Narrative:

Inflight; had the following caution lights illuminate: right stall warning; elevator horn heat; and right tru. Had first officer confirm on AC meters panel whether the right AC bus had faulted; or if the right AC generator had failed. Also noted that we had lost the right propeller heat system; and right engine inlet heat; but yet we did not have a right AC bus fault caution light. Asked first officer to check the right tru loadmeter. It read zero. Asked first officer if the right tru circuit breaker had popped; which he stated it was. I called for the appropriate checklists; increased engine RPM; double-checked igniters were selected on; and requested a climb to exit icing conditions. We declared an emergency to receive priority altitude handling from ATC; and also because of the systems failure. Found that the right AC generator a and B phases had failed; but right C phase operated normally. Confirmed by feeling the right windshield; which was still warm; showing the C phase still operated. The left standby hydraulic pump showed full pressure when selected on; but we briefed that it could not be relied upon in the event of left engine failure; because it was probably only operating on one phase out of three; and when placed under consumer loads; the pressure might drop. In any event the engine driven hydraulic pumps were still both operating normally. The right auxiliary fuel pump did not operate. Two deicer boots on the right wing did not operate properly; probably due to the distributor valve heat failure in flight; which consumes AC power. (Right after takeoff they all had been operating normally.) we climbed aloft to exit icing; and found a clear area in very light icing; in which we remained. When it became necessary to descend; requested that ATC descend us to minimum vector altitude; to seek warmer air aloft and minimize any icing. Although we were cleared down to 3;000 ft; leveled out back to 5;000; since we were in the clear; and had begun to encounter moderate turbulence at 4;000 ft. ZZZ was above freezing temperature; so we knew that any ice accumulation would melt off during the approach (which it did); and would not cause a problem. Notified ZZZ operations of our emergency; and asked that dispatch be notified. Landed at ZZZ uneventfully. On the after start checklist; noticed that #2 auxiliary fuel pump advisory light did not illuminate. Cycled switch; and pump operated normally. Cycled again and operated normally thereafter. Decided to advise maintenance department of the glitch and to make an informational write-up at destination. During flight; decided to test pump again; to check if it was an intermittent problem. Operating the pump this time caused the above failures described.

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Original NASA ASRS Text

Title: Multiple 'right' electrical system anomalies lead DHC-8 flight crew to discover two of three phases of the right AC electrical system had failed.

Narrative: Inflight; had the following caution lights illuminate: Right Stall Warning; Elevator Horn Heat; and Right TRU. Had First Officer confirm on AC meters panel whether the right AC Bus had faulted; or if the right AC Generator had failed. Also noted that we had lost the right PROP heat system; and right engine inlet heat; but yet we did not have a right AC Bus Fault caution light. Asked First Officer to check the right TRU loadmeter. It read zero. Asked First Officer if the right TRU CB had popped; which he stated it was. I called for the appropriate checklists; increased engine RPM; double-checked igniters were selected on; and requested a climb to exit icing conditions. We declared an emergency to receive priority altitude handling from ATC; and also because of the systems failure. Found that the right AC Generator A and B phases had failed; but right C phase operated normally. Confirmed by feeling the right windshield; which was still warm; showing the C phase still operated. The left standby hydraulic pump showed full pressure when selected on; but we briefed that it could not be relied upon in the event of left engine failure; because it was probably only operating on one phase out of three; and when placed under consumer loads; the pressure might drop. In any event the engine driven hydraulic pumps were still both operating normally. The right auxiliary fuel pump did not operate. Two deicer boots on the right wing did not operate properly; probably due to the distributor valve heat failure in flight; which consumes AC power. (Right after takeoff they all had been operating normally.) We climbed aloft to exit icing; and found a clear area in very light icing; in which we remained. When it became necessary to descend; requested that ATC descend us to minimum vector altitude; to seek warmer air aloft and minimize any icing. Although we were cleared down to 3;000 FT; leveled out back to 5;000; since we were in the clear; and had begun to encounter moderate turbulence at 4;000 FT. ZZZ was above freezing temperature; so we knew that any ice accumulation would melt off during the Approach (which it did); and would not cause a problem. Notified ZZZ Operations of our emergency; and asked that Dispatch be notified. Landed at ZZZ uneventfully. On the after start checklist; noticed that #2 auxiliary fuel pump advisory light did not illuminate. Cycled switch; and pump operated normally. Cycled again and operated normally thereafter. Decided to advise Maintenance Department of the glitch and to make an informational write-up at destination. During flight; decided to test pump again; to check if it was an intermittent problem. Operating the pump this time caused the above failures described.

Data retrieved from NASA's ASRS site as of April 2012 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.