DC9-30 MAINTAINING FL290 LOST THE R GENERATOR AND AC XTIE LOCKOUT LIGHT ILLUMINATED. AUTOPLT DISENGAGED AND AUTOPRESSURIZATION CTL FAILED. EMER WAS DECLARED AND RETURN TO PIT. NOTED LOSS OF OIL PRESSURE AND QUANTITY R ENG SO SHUT DOWN. COMPLETING CHKLIST STARTED APU REGAINING ELECTRICAL PWR TO THE R AC BUS AND HAD NORMAL INDICATIONS ON OIL PRESSURE AND QUANTITY. RESTARTED R ENG AND LANDED NORMALLY PIT. OXYGEN MASKS NEVER DEPLOYED.

Narrative

SHORTLY AFTER REACHING FL290; THE R GENERATOR AND AC XTIE LOCKOUT LIGHT ILLUMINATED. THE AUTOPLT DISENGAGED AND THE AUTO PRESSURIZATION FAILED. ATTEMPTS TO CTL THE CABIN WERE UNSUCCESSFUL. ATC WAS ADVISED; AN EMER DECLARED; AND AN EMER DSCNT WAS BEGUN. THE IMPORTANT PRIORITY WAS UNSATISFACTORY PRESSURIZATION AND PAX SAFETY. DURING THE EMER DSCNT; THE R ENG OIL QUANTITY AND PRESSURE INDICATED ZERO. THE R ENG WAS SECURED AND CHKLISTS WERE COMPLETED. IT WAS DETERMINED THAT THE R ENG OIL PRESSURE AND QUANTITY WERE IN FACT OPERATING NORMALLY. THEREFORE; THE R ENG WAS RESTARTED. A ROUTINE APCH AND LNDG AT PIT FOLLOWED. UPON ARR AT THE GATE; A LOG ENTRY WAS MADE. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR ADVISED WITH AC XTIE LOCKOUT THE R AC BUS WAS LOST CAUSING LOSS OF THE CAPT INSTS. FEELS THE ELECTRICAL FAILURE COMPOUNDED THE PRESSURIZATION PROB. THEY WERE STILL HAVING PROBS TRYING TO CTL THE CABIN IN MANUAL AND ELECTED TO DECLARE AN EMER AND RETURN TO PIT. NOTED NO OIL QUANTITY OR PRESSURE ON THE R ENG AND ELECTED TO SHUT DOWN. COMPLETING THE CHKLIST STARTED THE APU; WHICH PWRED THE R AC BUS; RESULTING IN ENG OIL AND PRESSURE REGISTERING NORMAL. RESTARTED THE R ENG AND MADE A NORMAL 2 ENG LNDG. AT LOWER ALT CABIN STABILIZED AND THE MASKS WERE NOT DEPLOYED. ATC PROVIDED PRIORITY HANDLING FOR THE DSCNT AND APCH TO PIT. MAIN CONCERN WAS A POSSIBLE ENG EXPLOSION RUPTURING THE CABIN CONSEQUENTLY THE DECLARING EMER.