ForeFlight recently began offering takeoff and landing performance information in their application.
The app pulls information from current METARs at your departing and arriving airports and it calculates your takeoff and landing speeds and distances
based on the weight and fuel loading you add. ForeFlight is careful to advise us that the numbers come from the pilot operating handbook values
and we all know those tend to be a little optimistic.
So the Air Safety Institute decided to run a small test with two common airplanes a Beechcraft Bonanza and a Cessna 182
to find out just how accurate are these calculations that we can now so easily see in ForeFlight.
First a Cessna 182.
Richard your ground roll should be, uh, 433 feet.
Okay. Thanks.
I flew the 182 and based on the weight and fuel that I entered and the METAR information that ForeFlight
calculated we expected a take-off distance of 433 feet.
In reality as you can see the 182 leaves the runway at about 600 feet. Roughly thirty percent beyond the
433 feet calculated in ForeFlight.
Mike Juliet we're expecting a 587 foot ground roll on this one.
For landing ForeFlight calculated a stopping distance of
587 feet with maximum braking.
Now I don't come to a complete stop because I'm on an active runway and I don't want to put too much wear and tear on
the airplane and the brakes.
But you can tell I would have been able to stop with moderate braking at about 760 feet.
Again, a roughly thirty percent difference from what the ForeFlight app calculated.
Next up Dave Hirshman in a 1989 Bonanza.
Here comes the take-off roll starting at the thousand foot marker maximum effort.
ForeFlight calculated his ground roll at 912 feet.
Airspeed's alive.
Here comes my rotation speed now.
The bonanza finally takes off at about 1,220 feet.
Again, a roughly thirty percent difference than what was calculated by ForeFlight.
For landing ForeFlight calculated a distance of 911 feet and that's about what Dave achieved.
Interesting that this was the only parameter where the actual performance
met the ForeFlight calculation in either airplane.
The clips in this video are representative of the average performance Dave and I saw in each airplane.
We executed four takeoffs and four landings and saw very little variance between each pattern.
We at ASI saw two takeaways from this video. Number one, it reinforces our long-standing
recommendation to add fifty percent to your performance calculations. While we saw roughly a thirty percent difference in the numbers in our test,
remember that we had well-maintained airplanes on a near perfect day and pilots who are proficient in both airplanes.
So adding fifty just gives you a little added safety margin to the thirty percent that we saw in our test.
The second takeaway is this gives you a great reason to go fly. Take your ForeFlight
application, go out in the airplane that you fly and see how your performance and your technique in your airplane stacks up
against the ForeFlight calculated numbers.
Thanks to ForeFlight for making this critical performance data so easily available to pilots who sign up for their performance plus subscription.