MD80 CREW HAD A TRACK DEV IN P50 CLASS B.

Narrative

DEPARTING PHX ON THE ST JOHNS 2 DEP AT 2000 FT AGL; FO STARTS TO TURN THE ACFT TO HEADING 350 DEGS (4-5 MI DME FROM PXR). I (THE CAPT) TOLD THE FO TO FLY THE DEP IN LNAV AND PUSH THE LNAV BUTTON. INSTEAD; THE FO HAND FLIES THE ACFT AND IS NOW N OFF COURSE. APCHING THE 9 MI FIX; I (CAPT) TELL THE FO TO FLY HEADING 350 DEGS AND JUST STAY ON THAT HEADING. FO MAKES ABRUPT TURN TO 040 DEGS (HAND FLYING) WHILE LOOKING DOWN ON THE COCKPIT FLOOR FOR HIS DEP PLATE. CAPT TAKES CTL OF ACFT AT THIS TIME. ATC TELLS US TO JUST FLY OUR PRESENT HEADING (040 DEGS) AND CLRS US TO NEXT FIX. FO NEVER FOLLOWED THE CAPT'S INSTRUCTIONS: A) FLY THE DEP IN LNAV. B) FLY HEADING 350 DEGS AFTER 9 MI FIX. CAPT SHOULD HAVE TAKEN CTL OF ACFT SOONER AFTER FIRST DEV AND SEEING THAT THE FO WAS NOT FOLLOWING MY COMMANDS. FO WAS NEW TO AIRLINE WITH NO PREVIOUS AIRLINE EXPERIENCE. FO NEVER USED THE AUTOPLT; NOR THE FMS GUIDANCE. THE ACFT FLEW SLIGHTLY OUTSIDE THE DEP BOUNDARY. THE CAPT AND FO WERE ON DUTY FOR 7 HRS AT TIME OF DEV.