Calculating T/O Distance

[Bman.]

While the weather is warming up and me chewing up additional runway length today, I got to thinking about DA and performance calculations. I only know to do it with the performance charts in the POH for T/O and landing distances. Do you guys have a copy of the POH imported into ForeFlight library (or similar) .. or is there something else you use when calculating to double check?

For now, I will continue to use the paper chart - it works and I only know the chart but I want to make sure I am not missing something that will cross check me.

Benjamin

 

[James331]

I have it scanned and out into foreflight.

With time you just get a feel for it.

 

[Bman.]

Ok, thanks. I just tagged my .pdf of the POH by chapter and imported via Dropbox. Works well enough. Good thing I only had 2500' feet of runway left today to clear the 50' obstacle.

 

[F6F-Hellcat]

Koch Chart...

 

[fiveoboy01]

If there are factors that make it even somewhat questionable(shorter than average runway, full gross weight, hot temperatures), I'll run the numbers.

Otherwise I don't bother. For instance, it was 85 degrees this afternoon, but I was the only guy in the airplane, fuel to both tabs, and a 5800 foot runway is what I had to work with. Really no need to run calculations in that instance, unless I want to roughly know what I have left to land on after liftoff.

 

[Hank S]

I know this: unless nervous gross, I should be in the air around 1000', maybe 1100 if it's pushing 100°; in winter, it's much shorter. Learning and being based for seven years at a 3000' runway with trees at both ends, I needed to know so I made myself a chart with various loading situations and ran the numbers. For a couple of years, I kept it in the plane for reference. Now, I know my envelope.

 

[mondtster]

With time you just get a feel for it.

Indeed. Rather than banking on the performance charts for determining a go/no go when things are that tight I'd want to be fairly familiar with the airplane and how it actually performs. The charts are based on a standard issue airplane and things like STOL kits or prop changes will change the performance (sometimes for the better, sometimes not).

I'd suggest practicing normal, short and soft field takeoffs and landings at a larger, unobstructed airport and benchmark your performance there. Then once you know the airplane and whether you can do book performance in it you can progress to the smaller fields, and determine whether or not you can rely on the performance charts.

As an interesting side note, every student pilot I've worked with so far has been able to produce book performance numbers with a little practice. I like to have them do the calculations then compare what we actually do to what we were supposed to do.

 

[Let'sgoflying!]

Take whatever you conservatively estimate or calculate from charts and add 50%.

 

[MauleSkinner]

Take whatever you conservatively estimate or calculate from charts and add 50%.

Unfortunately this isn't reliable unless you compare those numbers with your actual performance as indicated in the previous post. It's not at all uncommon for actual performance to require more than a 50% addition due to technique.