Chapter 6 - Navigation

This chapter is an expanded exam-and-flight-practice reference for PPL navigation. It combines core theory, formula memory aids, worked examples, and cockpit decision flow.

How to use this chapter

Study habits: Every formula should pair with a sketched wind triangle or chart line. Timed practice: one full DR leg from memory weekly.

6.1 Earth Geometry and Direction Basics

Why this matters

Navigation starts with a geometric model of Earth. Most exam mistakes here come from mixing latitude distance rules with longitude rules.

Core concepts

• Great Circle (GC): shortest path between two points on a sphere.
• Rhumb Line (RL/Loxodrome): crosses all meridians at a constant angle (constant track).
• Meridians: lines from pole to pole (longitude).
• Parallels: east-west circles (latitude), only equator is a great circle.

Graphic: GC vs RL concept

flowchart LR
    A(Point A) -->|Great Circle: shortest| B(Point B)
    A -->|Rhumb Line: constant heading| B

Key constants

6.2 Latitude, Longitude, and Distance Calculations

Latitude distance

or in minutes:

Longitude distance (Departure)

Where:

• $\Delta \lambda$ is longitude difference in minutes.
• Mean latitude is used for the segment.

Worked example

• $\Delta \lambda = 30^\circ 12’ = 1812’$
• Mean Lat $= 37^\circ$
• Departure $= 1812 \times \cos 37^\circ \approx 1447$ NM

Exam trap

• Forgetting the cosine factor in departure formula is one of the most common errors.

6.3 Time Discipline (UTC, ETA, ETO)

• Plan and report in UTC.
• Recompute ETA/ETO whenever actual groundspeed differs from planned.
• In SAR context, precise reporting time matters as much as position.

Quick formulas

6.4 Dead Reckoning, Wind Triangle, Tracks, and Headings

Real-world application

GNSS gives position; DR gives understanding when the screen fails — exams reward a labelled wind triangle more than calculator memory.

Ask yourself: Track made good differs from planned track — is your 1-in-60 correction based on distance flown or to go, as the question states?

Dead reckoning (DR)

Definition — dead reckoning: navigation from a known position using heading, time, and speed (and wind correction) to estimate a new position.

DR loop (each leg)

1. Mark position and time at fix.
2. Determine true track on chart to next checkpoint.
3. Solve wind triangle → true heading and groundspeed.
4. Convert TH → MH → CH (variation/deviation).
5. Fly heading; note time overhead checkpoint.
6. Compare actual position to planned — apply 1-in-60 if off track (§6.7).

Definitions (wind triangle)

• Track (TRK/TT): intended or actual path over the ground.
• Heading (HDG/TH/MH/CH): direction the aircraft nose points (true, magnetic, or compass).
• Drift: lateral displacement from wind; drift angle is heading–track difference.
• WCA (wind correction angle): angle applied into wind to hold planned track.
• TAS: speed through the air. GS: speed over the ground (wind triangle resultant).

Graphic: wind triangle logic

flowchart TD
    W[Wind vector] --> R[Resultant: track and GS]
    A[TAS on heading vector] --> R
    R --> GS[Groundspeed]
    R --> TRK[Track made good]

Memory: three vectors — wind, TAS/heading, ground track/GS — close the triangle.

Step-by-step wind triangle + DR (worked example)

Given (leg briefing data)

Step 1 — True heading (TH)

• Wind from the left → correct left (north side of eastbound track).
• TH = TT − WCA = 090° − 11° = **079°T**

Step 2 — Magnetic and compass headings

• East variation (12°E): MH = TH − variation = 079° − 12° = **067°M**
• Deviation −3°: CH = MH − deviation = 067° − (−3°) = **070°C**

Step 3 — Groundspeed (GS)

• With ~20 kt crosswind on 100 kt TAS, computer/plot GS ≈ 98 kt (small reduction from pure crosswind case).
• Always take GS from E6B / approved plot, not guess, in real flight.

Step 4 — Time en route (ETE) and ETA

ETE (hr) = Distance / GS = 60 / 98 ≈ 0.61 hr ≈ 37 minutes

• If departure fix at 0300 UTC, ETA next checkpoint ≈ 0337 UTC.

Step 5 — DR position check

• After 37 min on heading 070°C, you should be near checkpoint (allowing for minor wind change).
• If landmark early/late → revise GS and ETA for next leg (§6.13).

Step 6 — If off track in flight

• At halfway (30 NM), you are 2 NM right of track.
• Track error ≈ 2 × 60 / 30 = 4° → adjust heading 4° left into error (§6.7).

Sign reminders

• Wind from right → correct right (add WCA to TH in typical notation).
• Wind from left → correct left.
• Never confuse wind direction (FROM) with track (direction of travel over ground).

