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1

pre-VNAV/early VNAV days we used FL x 3 plus/minus 10% of avg wind component and added 15nm for decel if the vector/STAR/approach and landing was more or less 'straight in', or 10nm for a vector to base turn or 5nm for vectors equivalent to a downwind. alternately, FL divided by 3. +/- avg wind comp and add 5 nm for a straight in. Keep recalculating and ...

2

Yes, there were refinements to it. In the 737-200, 3:1 was a 250 knot descent, while 280 knots was 2.5:1, and 320 knots was 2:1. The book also said add/subtract 1NM per 10 knots of tail/head wind, although that's a pretty rough wag. The newer 737's are cleaner, so 3:1 is a better bet at the typical 280 kt descent, and slowing to 250 will flatten things out ...

0

The reason the V1 adjustment works in this fashion is because V1 is the decision speed at which the aircraft can continue on the runway surface remaining, get airborne, and climb to the (adjusted) screen height with one engine inoperative before reaching the end of the Clearway, or stop on the remaining runway surface plus any Stopway. The function of "...

2

I wouldn't bother with polynomials (higher than 1 :). Just tabulate the original graphs at the convenient points and use linear interpolation. Being an aerospace engineer, I could come up with physical formulae for most things. But there are problems. First, this effectively means creating a model, which would need to be extensively validated through the ...

7

If you have a good set of well-spaced points, a best-fit polynomial in $x^2$ or $x^3$ is usually good enough. It's true that high-degree polynomials oscillate, and are therefore unreliable, but you're safe with squares and cubes... This site is free and quite good: MyCurveFit.

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