In my last posting, sorry, I missed that the recorder was a Cambridge
20 because you put this under your name rather than in the text.

The problems associated with the three legacy Cambridge models 10, 20
and 25 when used for OLC flights, have been extensively discussed on
this newsroup. In terms of using the free VALI-CAM.exe program, this
only works with the binary CAI file and not with the IGC file that is
derived from it. And if you alter the IGC file, the VALI program will
register it as invalid because it has been altered.

By all means email the files (CAI and IGC) to me and I will look at
them with analysis software that enables every fix to be looked at in
detail. Some analysis software uses its own algorithms, for instance
to average things out. This may mean that some anomalies in fixing are
not obvious. As someone else said, you can always look at the
B-records in the IGC file itself, but this is better done through
analysis software designed to intepret them individually.

Ian Strachan
Chairman IGC GFA Committee