There are a couple of offline tools within the MAVLink package that can be used for a postflight analysis.
This can graph any of the flight data.
mavgraph.py flight.tlog VFR_HUD.alt
Other than specifying the tlog file, the commands are exactly the same as the graph module in MAVProxy.
Exports the GPS points in a logfile to the GPX format, which can be read by Google Earth.
Finds the ArduPilot parameters in a logfile and displays them on the console.
Prints out the total time spent in the air. Note that a threshold of
3m/s defines the difference between air time and ground time. This can
be changed by the
Prints out the timestamp and name of each flight mode change in a logfile.