Takeoff & Landing Performance FAQs

Q: I’m not seeing the Takeoff and Landing button on Flights page. Why?

A: Runway performance calculation requires a subscription to the Performance Plus tier, as well as use of an aircraft for which a runway performance model exists. View the list of supported aircraft models at the bottom of the page to see if we support your aircraft.

Q: How do I know if my aircraft is supported for runway performance calculations?

A: View the list of supported aircraft models at the bottom of the page, or search our Performance Directory for your aircraft. Any aircraft with a blue line stating “Supports Takeoff & Landing Performance”, then your aircraft has been modeled and will provide takeoff/landing performance calculations.

Q: Why can’t I change my takeoff/landing weight on the runway performance page?

A: The takeoff/landing weight is directly tied to the takeoff/landing weight on Flights page; if the presented takeoff/landing weight on the runway performance page is not what you desire to use for calculations, you will need to modify your payload and/or fuel load on Flights first, to achieve the desired takeoff/landing weight for runway performance calculations.

Q: I’m changing my takeoff/landing weight, but the distance results do not change. Why is that?

A: Consult your POH. It is likely that takeoff and/or landing performance data are only published for a single takeoff or landing weight, specifically that maximum takeoff or landing weight for your aircraft. If that is the case, you will always see results for the maximum takeoff or landing weight, regardless of your actual takeoff/landing weight.

Q: Runway slope does not seem to affect distance results.

A: Consult your POH. Many aircraft do not publish runway slope effect on takeoff and landing performance. If that is the case, runway slope changes will not be reflected in the calculated distance results.

Q: Why am I seeing “runway slope of 3% exceeds published limit of 2%” message?

A: Most aircraft POH do not include runway slope effects on takeoff/landing distance. For those POH which do include this effect, the published slope range is a hard limit. Typically slope effects of +2% uphill through -2% downhill are published. Any runway slope outside of that range is unknown and cannot be used for calculation. Consult your POH for more information around the slope limits for your aircraft.

Q: Why am I seeing an “Outside air temperature out of range”message?

A: Consult your POH. The provided input Temperature likely exceeds what is published for that pressure altitude.

Q: Why am I seeing a “Tailwind component out of range” message?

A: Most aircraft are limited to a maximum of 10 knot tailwind component. Some aircraft have a 5 knot limit. When the tailwind component exceeds this limit, you will see this message because takeoff/landing with this tailwind component is not allowed. Consult your POH for full details on the limits of your aircraft.

Q: I’m not seeing any calculation result differences when changing from 31 knot to 36 knot headwind. Why?

A: Most aircraft manufacturers publish wind effect on takeoff/landing performance up to 30 knots headwind component (some publish to 15 knots). For winds greater than the published maximum headwind component, the maximum published headwind component is used, as a greater headwind component results in an even shorter, and therefore more conservative, takeoff/landing distance.

Q: Changing wind has no effect on my takeoff/landing distances.

A: Consult your POH. It is likely that the takeoff/landing performance data does not include a wind effect at all.

Q: Why can’t I change the runway surface to grass for my aircraft?

A: Consult your POH. Some (but few) aircraft POHs publish non-paved runway corrections. If your aircraft’s POH includes them, you will see a Runway Surface selection in the Runway group on the takeoff/landing page.

Q: If I select a grass runway in the runway picker, and my aircraft’s POH support grass runway corrections, why isn’t the Runway Surface selector automatically set to Grass Runway?

A: Automatic selection of runway surface type based on the runway selected is currently not supported. Grass runways can be tricky, as some aircraft manufacturers simply use “Grass Runway” while others use “Dry Grass” and “Wet Grass” and yet others have 3-4 different grass depths. For this reason it’s up to the pilot to manually make the best selection for their runway condition.

Q: Is density altitude considered in these performance calculations?

A: Yes. Density altitude is pressure altitude corrected for temperature effects. Most POH performance data operate with pressure altitude and outside air temperature inputs, which together, factor into a density altitude.

Q: Why can’t I directly change my altitude input on the takeoff/landing page?

A: Because performance calculations are based on pressure altitude, pressure altitude is automatically calculated from the aircraft’s elevation and the METAR or manually provided altimeter setting.

Q: I’m changing cold temperature (or light weight) inputs, but my performance results are not changing. Why?

A: Consult your POH for the low-end temperature and weight limits. For inputs less than those limits, performance results are calculated at the published low weight (or temperature) limit. The results provided are more conservative (longer distance, lower rate-of-climb, etc) than if calculated with your actual inputs.

Q: Why am I not seeing any results when I provide a set of inputs?

A: Consult your POH, specifically checking for the allowable aircraft configuration. Some aircraft require a specific flap setting when other conditions (such as icing) exist. If a non-allowed flap setting is chosen, no results are displayed, as this flight condition is not allowed, per POH.

Q: I picked my aircraft, it supports Runway Performance, I tapped on the Takeoff button and see a list of serial number ranges for my aircraft - what do I do? Which one do I pick?

A: Consult your POH and your aircraft registration information. Some aircraft have differing runway performance data for multiple serial number ranges within the total production run. In other words, as the aircraft production continued over many years, improvements were made, which affect runway performance. Find the serial number for your aircraft and pick the option within which your serial number falls. If your range is not provided, please contact us at team@foreflight.com to provide details on your aircraft (POH, serial number) so we can research your specific case.

Q: Are runway performance data synced between FF Mobile and FF Web?

A: Yes

Q: When connected to ADS-B, or any other in-flight weather source, will METAR data be used to prefill runway performance page weather for an airport with METAR coverage?

A: Yes.