Commercial pilot · ACS CA.VI.A
Pilotage and Dead Reckoning
A commercial pilot navigates by plan and confirms by sight: a flight log built on wind-corrected headings and real groundspeeds, checked against landmarks, with corrections made early.
Why this one matters
Most navigation accidents aren't about being slightly off course: they're about running out of fuel, flying into terrain or weather while unsure of position, or a GPS failure the pilot couldn't back up. Pilotage and dead reckoning are the backup that always works, and the habit of comparing plan to actual catches a problem while there are still options.
Can’t miss
- •Pilotage is navigating by visible landmarks; dead reckoning is navigating by computed heading, groundspeed and time. Use them together and cross-check.(PHAK (FAA-H-8083-25C), Navigation)
- •From true course: apply wind correction to get true heading, variation to get magnetic heading ("east is least, west is best"), deviation to get compass heading.(PHAK (FAA-H-8083-25C), Navigation)
- •True airspeed is higher than indicated as altitude rises (roughly 2% per 1,000 feet); plan with TAS from the POH for the altitude and temperature.(PHAK (FAA-H-8083-25C), Navigation)
- •Compass errors in the northern hemisphere: turning errors, greatest on north and south headings (undershoot north, overshoot south), and acceleration errors on east and west headings only (accelerate north, decelerate south). Read it only in steady, unaccelerated flight.(PHAK (FAA-H-8083-25C), Flight Instruments (magnetic compass))
- •Keep a flight log: actual times over checkpoints, revised groundspeed and ETA, and fuel against plan. Revise early.(PHAK (FAA-H-8083-25C), Navigation)
- •Commercial standard: within 2 nm of the planned route, checkpoints within 3 minutes of the ETA, altitude ±100 feet, heading ±10°.(Commercial Pilot ACS (FAA-S-ACS-7B), CA.VI.A.S5-S7)
- •Watch fuel against the plan; VFR reserve is 30 minutes by day and 45 at night, and a commercial pilot plans more than the minimum.(14 CFR 91.151)
What you should know
The plan K1 · K3 · K4
- Choose a route that avoids terrain, airspace and long stretches without landing options; choose altitudes for terrain clearance, winds and cloud clearance. More than 3,000 feet above the surface, the hemispheric rule: magnetic course 0-179°, odd thousands plus 500 MSL (3,500, 5,500); 180-359°, even thousands plus 500 (4,500, 6,500), unless ATC assigns otherwise.(PHAK (FAA-H-8083-25C), Navigation; 14 CFR 91.159)
- Pick checkpoints that are unmistakable from the air: a river bend, a highway interchange, a lake, a town with a distinctive shape. Space them about every 10 to 15 minutes.(PHAK (FAA-H-8083-25C), Navigation)
- Read the topography on the chart: contour shading, maximum elevation figures, towers and obstacles near your route.(PHAK (FAA-H-8083-25C), Navigation)
Plotting it K5 · K6
- Measure the true course, apply the wind correction angle from the forecast winds, then variation and deviation to get the compass heading.(PHAK (FAA-H-8083-25C), Navigation)
- Compute groundspeed, time and fuel for each leg with your E6B or app; use TAS for the planned altitude and temperature (density altitude raises TAS for the same indicated speed).(PHAK (FAA-H-8083-25C), Navigation)
- Set power and mixture by the POH for the planned cruise; the fuel burn in the plan only holds if you fly that power setting.(PHAK (FAA-H-8083-25C), Navigation)
Plan versus actual K2 · K7 · R3
- At each checkpoint, note the time; compare with the plan to get the real groundspeed and a revised ETA and fuel figure.(PHAK (FAA-H-8083-25C), Navigation)
- Drift, by the 1-in-60 rule: each nm off course per 60 nm flown is about 1° of drift. To parallel the course, add the drift angle; to reach the destination, add the drift angle plus a closing angle (distance off per 60 nm remaining). Hold the original wind correction plus that total. Small, early corrections beat large late ones.(PHAK (FAA-H-8083-25C), Navigation)
