Narrative:

Captain was the PF. Takeoff weight 605;000 lbs; 205;000 lbs of fuel on board. Climbing thru approximately 8;000 ft MSL; displays 4; 5; and 6 blanked-out completely; along with the number 2 mcdu (multi control display unit). The first officer observed a transient L1 'bus right emergency AC off' alert. The captain's pfd had a 'no compare' amber alert in the upper left corner of his display. The sd showed the r-emergency AC bus was de-powered. Additionally; an L2 'select fadec altn (alternate)' alert appeared. We leveled off at our present altitude (11;000) and advised ATC that we had an electrical malfunction. We ran the appropriate L2 checklist for attempting to reset the fadecs (unsuccessfully). We were unable to restore power to the failed right emergency AC bus; as there was no prescribed aom (aircraft operations manual) or QRH procedure for such a failure. Initially; there was some confusion about what the fundamental problem was - with the combination of altn fadec modes and the 'no compare' annunciator; the captain initially thought the malfunction could have been related to a CADC (central air data computer) failure(s) and would necessitate running the non-alert 'airspeed: unreliable' checklist. Subsequent discussions among the crew helped to clarify that the inoperative components in question were due to the de-powered AC bus. It also became apparent that we no longer had all the required equipment for rvsm and/or oceanic flight; we no longer had two operable independent primary altimeter systems and the number 2 mcdu was inoperative due to the failed electrical bus. At that time; the captain decided to 1) [advise] ATC; 2) coordinate an air turn back with ATC and company; and 3) initiate a fuel dump to land below maximum landing weight. An ACARS 'divert' message was sent by the first officer to the company. The cockpit workload was busy and frequently interrupted by ACARS messages from the company to coordinate with an engineer and maintenance control. To his credit; the captain specifically instructed the first officer and international relief officer to (paraphrasing) '...please stop worrying about communications with the company right now...' so as to focus on managing the irregularities; fuel dump; approach setup; and ongoing ATC coordination. We coordinated with ATC and proceeded to dump approximately 120;000 lbs of fuel in order to avoid landing overweight. The dump time took approximately 23-24 minutes; and occurred over an area determined by ATC via issuing radar vectors. While this was occurring; we set up and briefed our arrival. When the fuel dump was completed; we proceeded to the airport and were vectored onto the approach and landed in VMC conditions. We taxied to the gate under our own power and secured the aircraft without further incident.

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Original NASA ASRS Text

Title: MD-11 First Officer and IRO reported returning to the departure airport after experiencing loss of the right emergency AC bus.

Narrative: Captain was the PF. Takeoff weight 605;000 lbs; 205;000 lbs of fuel on board. Climbing thru approximately 8;000 ft MSL; displays 4; 5; and 6 blanked-out completely; along with the Number 2 MCDU (Multi Control Display Unit). The FO observed a transient L1 'BUS R EMERGENCY AC OFF' alert. The Captain's PFD had a 'NO COMPARE' amber alert in the upper left corner of his display. The SD showed the R-Emergency AC bus was de-powered. Additionally; an L2 'SELECT FADEC ALTN (Alternate)' alert appeared. We leveled off at our present altitude (11;000) and advised ATC that we had an electrical malfunction. We ran the appropriate L2 Checklist for attempting to reset the FADECs (unsuccessfully). We were unable to restore power to the failed R Emergency AC Bus; as there was no prescribed AOM (Aircraft Operations Manual) or QRH procedure for such a failure. Initially; there was some confusion about what the fundamental problem was - with the combination of ALTN FADEC modes and the 'no compare' annunciator; the Captain initially thought the malfunction could have been related to a CADC (Central Air Data Computer) failure(s) and would necessitate running the non-alert 'AIRSPEED: UNRELIABLE' checklist. Subsequent discussions among the crew helped to clarify that the inoperative components in question were due to the de-powered AC Bus. It also became apparent that we no longer had all the required equipment for RVSM and/or oceanic flight; we no longer had two operable independent primary altimeter systems and the Number 2 MCDU was inoperative due to the failed electrical bus. At that time; the Captain decided to 1) [advise] ATC; 2) coordinate an air turn back with ATC and Company; and 3) initiate a fuel dump to land below maximum landing weight. An ACARS 'Divert' message was sent by the FO to the Company. The cockpit workload was busy and frequently interrupted by ACARS messages from the company to coordinate with an Engineer and Maintenance Control. To his credit; the Captain specifically instructed the FO and IRO to (paraphrasing) '...please stop worrying about communications with the Company right now...' so as to focus on managing the irregularities; fuel dump; approach setup; and ongoing ATC coordination. We coordinated with ATC and proceeded to dump approximately 120;000 lbs of fuel in order to avoid landing overweight. The dump time took approximately 23-24 minutes; and occurred over an area determined by ATC via issuing radar vectors. While this was occurring; we set up and briefed our arrival. When the fuel dump was completed; we proceeded to the airport and were vectored onto the approach and landed in VMC conditions. We taxied to the gate under our own power and secured the aircraft without further incident.

Data retrieved from NASA's ASRS site 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.