CAA NZ ATPL Theory - Flight Navigation General cheat sheet

DR position: advance last known fix by TAS and true heading for elapsed time; wind requires triangle of velocities solution.

1 in 60 rule: off-track distance = (distance flown × track error in degrees) / 60; also gives closing angle to destination.

Fuel required = (trip fuel + reserve + contingency + alternate + final reserve); final reserve 30 min at holding speed for turbine, 45 min for piston (NZ ATPL standard).

Endurance (hours) = usable fuel / hourly fuel flow; safe endurance subtracts fixed reserve before dividing.

Pilot navigation log: columns for leg, TAS, wind, heading, groundspeed, distance, time, fuel; check totals against endurance.

Equal time point (ETP): point where time to A equals time to B; ETP distance from A = (D × GS_B) / (GS_A + GS_B) for still-air or wind-adjusted groundspeeds.

Point of no return (PNR): distance = (endurance × GS_out × GS_back) / (GS_out + GS_back).

Critical fuel point: where fuel remaining equals fuel needed to divert to alternate plus reserves; compute with wind-adjusted groundspeeds.

Vector relationship: heading/TAS + wind velocity = track/groundspeed; solve with sine rule or E6B.

Wind correction angle (WCA): sin(WCA) = (wind speed × sin(wind angle to track)) / TAS; wind angle measured from nose or tail.

Headwind component = wind speed × cos(angle between wind and track); crosswind component = wind speed × sin(angle).

Drift = track minus heading (positive right); WCA = heading minus track (positive right).

Maximum drift occurs when wind is perpendicular to track; drift = arcsin(wind speed / TAS).

Groundspeed = TAS × cos(WCA) + wind component along track; for small WCA, GS ≈ TAS + headwind component.

When wind is from the left, heading must be turned left (into wind) to maintain track; from the right, turn right.

Use the 1 in 60 rule to estimate drift: drift ≈ (crosswind / TAS) × 60 degrees.

VOR: radial is magnetic bearing from station; CDI centered with TO/FROM indicates aircraft on that radial; OBS selects radial.

VOR line-of-sight: reception range ≈ 1.23 × √(height in feet) nautical miles; terrain and altitude affect.

DME: slant range; ground distance = √(DME² − height²); accuracy ±0.5 NM or 3% of distance.

NDB/ADF: relative bearing = angle from aircraft heading clockwise to station; magnetic bearing to station = heading + relative bearing.

ILS: localizer gives lateral guidance (108–112 MHz), glideslope (329–335 MHz) gives vertical; decision height at minima.

GNSS: RAIM detects faults; RAIM availability requires at least 5 satellites (or 6 for exclusion); WAAS/SBAS improves accuracy.

VOR accuracy ±1° to ±3°; NDB accuracy ±5° to ±10°; ILS localizer ±0.5°; DME ±0.5 NM.

Transponder code 7500 hijack, 7600 radio failure, 7700 emergency.

RNAV: navigation capability allowing aircraft to fly any desired flight path within coverage of navigation aids or self-contained means.

RNP: RNAV with on-board performance monitoring and alerting; required navigation performance (RNP) values specify lateral accuracy in NM.

PBN: area navigation based on performance requirements for aircraft operating along ATS routes, on instrument approach procedures, or in designated airspace.

RNAV 10 (RNP 10): oceanic/remote; RNAV 5: European B-RNAV; RNAV 2/1: terminal/en route; RNP 4: oceanic; RNP 1: terminal; RNP 0.3: helicopter.

Required sensors: GNSS, DME/DME, VOR/DME; FMS computes position and provides guidance; RAIM prediction required for GNSS-based RNAV.

RNAV approach: LNAV (lateral only), LNAV/VNAV (lateral + vertical), LP (localizer performance), LPV (localizer performance with vertical guidance).

Containment: RNP 1 requires 1 NM lateral accuracy; RNP 0.3 requires 0.3 NM; monitoring and alerting required.

AR (authorization required) approach: RNP AR with radius-to-fix legs; requires special crew and aircraft approval.

True bearing: measured clockwise from true north (0°–360°). Magnetic bearing: measured clockwise from magnetic north.

Variation: angle between true and magnetic north; east variation subtract from true to get magnetic, west variation add.

Mnemonic: Variation east, magnetic least (true − east = magnetic); Variation west, magnetic best (true + west = magnetic).

Compass deviation: error caused by aircraft magnetic fields; applied to magnetic to get compass heading; deviation card required.

Isogonals: lines of equal variation; agonic line: zero variation.