CASA Exam Cues — DR and wind triangle

• Exam expects order: TT → WCA → TH → MH → CH → GS → ETE.
• Wind is almost always given as direction wind is FROM.
• GS for time calculation, not TAS, unless question asks airborne time only.
• Show variation/deviation steps separately — easy marks lost on sign.

6.5 Compass, Variation, and Deviation

Types of north

Conversion chain

Memory aid: True Virgins Make Dull Company.

Worked conversion

• $CH = 345^\circ$
• Deviation $= -7^\circ$ (west)
• $MH = 338^\circ$
• Variation $= +27^\circ$ (west)
• $TH = 005^\circ$

6.6 Earth Convergence and Conversion Angle

Earth convergence

Where:

• $Cv$ = angle between meridians over longitude interval.
• $\Delta \lambda$ in degrees.

Conversion angle (commonly used with Lambert assumptions)

RL from GC relationship

Worked example

• $\Delta \lambda = 90^\circ,\; \text{Mean Lat}=45^\circ$
• $Cv = 90 \times \sin 45^\circ \approx 64^\circ$
• $CA \approx 32^\circ$

6.7 1-in-60 Rule and Track Error Correction

Formula set

Fast mental anchor

• 1 NM off after 60 NM flown ~= 1 deg error.

Worked example

• 4 NM right of track after 80 NM flown:
  • Track error $= 4 \times 60 / 80 = 3^\circ$
• 40 NM to destination:
  • Closing angle $= 4 \times 60 / 40 = 6^\circ$
• Total correction left $= 9^\circ$

6.8 Wind Components and Runway Use

Given angle $\theta$ between runway heading and wind direction:

Clock code estimates

Operational reminders

• Crosswind and tailwind must be checked against aircraft/operation limits.
• Headwind usually improves takeoff/landing performance but still verify distance data.

6.9 Chart Projections (Exam Focus)

Mercator

• Conformal (angles preserved locally).
• Rhumb lines plot as straight lines.
• Scale distortion increases with latitude.

Lambert Conformal Conic

• Standard aviation enroute chart projection.
• Good compromise over mid-latitudes.
• GC and RL can both appear nearly straight over moderate ranges.

Polar stereographic

• Used for high latitudes.
• Useful where meridian convergence is extreme.

Comparison table

6.10 Grid Navigation and Grivation (Advanced awareness)

At high latitudes, true/magnetic references become difficult due to meridian convergence and magnetic behavior. Grid references provide a stable operational framework.

• Grid Convergence: difference between Grid North and True North.
• Grivation: difference between Grid North and Magnetic North.

Use these terms for conceptual exam questions, even if not heavily used in basic PPL route flying.

6.11 Radio Navigation Essentials (PPL level)

NDB/ADF

• ADF needle indicates relative bearing to station.
• Convert relative bearing to QDM/QDR style understanding with heading context.
• Errors: night effect, coastal refraction, thunderstorms, mountainous terrain.

VOR

• Radials are from the station.
• Correct TO/FROM interpretation is critical.
• Tracking and intercept logic should be practiced, not memorized only.

DME

• Reads slant range, not always horizontal distance.
• Largest slant-range error when high and near station.

6.12 GNSS/GPS Practical Use and Risk Management

Definition — GNSS: Global Navigation Satellite System (e.g. GPS, GLONASS, Galileo) used for position, track, and time.

Core operating points

• Verify active flight plan, waypoint sequence, and active leg.
• Check CDI scale/sensitivity and mode (ENR vs APR).
• Cross-check against chart, DR, and terrain — one source is not enough.

RAIM (Receiver Autonomous Integrity Monitoring)

Definition — RAIM: function in many IFR-approved GPS receivers that checks consistency between satellites to detect faulty information; integrity may be unavailable if insufficient satellites or geometry.

SBAS and LPV (Australia context)

Definition — SBAS (Satellite Based Augmentation System): broadcasts corrections via geostationary satellites to improve accuracy and provide integrity (e.g. WAAS USA, EGNOS Europe; Australia has pursued Southern Positioning Augmentation Network (SouthPAN) for regional SBAS capability — confirm current status in briefing material).

• PPL VFR: you may not fly LPV approaches without appropriate rating/aircraft approval — exam may test concept only.

GNSS limitations (operational and exam)

flowchart TD
    G[GNSS primary display] --> C{Matches chart and DR?}
    C -- Yes --> OK[Continue and monitor]
    C -- No --> F[Fix error or stop using until resolved]

Pilot discipline

• GNSS is a primary situational aid, not single-source truth.
• Continue map / terrain / time cross-check (pilotage + DR).

