VARIOUS DISTRS AND THE ABSENCE OF THE TRAINING CAPT FROM THE COCKPIT ON AN ACR IOE FLT RESULTS IN A TRACK DEV AND AN ALT EXCURSION.

Narrative

I WAS THE PF. I WAS GIVING IOE TO THE FO; WHO IS A NEW HIRE CAPT; AND I WAS PERFORMING THE DUTIES OF CHK AIRMAN AND CAPT. OUR COMPANY WANTS ALL NEW HIRE CAPTS TO HAVE AT LEAST A DAY'S FO R SEAT TRAINING IN THE EVENT THEY HAVE TO FLY AS AN FO AT SOME TIME IN THE FUTURE. I HAD TO LEAVE THE COCKPIT FOR PHYSIOLOGICAL REASONS. THEREFORE; I LEFT THE IOE CANDIDATE IN THE R SEAT TO PERFORM THE PF DUTIES WHILE I WAS GONE AND FOLLOWED THE COMPANY POLICY BY HAVING THE LEAD FLT ATTENDANT COME INTO THE COCKPIT TO SECURE THE DOOR (COCKPIT) WHILE I WAS ABSENT. I WAS GONE APPROX 3 MINS; AND WHEN I RETURNED; I WAS INFORMED BY THE PF (IOE CANDIDATE) IN THE R SEAT; THAT THE AUTOPLT HAD DISCONNECTED AND THE HDG HAD VARIED BY APPROX 40 DEGS L OF COURSE (WE WERE CLRED TO GVE) AND THE ALT HAD RISEN TO APPROX FL282 (+200 FT) AS HE HAD NOT NOTICED WHEN THE AUTOPLT DISENGAGED. I WAS INFORMED THAT THE CTLR QUERIED US ABOUT THE HDG; BUT NOT THE ALT; AND ASKED IF WE WERE ON A HDG. THE PF CANDIDATE HAD ALREADY BEGUN TO MAKE CORRECTIONS TO GET THE ACFT BACK ON COURSE AND ALT AS I WAS ENTERING THE COCKPIT COMING BACK FROM THE LAVATORY. THE PF STATED THAT HE WAS DISTR BY THE FLT ATTENDANT'S QUESTION IN REGARDS TO THE WX RADAR; AND AS THE TSTM LIGHTS HAD BEEN PREVIOUSLY TURNED ON TO FACILITATE FILLING OUT THE FLT PLAN; THIS CAUSED THE AUTOPLT TO DISCONNECT RED LIGHT TO HAVE A DIMINISHED INTENSITY. THE AUTOPLT #1 MAY HAVE DISCONNECTED AS A RESULT OF TURB; AND IS UNDER EVALUATION. SUPPLEMENTAL INFO FROM ACN 574347: WE WERE AT FL280 IN LIGHT TO MODERATE TURB WITH TSTM LIGHTS ON; CAUSING THE COCKPIT TO BE BRIGHTLY LIT. I DID NOT NOTICE THE AUTOPLT LIGHT FLASHING WHEN THE AUTOPLT INADVERTENTLY CLICKED OFF. I'M NOT CERTAIN HOW LONG IT WAS OFF; BUT HDG CHANGED ABOUT 40 DEGS SLOWLY AND ALT BEGAN TO DRIFT UPWARDS. I NOTICED THE PROB WHEN THE ALT ALERTER LIGHT CAME ON WITH AURAL WARNING. CORRECTED HDG AND ALT IMMEDIATELY.