Takeoff Distance Limit Calculator
Software Application for the BlackBerry

About the Calculation (AKA "Alternate Step 5"):
See figure 2.5.3 (p2-44) in the FOM.

You might be able to use this procedure if:

The object of the calculation is simply to determine the maximum takeoff distance which would allow you to make the published climb gradient, by taking credit for unused runway. This tool does the calculation for you (including rounding the "runway length decrement" up to the nearest 1000ft, as per the FOM), and displays the result on the last line.  You need only enter the following 5 numbers:

Result ("T/O Dist Limit") - Compare the result to your required takeoff distance (from the AFM, dispatch flight release, or other source of certified performance data).

"Real World" uses:
LaGuardia 1 departure (excluding the Coney & Maspeth climbs - probably)
KSFO: All departures including Dumbarton 6, Eugen 5, Gap 3, Luvve 2, Molen 3, Offshore 5, Porte 3, Quiet 2, Rebas 3, San Francisco 8 & Shoreline 1
If you come across any others, send them to me and I'll post them: karl@kwvv.net