, and FM indicates an abrupt change at a stated time.

Icing risk: most severe in the 0 °C to −15 °C band in stratiform cloud; freezing rain and supercooled large droplets produce rapid airframe icing.

Thunderstorm life cycle: cumulus (updrafts), mature (updrafts and downdrafts, hail, lightning, gust front), dissipating (downdrafts).

Wind shear on approach: go-around is the correct response to a sudden airspeed loss or sink rate increase below 1000 ft AGL; do not chase the glideslope.

Low-level jet and mountain wave produce turbulence and downdrafts; mountain wave downdrafts can exceed the aircraft's climb capability.

VOR: the CDI shows course deviation, and TO/FROM is determined by the OBS setting; a 1° deviation equals about 1 NM per 60 NM from the station.

NDB/ADF: the ADF needle points to the station relative to the aircraft heading, so the bearing to the station = heading + relative bearing.

ILS localiser gives lateral guidance on 108.10–111.95 MHz; the glideslope is normally 3° and is transmitted on UHF, so a separate receiver is needed.

Marker beacons: outer marker (blue, ~4 NM) at glideslope intercept, middle marker (amber, ~3500 ft from threshold), inner marker (white).

RNAV/GNSS: RNP AR approaches require specific approval and crew training; LNAV/VNAV minima require baro-VNAV or SBAS; LPV requires SBAS.

RAIM predicts whether enough GNSS satellites are available for the required integrity; a RAIM check is mandatory before an RNP approach.

Holding pattern entry: direct, parallel or teardrop, chosen by the aircraft heading relative to the inbound holding course and the holding side.

Before take-off: verify the departure clearance, initial altitude, heading, frequency, squawk and any noise-abatement procedure; brief the rejected take-off decision.

SID: fly the published lateral and vertical profile; if given 'climb via SID' the published altitude restrictions apply; 'climb and maintain' cancels them.

Approach briefing: type of approach, minima, missed approach, go-around callouts, and the stabilised approach criteria (typically 1000 ft IMC / 500 ft VMC).

Stabilised approach: on speed, on profile, on centreline, landing checklist complete and thrust set by 1000 ft in IMC; otherwise go around.

Missed approach: apply power, pitch for the published climb gradient, follow the missed approach track, and do not turn before the MAPt unless the procedure permits.

Precision approach: decision altitude (DA) with a decision height (DH); non-precision: minimum descent altitude (MDA) with a missed approach point and level flight until the MAPt.

Go-around callouts: TOGA, positive climb, gear up, flaps as required, and the published missed approach; report the go-around to ATC.

Lift = ½ ρ V² S CL; at a constant IAS, lift is constant, so load factor increases with bank angle (n = 1/cos φ).

Stall speed increases with the square root of load factor: at 60° bank, stall speed is 1.41 times the 1 g stall speed.

Induced drag is proportional to CL² and inversely proportional to V²; total drag is minimum at the speed where induced drag equals parasite drag.

The lift coefficient increases with angle of attack up to the critical angle; a stall occurs at the critical angle regardless of speed or attitude.

Static stability: positive static stability means a disturbance produces a restoring moment; the horizontal stabiliser provides longitudinal stability.

Mach number = TAS / local speed of sound; the speed of sound is about 661 kt at sea level ISA and decreases with temperature.

In a turn, the horizontal component of lift provides the centripetal force; the vertical component must equal weight, hence the need for increased lift and back pressure.