AN ACR DC10 FLC LOSES PRESSURIZATION DURING CLB; MAKES AN EMER DSCNT AND RETURNS TO HNL. MAINT PERSONNEL DETERMINE THAT THE STANDBY PRESSURIZATION CTLR HAD FAILED.

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DECLARED EMER DUE TO RAPID DEPRESSURIZATION; DSNDED TO 10000 FT. WAS INSTRUCTED BY SFO COMMERCIAL RADIO TO SQUAWK XXXX AS PER OAK OCEANIC. RETURNED TO HNL. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THIS SO WAS HESITANT ABOUT REVEALING HIS TOTAL TIME AND EXPERIENCE LEVEL ON THE DC10-10. HE DID ADMIT TO GETTING IMPATIENT WITH THE AUTO PRESSURIZATION CTLR WHEN IT DID NOT SHOW A RISE IN CABIN ALT DURING THE EARLY CLBOUT. THE SO SAID THAT HE SWITCHED TO THE STANDBY PRESSURIZATION SYS TO GET THE ACFT BACK ON SCHEDULE. THE STANDBY SYS ALLOWS THE OPERATOR TO MANUALLY SELECT A POS FOR THE OUTFLOW VALVE. THIS SELECTION PROCESS IS SIMILAR TO THE MANUAL PRESSURIZATION SYS EXCEPT THAT THE STANDBY SYS DRIVES THE OUTFLOW VALVE MUCH FASTER (AN AC ELECTRICAL DRIVE VERSUS A DC ELECTRICAL DRIVE). THE FASTER DRIVE CAN PROMOTE AN OVERSHOOT SIT UNLESS IT IS CAREFULLY MONITORED; HOWEVER. THE RPTR SAID THAT HE REALIZED THAT HE HAD A PRESSURIZATION PROB WHEN THE CABIN ALT WARNING SOUNDED. HE SAID THAT THEY ACCOMPLISHED THE 'LOSS OF PRESSURIZATION CHKLIST' WITHOUT RECOVERING CTL OF THE OUTFLOW VALVE. THE CREW DECIDED TO RETURN TO HNL WHERE MAINT DETERMINED THAT THE STANDBY CTLR HAD FAILED. THE NEXT DAY THE FLC FERRIED THE ACFT BACK TO THE MAINLAND USING THE AUTO SYS WHICH WORKED NORMALLY. CALLBACK CONVERSATION WITH RPTR ACN 395076 REVEALED THE FOLLOWING INFO: RPTR STATED THE CAUSE OF THE CABIN DEPRESSURIZATION WAS THE FAILURE OF THE STANDBY PRESSURE CONTROLLER.