• Confirm database currency and NOTAM (GPS outages, RAIM) before flight.

• CASA — GNSS and navigation safety context
• FAA PHAK — navigation systems

6.13 Navigation Log and In-Flight Replanning

Minimum useful nav log fields

In-flight update loop

flowchart LR
    A[Checkpoint time] --> B[Recompute GS]
    B --> C[Update ETA and fuel]
    C --> D{Trend acceptable?}
    D -- Yes --> E[Continue and monitor]
    D -- No --> F[Divert early]

6.14 Lost Procedure and Repositioning

Priority order (always)

1. Aviate — safe altitude, terrain clearance, stable aircraft control.
2. Navigate — establish position (GNSS, pilotage, radio aids, DR back-check).
3. Communicate — ATS/FIS/CTAF; do not delay while guessing position.

Same hierarchy as emergency radio work: Aviate, Navigate, Communicate (Chapter 7).

Typical practical sequence

flowchart TD
    L[Uncertain of position] --> A[Aviate safe altitude]
    A --> N[Fix position if possible]
    N --> C[Communicate position request to ATS/FIS]
    C --> D{Resolved?}
    D -- Yes --> R[Resume or divert as needed]
    D -- No --> E[Land when safe / declare urgency]

Link to Air Law — SAR and flight notification

Getting lost is not automatically a distress event, but it can become one if fuel, weather, or terrain margins erode. Your legal and SAR context matters:

Operational SAR-minded habits

• Lodge realistic SARTIME with margin; update or cancel after diversion.
• If lost and past planned ETA: call ATS/FIS early — you are not “bothering” them; you are activating the safety system.
• Provide: callsign, last known position, heading, altitude, endurance, persons on board, intentions.
• If you land at non-planned aerodrome: cancel SARTIME and notify someone expecting you.

Exam scenario pattern: pilot lost, fuel adequate, VMC — correct answer includes maintain control, fix position, communicate for help, and awareness of SARTIME/notification obligations — not silent continued wandering.

• Airservices — SARTIME
• CASA — flight plans and SARTIME

6.15 Human Factors and Error Management

Common traps:

• Confirmation bias (“I must be here”).
• Fixation on one source (e.g., GNSS only).
• Late correction due to poor time discipline.

Countermeasures:

• Use time-track-distance triangle every leg.
• Run periodic gross-error checks.
• Brief diversion gates before departure.

6.16 Formula Pack (Quick Revision)

6.17 Pre-Exam Revision (Must Know · Nice to Know · Common Traps)

Sketch it: Wind triangle with W FROM 270; chart track with 1-in-60 correction; compass rose with variation east/west.

Must know

• DR leg: TT, WCA, TH, MH, CH; GS for ETE/ETA (not TAS unless question says so).
• Wind triangle: wind FROM direction; plot correctly.
• Chart measure: NM, variation, drift; 1-in-60 track error.
• Lost procedure: climb, conserve, navigate, communicate; SARTIME (Ch 1).
• GNSS limitations: RAIM, database currency, cross-check with map.

Nice to know

• E6-B / flight computer shortcuts; conversion angle on long legs.
• ETP/PNR at PPL level if in workbook.
• Great circle vs rhumb line concept.

Common traps

• True/magnetic/compass mixed in one chain without conversion table.
• Wrong variation sign (east/west).
• TAS instead of GS for time.
• Wind FROM vs TO when plotting.
• Cosine forgotten in longitude distance.
• 1-in-60 with wrong distance (flown vs to-go).
• GNSS trusted without map check.
• Lost answer omits communicate or SARTIME cancel.

Study plan (high retention)

1. Write formula pack from memory daily.
2. Mixed 10-question blocks: wind, conversion, chart, timing.
3. Explain each result (“why this sign?”).
4. One full DR leg weekly under time pressure.
5. Tidy wind-triangle sketch every session.

References

CASA Primary / Australian operational

• CASA Visual Navigation Guide and VFR resources: https://www.casa.gov.au/
• Airservices SARTIME: https://www.airservicesaustralia.com/industry-info/pilot-tools/sartime/
• CASA RPL/PPL/CPL Aeroplane Workbook: https://www.casa.gov.au/rpl-ppl-and-cpl-aeroplane-workbook

PHAK Secondary / supplementary

• FAA PHAK (Navigation chapters): https://www.faa.gov/regulations_policies/handbooks_manuals/aviation/phak
• ICAO Annex 4 (Aeronautical Charts): https://www.icao.int/
• EASA ATPL Learning Objectives (General Navigation): https://www.easa.europa.eu/

IMPORTANT: Always verify with current official publications.