Magnetic heading = true heading ± variation (east subtract, west add); compass heading = magnetic heading ± deviation.

When converting true to magnetic: easterly variation is subtracted from true; westerly variation is added to true.

Magnetic dip: compass needle aligns with magnetic field; dip increases toward magnetic poles; causes turning errors in turns and acceleration errors.

Track: actual path over ground; heading: direction aircraft nose points; drift = track − heading.

True heading = true track ± drift (wind correction); magnetic heading = true heading ± variation.

Compass heading = magnetic heading ± deviation; deviation is specific to aircraft and compass.

To convert true track to magnetic track: apply variation (east subtract, west add).

To convert magnetic track to true track: apply variation (east add, west subtract).

Wind correction angle (WCA) is added to track to get heading: heading = track + WCA (positive right, negative left).

If wind from left, WCA is negative (turn left); if from right, WCA positive (turn right).

Use the 1 in 60 rule to estimate heading changes: degrees = (distance off track / distance flown) × 60.

Earth rotates 15° per hour; 1° longitude = 4 minutes time difference; 15' = 1 minute.

Local mean time (LMT) = UTC + (longitude / 15) hours; east longitude ahead of UTC, west behind.

UTC = LMT ± (longitude / 15); use east add, west subtract when converting LMT to UTC.

Standard time zones: roughly 15° wide; zone time = UTC + zone offset; daylight saving adds 1 hour.

Latitude: 1 minute of latitude = 1 nautical mile; longitude distance = 1 minute × cos(latitude).

Solar time: apparent solar time varies with equation of time; mean solar time uses average sun.

Great circle distance (NM) = 60 × angular distance in degrees; use spherical trigonometry or E6B.

Sunrise/sunset: approximate by LMT = 6h/18h ± equation of time and longitude correction; use tables for accuracy.

True altitude = indicated altitude + (pressure altitude − indicated altitude) + temperature correction.

Temperature correction: when temperature is colder than ISA, true altitude is lower than indicated; when warmer, higher.

Altimeter setting: QNH gives altitude above mean sea level; QFE gives height above aerodrome; QNE (1013.25 hPa) gives flight level.

High to low pressure: altimeter overreads when flying from high to low pressure (true altitude lower than indicated).

Wind: geostrophic wind flows parallel to isobars; surface friction causes wind to back and decrease in speed.

Jet streams: strong westerly winds at tropopause; affect groundspeed and fuel planning; clear air turbulence possible.

ISA: temperature 15°C at MSL, lapse rate 1.98°C per 1000 ft; pressure 1013.25 hPa.

Mountain waves: downdrafts and turbulence; altimeter errors due to non-standard pressure and temperature.

Oceanic tracks: organized track system (OTS) with daily tracks; MNPS (minimum navigation performance specifications) requires RNP 10 or better.

NAT HLA (North Atlantic High Level Airspace): requires RNP 4, RVSM, and CPDLC; tracks change twice daily.

Equal time point (ETP) and point of no return (PNR) calculations essential for diversion planning.

Great circle route: shortest distance between two points; initial and final true tracks differ; use gnomonic chart or flight planner.

Rhumb line: constant true track; longer than great circle except at equator or meridian.

Grid navigation: uses grid north; used in polar regions where magnetic compass unreliable; grid track = true track ± convergence.

Inertial navigation systems (INS/IRS): self-contained; position drift ~1 NM/hr; align before flight.

Required navigation performance (RNP) for oceanic: RNP 10 (RNAV 10) or RNP 4; RNP 4 requires GNSS or INS.

Air data computer (ADC): computes altitude, airspeed, Mach, temperature from pitot-static and temperature probes.

Inertial reference system (IRS): ring laser gyros or accelerometers; provides attitude, heading, position, velocity; drift with time.

Flight management system (FMS): integrates navigation sensors, performance database, flight plan; computes LNAV/VNAV guidance.

Electronic flight instrument system (EFIS): displays primary flight display (PFD) and navigation display (ND); shows route, weather, terrain.

Traffic alert and collision avoidance system (TCAS): interrogates transponders; resolution advisory (RA) and traffic advisory (TA).

Ground proximity warning system (GPWS): alerts on excessive descent rate, terrain closure, altitude loss; enhanced GPWS (EGPWS) uses terrain database.

Distance measuring equipment (DME): measures slant range; paired with VOR or ILS; accuracy ±0.5 NM.

Automatic direction finder (ADF): senses relative bearing to NDB; magnetic bearing = heading + relative bearing; errors from thunderstorm, terrain.