Back to Back in Crewing speak is in one day out the next. It's often associated with flights to/from the same place i.e. LHR-JFK-LHR then same again. The big difference is that the flights are relatively the same and the times relatively the same. If your having 36hrs inbetween that could mean your transitting night/day/night/day
horrible
Whilst the SAFE module will give a good idea common sense is more likely to give better indications of fatigue......
