B737-300 CREW HAD A CABIN; HIGH ALT WARNING HORN DEPARTING BUR.

Narrative

TKOF AND DEP WERE NORMAL (BURBANK RWY 33; FLAPS 5 DEGS; BLEEDS OFF) UNTIL CABIN ALT WARNING HORN SOUNDED PASSING 10500 FT MSL. WE IMMEDIATELY REQUESTED AND RECEIVED CLRNC TO DSND AND MAINTAIN 10000 FT MSL. WE ACCOMPLISHED THE QRC FOR CABIN ALT WARNING HORN AND DISCOVERED THE CABIN PRESSURIZATION CTL PANEL SELECTED TO MANUAL MODE (OUTFLOW VALVE IN OPEN POS). AUTO MODE SELECTED AND ACFT PRESSURIZED NORMALLY. HUMAN FACTORS: PRIOR TO DEPARTING BURBANK; THE FO HAD GIVEN THE ARPT FIRE DEPT A COCKPIT ORIENTATION ON VARIOUS EP'S; INCLUDING SECURING RUNNING ENGS AND ELECTRICAL PWR; DISCHARGING THE FIRE BOTTLES; AND EXECUTION OF THE EVAC QRC THE PRESSURIZATION MODE SELECTOR WAS INADVERTENTLY LEFT IN THE MANUAL DC POS AFTER EVAC QRC DEMONSTRATION. CAPT WAS UNAWARE OF THE DEMONSTRATION OF EVAC QRC TO THE FIRE DEPT. SUPPLEMENTAL INFO FROM ACN 572908: THE FO HAD BEEN ASKED TO PARTICIPATE IN A FAMILIARIZATION TRAINING SESSION FOR THE BURBANK FIRE DEPT PRIOR TO DEP. (CAP IN OPS.) WHILE ANSWERING QUESTIONS REGARDING THE EVAC CHKLIST; FO PLACED THE MODE SELECTOR IN MANUAL POS AND OPENED OUTFLOW VALVE. HE LATER OVERLOOKED REPOSITIONING THE SELECTOR TO AUTO. ALL OTHER SWITCHES WERE POSITIONED PROPERLY. TKOF WAS PACKS OFF; BLEEDS ON. CAPT WAS PNF; PACKS WERE TURNED ON SOP; AND CAPT VERIFIED CABIN 'PRESSURIZING.' (CABIN WAS ACTUALLY CLBING WITH ACFT.) DID NOT NOTICE THE MANUAL MODE SELECTED. (BRIGHT DAY/GREEN LIGHT; AND SWITCH PARALLEL WITH NORMAL POS.) CHKED WITH FLT ATTENDANTS TO VERIFY CONDITION OF CABIN AND PAX.