A C130 CREW; ENRTE AT FL200; MISSED A TURN POINT IN THEIR FLT PLAN; DEVIATING FROM CLRED RTE.

Narrative

FLT PLAN WAS J104-KOFFA-J65-BLH AT FL200. INSTRUCTOR PLT HAD CHARGE OF RADIOS WHILE COPLT FLEW THE ACFT. AT CRUISE; INSTRUCTOR PLT INITIATED A DISCUSSION OF THE C130 FUEL SYS WITH THE COPLT. COPLT BECAME INVOLVED IN THE DISCUSSION AND MISSED THE TURN POINT AT KOFFA. NEITHER NAVIGATOR NOR INSTRUCTOR PLT REALIZED THE OVERFLT UNTIL ZAB CALLED. INSTRUCTOR PLT MADE IMMEDIATE L TURN TOWARD BLYTH (BLH) AND ASKED FOR DIRECT BLH; WHICH ZAB GRANTED. ACFT WAS 10 DME PAST KOFFA WHEN ZAB CALLED AND AN IMMEDIATE L TURN WAS INITIATED. PERSONS AT FAULT INCLUDE THE NAVIGATOR; THE COPLT; AND THE INSTRUCTOR PLT. INSTRUCTOR PLT NEGLECTED TO EMPHASIZE 'FLYING THE AIRPLANE FIRST' PRIOR TO INITIATING THE FUEL SYS DISCUSSION. NAVIGATOR DID NOT CATCH THE OFF COURSE INCIDENT IN TIME. INSTRUCTOR PLT ALSO NEGLECTED TO SUPERVISE THE COPLT CLOSELY ENOUGH TO CATCH THE TURN POINT OVERFLT IN TIME. AFTER LNDG; INSTRUCTOR PLT CONDUCTED A FRANK AND OPEN CREW AND SUPERVISORY DEBRIEF OF THE INCIDENT TO PREVENT A RECURRENCE OF THIS SIT.