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Is FLEX displayed correctly for takeoff calculations?


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Please take a look at the following examples:



The first is a rather tight calculation for a 2000 meter runway and the second is a calculation for a long 4000 meter runway. The results differ only in the V speeds.

I would have expected, that the runway length have a much greater factor on the flex temperature, than on the V speeds. Is the calculated flex value displayed correctly? For comparison, TOGA results in exactly the same V speeds and MTOW (PERF), which I find hard to believe:


I also noticed, lifts off unnaturally light on long runways. Are those fast V speeds on long runways correct?

With the above example, it is also possible to perform a calculation for a 1800 Meter runway. In that case the MTOW is 139.2, which is below the entered TOW. I would have expected a warning in this case.

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I have figured out, I made a mistake here. The correct format appears to be in kg, not tons. In my example above 143100 instead of 143.1 seems to be correct. This gives much more plausible values. May I suggest changing the placeholder? ---.- made be believe, the entry was expected to be in tons.  And maybe a plausibility warning if the entered TOW is less than DOW for idiots like me?

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