What was found
AFTER CLIMBING THROUGH 10,000 RECEIVED TRIPLE CHIME AND CABIN ALTITUDE HI MESSAGE. PERFORMED QRH AND RETURNED TO DEPARTURE AIRPORT. (FLIGHT 3495) WHEN ARRIVING TO THE AIRCRAFT, THE PRESSURIZATION PANEL THE MODE WAS SET TO MANUAL, RATHER THAN BEING IN AUTO FOR NORMAL OPERATION. ASKED THE PILOTS IF THEY MOVED THE SELECTOR FROM AUTO INTO MANUAL, THEY COULD NOT REMEMBER. ASKED THE CAPTAIN WHAT REFERENCE HE USED FOR QRH PROCEDURES. THE ABNORMAL AND EMERGENCY PROCEDURES MANUAL USED DOES NOT HAVE THE FLIGHT CREW CHANGE THE POSITION OF THE MODE SELECTOR. THE ONLY INSTRUCTION FOR THE PRESSURIZATION CONTROL PANEL WAS FOR THE PILOTS TO PRESS THE DUMP BUTTON, WHICH THE CAPTAIN DID CONFIRM WAS DONE. REFERENCE AML 1973357 FOR SPEED TAPE REMOVAL AND REAPPLICATION. REFERENCE AML 1973367 FOR TROUBLESHOOTING. REFERENCE AML 1973390 FOR TROUBLESHOOTING. DURING TROUBLESHOOTING PER FIM TASK: 21-31-00-810-818-A NO DEFECTS WERE FOUND DURING REQUIRED VISUAL INSPECTIONS AND THE CABIN LEAKAGE TEST DURING PRESSURIZATION WAS WITHIN NORMAL LIMITS. FOLLOWING TROUBLESHOOTING AND WITH NOT FINDING ANY DEFECTS, OTHER THAN THE FINDING OF THE MODE S