What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
(-23) Briefing paper: subject: united parcel service (ups) MD11 N270UP air turn back (atb) due to loss of number 1 ac buss. Background: ups flight 6995 departed Anchorage, Alaska for inchon, korea. Approximately 2.5 hours into the flight at FL 360 the crew experienced a failure of the number 1 ac bus along with numerous circuit breakers popping (exact number and position unknown). Flight crew followed the emergency procedures outlined in their manual and returned to Anchorage. Aircraft landed uneventfully. When the number 1 ac generator bus failed the following systems became inoperative: tank 1 forward fuel pump, aux tail tank left transfer fuel pump, fuel quantity normal power, manifold fail detection loop 1, left windshield anti-ice control, ice diction controller engine 1, cac fan 1 (center accessory compartment), avionics rack fan 1 control, avionics compartment exhaust fan, avionics venture system control, esc channel b (environmental system control), turbine bypass valve pack 1, acc 1 auto control power (ac cabin bus control), number 1 hf transceiver, display units 1 and 3, display electronic unit 1, captains audio control panel, air date computer 1, engine ignition 1, 1-3 isolation valve control, standby horizon, altimeter backup lights, VOR 1, packs 1, 2, and 3 ram air door backup power, multi-function control display unit 1. When all this took place the crew received an alert and consequence message that stated "bus ac 1 off GPWS inop auto ground spoilers inop". Discussion: ups maintenance working with ups tech support in louisville identified the problem as a failed rccb (remote control circuit breaker) for the "a" phase of ac generator bus 1, (item number B1-174). When this breaker failed all components that are 3 phase had their phase "b" and "c" circuit breakers pop. The rccb was replaced and maintenance performed the appropriate operational checks and all was found to function normally. Because this office was concerned about a comment in the log book which mentioned a loss of "#1 comm" this office requested that ups maintenance duplicate the problem and check the number 1 VHF for proper operaiton. A check was performed as requested and the number 1 VHF comm functioned normally. This office would like to point out that this type of failure is identified in the abnormals section of the flight manual. The crew followed these procedures success fully. Note: the initial report sent by the Anchorage FSDO mentioned "all irus failed" this was not the case. The crew still had attitude reference information as well as navigational information. privacy data omitted
As the FAA filed it
(-23) BRIEFING PAPER: SUBJECT: UNITED PARCEL SERVICE (UPS) MD11 N270UP AIR TURN BACK (ATB) DUE TO LOSS OF NUMBER 1 AC BUSS. BACKGROUND: UPS FLIGHT 6995 DEPARTED ANCHORAGE, ALASKA FOR INCHON, KOREA. APPROXIMATELY 2.5 HOURS INTO THE FLIGHT AT FL 360 THE CREW EXPERIENCED A FAILURE OF THE NUMBER 1 AC BUS ALONG WITH NUMEROUS CIRCUIT BREAKERS POPPING (EXACT NUMBER AND POSITION UNKNOWN). FLIGHT CREW FOLLOWED THE EMERGENCY PROCEDURES OUTLINED IN THEIR MANUAL AND RETURNED TO ANCHORAGE. AIRCRAFT LANDED UNEVENTFULLY. WHEN THE NUMBER 1 AC GENERATOR BUS FAILED THE FOLLOWING SYSTEMS BECAME INOPERATIVE: TANK 1 FORWARD FUEL PUMP, AUX TAIL TANK LEFT TRANSFER FUEL PUMP, FUEL QUANTITY NORMAL POWER, MANIFOLD FAIL DETECTION LOOP 1, LEFT WINDSHIELD ANTI-ICE CONTROL, ICE DICTION CONTROLLER ENGINE 1, CAC FAN 1 (CENTER ACCESSORY COMPARTMENT), AVIONICS RACK FAN 1 CONTROL, AVIONICS COMPARTMENT EXHAUST FAN, AVIONICS VENTURE SYSTEM CONTROL, ESC CHANNEL B (ENVIRONMENTAL SYSTEM CONTROL), TURBINE BYPASS VALVE PACK 1, ACC 1 AUTO CONTROL POWER (AC CABIN BUS CONTROL), NUMBER 1 HF TRANSCEIVER, DISPLAY UNITS 1 AND 3, DISPLAY ELECTRONIC UNIT 1, CAPTAINS AUDIO CONTROL PANEL, AIR DATE COMPUTER 1, ENGINE IGNITION 1, 1-3 ISOLATION VALVE CONTROL, STANDBY HORIZON, ALTIMETER BACKUP LIGHTS, VOR 1, PACKS 1, 2, AND 3 RAM AIR DOOR BACKUP POWER, MULTI-FUNCTION CONTROL DISPLAY UNIT 1. WHEN ALL THIS TOOK PLACE THE CREW RECEIVED AN ALERT AND CONSEQUENCE MESSAGE THAT STATED "BUS AC 1 OFF GPWS INOP AUTO GROUND SPOILERS INOP". DISCUSSION: UPS MAINTENANCE WORKING WITH UPS TECH SUPPORT IN LOUISVILLE IDENTIFIED THE PROBLEM AS A FAILED RCCB (REMOTE CONTROL CIRCUIT BREAKER) FOR THE "A" PHASE OF AC GENERATOR BUS 1, (ITEM NUMBER B1-174). WHEN THIS BREAKER FAILED ALL COMPONENTS THAT ARE 3 PHASE HAD THEIR PHASE "B" AND "C" CIRCUIT BREAKERS POP. THE RCCB WAS REPLACED AND MAINTENANCE PERFORMED THE APPROPRIATE OPERATIONAL CHECKS AND ALL WAS FOUND TO FUNCTION NORMALLY. BECAUSE THIS OFFICE WAS CONCERNED ABOUT A COMMENT IN THE LOG BOOK WHICH MENTIONED A LOSS OF "#1 COMM" THIS OFFICE REQUESTED THAT UPS MAINTENANCE DUPLICATE THE PROBLEM AND CHECK THE NUMBER 1 VHF FOR PROPER OPERAITON. A CHECK WAS PERFORMED AS REQUESTED AND THE NUMBER 1 VHF COMM FUNCTIONED NORMALLY. THIS OFFICE WOULD LIKE TO POINT OUT THAT THIS TYPE OF FAILURE IS IDENTIFIED IN THE ABNORMALS SECTION OF THE FLIGHT MANUAL. THE CREW FOLLOWED THESE PROCEDURES SUCCESS FULLY. NOTE: THE INITIAL REPORT SENT BY THE ANCHORAGE FSDO MENTIONED "ALL IRUS FAILED" THIS WAS NOT THE CASE. THE CREW STILL HAD ATTITUDE REFERENCE INFORMATION AS WELL AS NAVIGATIONAL INFORMATION. ^PRIVACY DATA OMITTED^
Other reports on N270UP · 1
Matched to the same aircraft by N-number and date.