Narrative:

Shortly after reaching FL290, the right generator and AC xtie lockout light illuminated. The autoplt disengaged and the automatic pressurization failed. Attempts to control the cabin were unsuccessful. ATC was advised, an emergency was declared, and an emergency descent was begun. The most important priority was the unsatisfactory pressurization and passenger safety. During the emergency descent the right engine oil quantity and pressure indicated zero. The right engine was secured and the checklists were completed. It was determined that the right oil pressure and quantity were in fact operating normally, therefore, the right engine was restarted. A routine approach and landing at pit followed. Upon arrival at the gate a log entry was made. Callback conversation with reporter revealed the following information: the reporter is a first officer on an air carrier DC9-30. He said that the onset of the problem was sudden. The generator jumped off the line and when the flight crew checked the caution lights they noted that in addition to the normal generator and bus off lights the AC xtie light was also illuminated indicating that no other source would be accepted for the right bus. He said that as they were going through their abnormal checklists they realized that the cabin altitude was increasing. He said that he was unable to use the automatic control function of the pressurization system and the alternate and standby system could not stop the rising cabin altitude. The flight crew declared an emergency and were cleared down by the ARTCC controller. The descent was made to below 10000 ft before the masks dropped. They returned to pit. The reporter said that he has not learned of the cause of the electrical problems, but the aircraft was repaired and flying the next day.

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Original NASA ASRS Text

Title: AN ACR DC9 FLC, THE R GENERATOR FAILS WITH AN AC LOCKOUT AND AN AUTO PRESSURIZATION FAILURE. THEY MAKE AN AUTH EMER DSCNT WITHOUT INJURY OR MASK DEPLOYMENT AND RETURN TO THEIR DEP ARPT.

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 WAS DECLARED, AND AN EMER DSCNT WAS BEGUN. THE MOST IMPORTANT PRIORITY WAS THE UNSATISFACTORY PRESSURIZATION AND PAX SAFETY. DURING THE EMER DSCNT THE R ENG OIL QUANTITY AND PRESSURE INDICATED ZERO. THE R ENG WAS SECURED AND THE CHKLISTS WERE COMPLETED. IT WAS DETERMINED THAT THE R 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: THE RPTR IS A FO ON AN ACR DC9-30. HE SAID THAT THE ONSET OF THE PROB WAS SUDDEN. THE GENERATOR JUMPED OFF THE LINE AND WHEN THE FLC CHKED THE CAUTION LIGHTS THEY NOTED THAT IN ADDITION TO THE NORMAL GENERATOR AND BUS OFF LIGHTS THE AC XTIE LIGHT WAS ALSO ILLUMINATED INDICATING THAT NO OTHER SOURCE WOULD BE ACCEPTED FOR THE R BUS. HE SAID THAT AS THEY WERE GOING THROUGH THEIR ABNORMAL CHKLISTS THEY REALIZED THAT THE CABIN ALT WAS INCREASING. HE SAID THAT HE WAS UNABLE TO USE THE AUTO CTL FUNCTION OF THE PRESSURIZATION SYS AND THE ALTERNATE AND STANDBY SYS COULD NOT STOP THE RISING CABIN ALT. THE FLC DECLARED AN EMER AND WERE CLRED DOWN BY THE ARTCC CTLR. THE DSCNT WAS MADE TO BELOW 10000 FT BEFORE THE MASKS DROPPED. THEY RETURNED TO PIT. THE RPTR SAID THAT HE HAS NOT LEARNED OF THE CAUSE OF THE ELECTRICAL PROBS, BUT THE ACFT WAS REPAIRED AND FLYING THE NEXT DAY.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.