How do you set up aircraft performance in Little Navmap?

To set up aircraft performance in Little Navmap, create or load a separate performance profile for the exact aircraft variant, enter realistic climb, cruise and descent speeds, rates and fuel flows, add taxi and reserve fuel assumptions, save the profile, then recalculate the flight plan and verify the results against a known flight.

This is a general Little Navmap procedure used with MSFS, X-Plane, Prepar3D and FSX. The performance profile is separate from the simulator aircraft, so changing aircraft does not always select the correct profile automatically. If the map, simulator connection or route tools are unfamiliar, start with our basic Little Navmap connection and flight-planning workflow.

Which aircraft performance values should you enter?

Little Navmap needs representative values for each phase of flight rather than every figure from the aircraft manual. Its profile is an averaged planning model, not a full performance computer that accounts for every weight, altitude and power-setting combination.

Use the units printed beside each field. Cruise speed is normally entered as true airspeed, while climb and descent fields must follow the speed type shown by the editor. For a multi-engine aircraft, fuel flow means the combined flow from all engines.

The best manual source is the aircraft's operating handbook or add-on documentation. Our explanation of turning aircraft performance charts into planning values covers how to choose representative figures without mixing incompatible weights, temperatures and altitudes.

How do you create and activate the profile?

1. Open the Aircraft Performance editor. Find it in Little Navmap's aircraft-related menu or performance panel. Command wording can differ slightly between releases.
2. Create or load a profile. Start a new profile for manual entry, or load an existing .lnmperf file if one matches the exact aircraft and engine variant.
3. Set the aircraft and fuel details first. Select the correct fuel type and units before copying fuel-flow or capacity figures.
4. Enter climb, cruise and descent averages. Use normal operating figures, not maximum published performance. For cruise, choose values appropriate to the altitude and power setting used in most of your plans.
5. Set fuel allowances separately. Add taxi and reserve assumptions through the available profile or fuel-planning controls rather than inflating cruise consumption.
6. Save the profile with a clear name. Include the aircraft variant and operating style, such as economy or high-speed cruise. Confirm that this profile is shown as loaded or active.
7. Recalculate and inspect the route. Check estimated flight time, top of climb, top of descent, trip fuel, reserve and destination fuel. Implausible values usually reveal a unit or speed-type error.

Can Little Navmap collect performance automatically?

Little Navmap can derive performance from a connected simulator, which is often the better choice for add-on aircraft whose simulated behaviour differs from published figures. The aircraft must report usable speed and fuel-flow data for collection to work.

1. Prepare a representative flight. Use a normal payload, sensible fuel load and the cruise altitude and power setting you usually fly.
2. Enable performance collection. Use the collection control in the Aircraft Performance area, then fly normal climb, level cruise and descent segments.
3. Keep each segment stable. Avoid repeated level-offs, unusual power changes, pausing, teleporting and time acceleration. Allow enough steady cruise time for a useful average.
4. Review before merging or saving. Reject obviously corrupted figures, then save the collected data as a new profile instead of overwriting a reliable baseline immediately.

If an aircraft reports zero, intermittent or unrealistic fuel flow to Little Navmap, automatic collection will reproduce that bad telemetry. Enter manual values instead and calibrate them from fuel used over a timed, stable segment.

Why are Little Navmap fuel or flight-time estimates wrong?

Large errors usually come from the profile, its units or the active weather data rather than the route itself.

• Fuel burn is roughly half the expected value: fuel flow for one engine was probably entered for a twin-engine aircraft.
• Flight time is much too short: indicated airspeed or ground speed may have been entered where true airspeed was required.
• Fuel figures are wildly high or low: check pounds, kilograms, US gallons, litres and the selected fuel type.
• The estimate belongs to another aircraft: verify the loaded profile after changing aircraft or simulator add-ons.
• Only one phase is inaccurate: adjust that phase rather than changing every value. For example, correct cruise fuel flow without altering climb performance.
• Eastbound and westbound times differ sharply: winds aloft are affecting ground speed. Do not encode a headwind into the profile's cruise speed; read how wind, temperature and density altitude affect aircraft performance instead.
• A jet is accurate at one altitude but not another: a single averaged profile cannot reproduce every combination of weight, flight level and cost index.

Calibrate one phase at a time. If stable cruise burns 10 percent more fuel than Little Navmap predicts under the same conditions, increase the cruise fuel-flow value by about 10 percent, save the profile under a revised name and test again.

Do you need a separate profile for every aircraft?

Create separate profiles whenever engine type, performance, fuel capacity or normal operating technique changes materially. Different liveries of the same aircraft normally share a profile, but a piston and turboprop conversion, alternative engine option or heavily modified add-on should not.

For aircraft with a wide operating range, separate economy, high-speed, low-altitude or high-altitude profiles can produce better estimates than forcing one average to cover every mission. Use descriptive names and confirm the active profile before calculating fuel.