Learn dead reckoning navigation in a flight simulator: plan wind-corrected headings and times, fly checkpoints, and correct common errors.
To use dead reckoning in a flight simulator, start from a known position, calculate each leg's heading, groundspeed and time from course, distance and wind, then fly those numbers while timing the leg. Compare your predicted position with checkpoints, correct the next heading, and update the navigation log.
In aviation and real-world flying, dead reckoning (DR) predicts position without continuous external position information. Visual landmarks provide independent fixes through pilotage; combining the two is the practical method used on most VFR exercises. Our guide to checkpoint selection and basic visual navigation covers that supporting skill.
How do you plan a dead reckoning route?
Plan the route as short, timed legs with a heading, expected groundspeed and recognisable checkpoint for each one.
- Choose a known starting point. Use a runway departure end, an overhead airport position or an unmistakable landmark. Avoid starting the clock at an arbitrary point during the climb.
- Measure the true course. Draw each leg on the chart and measure its direction against true north. Keep course separate from heading: course is the intended path over the ground, while heading is where the aircraft's nose points. Our explanation of course, heading, bearing and track clarifies the terms.
- Apply the wind. Use the forecast wind at cruising altitude and the aircraft's true airspeed to calculate wind-correction angle and groundspeed. Aviation winds are described by the direction they come from. Confirm whether the simulator's weather display uses true or magnetic direction rather than assuming.
- Convert true heading to magnetic. When converting manually, subtract easterly variation and add westerly variation. Do not apply variation twice if the planner or cockpit display already gives magnetic headings. Compass deviation may also matter in aircraft that model it.
- Calculate time and fuel. Use
time in minutes = distance in NM ÷ groundspeed in knots × 60. Fuel for the leg is planned fuel flow multiplied by time in hours. Record both leg and cumulative times in a navigation log. - Configure the exercise. Set the planned weather, use normal simulation rate, and hide the moving map, route line, aircraft labels and GPS position. Keep a clock or stopwatch visible. Live or changing weather can legitimately make the original figures inaccurate.
Choose checkpoints that are distinctive in the simulator's scenery: airports, coastlines, large lakes, major road junctions and prominent towns usually work better than individual buildings. Old or simplified scenery may not match a modern chart, so favour large, stable features.
How do you fly each dead reckoning leg?
Cross the starting fix, start the timer, establish the planned heading and airspeed, then hold them until the calculated arrival time.
- Start at the fix. Begin timing as the aircraft crosses or passes abeam the nominated point, not after completing the turn.
- Stabilise the aircraft. Set the planned power, altitude, airspeed and magnetic heading. Use the directional indicator rather than chasing a magnetic compass while it is disturbed by a turn.
- Maintain the numbers. Small heading and speed errors accumulate. Scan outside for the checkpoint, but do not weave around searching for it.
- Record the result. Note the actual arrival time and which side of the planned track the checkpoint appeared. Start the next leg's timer at its nominated fix and revise later estimates when necessary.
Heading-hold autopilot is reasonable when the exercise is testing navigation calculations rather than hand-flying accuracy. Do not use NAV or LNAV mode, because that follows the programmed route instead of testing dead reckoning.
FSX users can practise the method with an Acceleration mission built around dead reckoning before progressing to an instrument approach.
How do you correct a dead reckoning error?
Correct lateral displacement with a track and closing-angle calculation; correct an early or late arrival by revising groundspeed and time rather than changing heading.
The one-in-60 rule is accurate enough for small angles: track error ≈ 60 × lateral error ÷ distance flown. To regain the route, add closing angle ≈ 60 × lateral error ÷ distance remaining.
For example, being 2 NM right of track after flying 20 NM indicates roughly 6° of right track error. With 30 NM remaining, another 4° left will close the 2 NM displacement, so initially fly about 10° left of the original heading. Once back on track, remove the 4° closing angle. Retain the 6° drift correction only if steady wind or a planning error caused the displacement; after a temporary handling error, return to the original planned heading.
If the aircraft is on track but arrives early, the groundspeed was higher than planned. Calculate actual groundspeed = distance flown ÷ elapsed hours and revise subsequent estimates. A mistake we see constantly is altering heading when only the arrival time is wrong.
Why does dead reckoning go wrong in a simulator?
Most large errors come from mixing reference systems, using the wrong speed or mishandling the timer rather than from the basic method itself.
| Symptom | Likely cause | Correction |
|---|---|---|
| Every checkpoint is on the same side | Wrong wind correction, wind interpreted as blowing towards rather than from, or a steering bias | Use a confirmed fix and apply the one-in-60 correction |
| Checkpoint is on track but early or late | Incorrect groundspeed, true airspeed or wind estimate | Recalculate actual groundspeed and revise times; leave heading alone |
| Route has a large fixed angular error | True and magnetic headings mixed, or variation applied twice | Audit every course-to-heading conversion |
| Error begins after each turn | Timer started after rolling out instead of at the turning point | Time from the fix and account for the turn in the plan |
| No recognisable feature appears | Poor checkpoint, reduced visibility or chart and scenery differences | Use a larger feature and re-establish position instead of wandering off heading |
| Heading continually oscillates | Chasing the compass or making corrections too frequently | Let the instruments settle and use small, deliberate corrections |
Can you use dead reckoning without visual checkpoints?
Yes, but positional uncertainty grows continuously when there is no landmark or electronic fix to confirm the estimate.
Featureless terrain, open water, darkness and cloud expose every error in wind, heading, speed and timing. In a simulator, this makes a useful advanced exercise: keep the GPS hidden during the flight, then compare its recorded or displayed position with the navigation log afterwards.
In real-world flying, dead reckoning is a planning and backup skill, not a reason to ignore approved equipment, weather limitations or airspace requirements. If the estimated position becomes doubtful, use an available radio or satellite fix and communicate as required; our comparison of GPS and radio navigation methods explains when each is useful in a simulator.