First Check - examine plot (1D or 2D) of data amplitudes and phases versus time and/or baseline looking for discrepant blocks of data

In AIPS this is most easily accomplished graphically with the task TVFLG, while in DIFMAP this is carried out in vplot

Patterns can discriminate between antenna-based errors or baseline dependent errors, also check whether problem appears in all IFs and polarizations

Often easier to look at amplitude and phase differences versus running mean to find discrepant blocks of integrations

Keep a record of strange behavior and forward to the apppropriate contact person - may be signature of software or hardware failure

Keep in mind that single bad integrations can have a greatly diluted effect on the results, while antennas or large time blocks with small offsets can have a large effect!