Analyzing Flights with Many Missed Laps

The TT application programme is able to detect that a lap registration is missed by the timing "hole" that appears. After being alerted by the software, the operator can choose to reconstruct the missing lap indication through interpolation. However, this requires that the surrounding lap indications are fairly regular.

If there are many missed laps close to each other, this method does not work. The start and stop registrations of the timed flight are important, while the lap registrations inside the timed flight only serve to count the laps correctly. If there are misses, in many cases the correct count can be reconstructed manually. This is preferrable to granting the competitor a reflight.

When lap registrations are missing, one should seek to reconstruct the proper lap count, and then see if the the start and stop times of the timed flight are properly registered. Unless the speed is varying wildly, there is seldom any problem to correctly reconstruct the lap count by looking manually at the time stamps.

Let's have a look at an actual example from the 2006 World Champs log file: 


# TT	F2A	Wed Jul 19 2006	09:31:25	Round:   1	WORLD CHAMPS 06
# Comp:	29	FEDOTOV, Konstantin		Attempt: 1
# ETime	MTime1	MTime2	MTime3	ESpeed	MSpeed	EResult	MResult	Ruling
 0.0000	 0.00	 0.00	 0.00	  0.0	  0.0
# Individual laps:
# Lap   Speed(km/h) Time Stamp  Course Speed(km/h)
  0		   36.7276826
  1	 81.835	   41.6155752
  2	113.319	   45.1454486
  3	166.497	   47.5478932
  4	225.631	   49.3207025
  5	269.836	   50.8030831
  6	278.847	   52.2375617
  7	283.210	   53.6499401
  8	287.507	   55.0412109
  9	289.361	   56.4235655	182.779
  10	290.448	   57.8007505	222.426
  11	290.912	   59.1757379	256.588
  12	291.142	   60.5496366	276.886
  13	 97.274	   64.6617140	234.665
  14	292.505	   66.0292118	236.436
  15	 97.669	   70.1246858	201.262
  16	285.906	   71.5237470	201.412
  17	215.150	   73.3829157	196.274
# Handle Events:
# Engaged   	   55.3353751
# Disengaged	   67.7450277
Here the timing looks as it is quite in order until lap 13 and lap 15. Here the speed registered is close to 1/3 of the neighbouring speeds, so it is quite easy to tell that two laps registrations in a row are missing.

From the time when the handle engagement is registered, with the time stamp of 55.3353751 seconds, one can count the countdown laps, and determine that the start of the timed flight is at lap 11. Then we find: 


Timed lap	Registered lap
0		11
1		12
2		missing
3		missing
4		13
5		14
6		missing
7		missing
8		15
9		16
Clearly both the start and stop of the timed flight are correctly registered. The time becomes the difference between the times tamps for laps 11 and 16:
71.5237470 s - 59.1757379 s = 12.3480091 s
The resulting speed is 3600 / 12.3480091 = 291.544974647 km/h.

The final thing to do is to check that this result is consistent with the speeds of the individual laps, and with the F2A judge's impression of the flight. This is clearly the case here.

So, an official speed of 291.5 km/h would have been possible to determine from the existing data. I did the calculation as above on site, but the procedure was rejected by the FAI jury. Instead, Konstantin Fedotov was granted a reflight. Fortunately, he improved in round 3, so this flight had no influence of the outcome.