- Turns to headings on the compass, northern hemisphere: turning toward north the card leads (shows the turn too soon), so stop the turn early, by 15° plus half your latitude (about 35° at 40° N); turning toward south it lags, so let it pass south by the same amount before rolling out. Read it only in steady, unaccelerated flight.(PHAK (FAA-H-8083-25C), Flight Instruments (magnetic compass))
- Fuel burning faster than planned (headwinds, wrong mixture, a leak): recompute the reserve and divert early rather than late.(14 CFR 91.151; RMH)
Eyes outside R1 · R2
- Navigation pulls your eyes to the chart and the log: keep scanning in short sections, and use flight following.(AC 90-48, Pilots' Role in Collision Avoidance)
- Prioritize: aviate (altitude, heading), navigate (where am I), communicate. A wrong landmark identification often comes from forcing the ground to fit the chart.(Risk Management Handbook (FAA-H-8083-2A))
On the flight
ACS standards
- Prepare and use a flight log; navigate by pilotage and by computed headings, groundspeeds and elapsed time; use the magnetic compass for turns to headings.(Commercial Pilot ACS (FAA-S-ACS-7B), CA.VI.A.S1-S4)
- Within 2 nm of the planned route; checkpoints within 3 minutes of the ETA, with a destination estimate; altitude ±100 feet, heading ±10°.(Commercial Pilot ACS (FAA-S-ACS-7B), CA.VI.A.S5-S7)
What your instructor is watching for
Your instructor watches for a usable flight log, wind-corrected headings, checkpoint times recorded and ETAs revised, early course corrections, compass turns flown correctly, and altitude and heading within commercial tolerances.
Scenarios
Decide what you would do first, then see the worked answer.
With the heading indicator failed, you turn right from 270 toward north using only the magnetic compass.
When do you roll out? See the worked answer
Before the compass reads north: in the northern hemisphere, turning toward north the card leads, showing a false northerly reading, so roll out early: 15° plus half the latitude (about 35° early at 40° N). Roll out early (roughly by your latitude in degrees), then confirm in steady, level flight and correct.
PHAK (FAA-H-8083-25C), Flight Instruments (magnetic compass)
Your checkpoint should be a town with a racetrack, but you see two towns.
How do you decide? See the worked answer
Check the time and heading: which one fits your dead-reckoning position? Then look for a second feature that matches only one of them. Don't make the ground fit the chart.
PHAK (FAA-H-8083-25C), Navigation
The winds aloft were wrong: you're drifting 3 nm right of course after 20 minutes.
How do you correct? See the worked answer
3 nm off after 20 minutes at, say, 120 knots (40 nm flown) is about 4.5° of drift. To return over the next 40 nm, turn about 9° left (4.5° drift plus 4.5° closing), then hold the old correction plus 4.5°; update the groundspeed and ETA.
PHAK (FAA-H-8083-25C), Navigation
Common mistakes
Not recording checkpoint times.
Without them there's no real groundspeed and no good lost-procedure starting point.
Instead: Write the time at every checkpoint.
Reading the compass in a turn.
Turning and acceleration errors make it wrong.
Instead: Use the heading indicator in turns; read the compass in steady flight.
Planning with indicated, not true, airspeed.
Groundspeed and times come out wrong at altitude.
Instead: Plan with TAS for the altitude and temperature.
Now train it
Say it out loud, hear it asked, and take the quick check in this lesson’s practice pack. It tracks your shaky spots.
Got it?
When it feels solid, practice pilotage and dead reckoning out loud with our examiner.
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Teaching this? The instructor lesson plan →
Sources
- Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C): Navigation; Flight Instruments
- Advanced Avionics Handbook (FAA-H-8083-6)
- Aeronautical Information Manual (AIM): Chapters 1, 4, 6 and 7
- 14 CFR Part 91: 91.3, 91.103, 91.123, 91.151, 91.171, 91.215, 91.225
- AC 90-48 and AC 91-78
- Commercial Pilot ACS (FAA-S-ACS-7B): Area VI
Study aid, not FAA guidance. Regulations change; check the current text at eCFR and the ACS. Checked against current sources 2026-11-13.