**This description was originally written by Angelo Crapanzano**

**NOTE: this is not exactly how it is done in FS, it is the original way it was meant to be done (and possibly the way it is done in CompeGPS). It is shown here to give an understanding of the general principles, so do not get to hung up in the actual formulas shown.**

Here is how the Lc coefficient must be calculated. Be careful because there are several particular cases...

The Lc coefficient is calculated between Start and Arrival only or between Start and MaxDistance if nobody makes goal. (NOT between Takeoff and Goal)

Any pilot who did not fly (ABS, NYP, DNF) or did not correctly cross the Start line within the specified time, must get 0 or null Lc (please check what happens in Race in both cases) so to get 0 Leading points (please check, but I think numbers bigger than 24 are not accepted by the .DLL)

- Start must be accurately verified and timed (best for pilot between interpolation and extrapolation). A pilot started if he crossed the Start line within the Start opening time (if he started before the first start then will be penalized according to a formula I will tell you next time).

- If there is not a Start turnpoint then, of course, Start is Takeoff.

- Arrival must be accurately verified and timed the same way too. A pilot did arrive if he crossed the Arrival line before the task-end time. If nobody crosses the Arrival line then the Lc coefficient is calculated between Start and longest distance flown.

- If there is not an Arrival TP then, of course, Arrival is Goal.

- Before making the calculations the tracklog must be cleaned to take away the strange points which sometime appear when the coverage is missing (a good way to clean it automatically is to look at too high speeds; it should also be possible to delete a tracklog point right-clicking on it, to manually fix remaining problems). Please, only tracklogs from the task day must be shown.

- It would be good if in the Race report was written if the tracklog has been modified.

About the actual calculation of Lc:

- The name of the field in Race where Lc is written by Compe, has been changed to avoid old versions of Compe to write wrong data on it (check the new name).

- If a section of a tracklog is missing the missing part is replaced with a vertical and an horizontal line to avoid pilots only using the GPS at turnpoints to gain departure points.

Iv = the area in Km*s according to these two graphs:

if the pilot gets the finish line (with a missing part of the tracklog)

if the pilot lands before the finish line:

be careful: it's not shown in the time-distance graps above, but when the actual tracklog is going "backward" you should consider the line vertical (pilots are considered never going backward).

The "Lc" data RACE needs in the RcLeadingCoefficient field must be:

Lc = (Iv + An)/(1800*D)

(like this the area is transformed in a supposed elapsed time from first to start to pilot arrival, expressed in decimals hours)

where:

Iv = the area shown in the graphs above (in Km*s)

An = (A*D)+(C*M)

where:

A = PilotStart-FirstStart (if <0 then =0) [s]

D = SpeedSectionDistance [km]

C = LastPilot - PilotLanding [s]

M = PilotMissingDistance [km]

where all the data are in km or seconds and are:

PilotStart = actual start time of the pilot (if a pilot has more than one starts, the last one is the valid one)

FirstStart = the earliest PilotStart among pilots completing the SpeedSection

SpeedSectionDistance = the length in km of the speed section

PilotMissingDistance= the distance missing to get the Finish line (or Max distance)

PilotLanding = Landing time of the pilot

LastPilot = the latest landing time inside the SpeedSection or the latest Arrival time, whichever the greatest. Remember that if the day is stopped LastPilot cannot be bigger than the Stop Time.

FirstStart = the earliest PilotStart among pilots completing the SpeedSection; if nobody completes the speed section then use first start opening time.

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