Narrative:

Took off msp en route to eau (tower visibility was 3/4 mi). En route the left a/C gen failed. Complied with light transport abnormal procedures A13 and advised ZMP of situation and desire to return to msp. (Procedure advises to leave icing conditions as soon as possible.) ZMP advised of traffic stop to msp as airport was below minimums. Elected to continue since was 3000' overcast and at MVA of 300' MSL (2100' AGL). We could exit icing conditions. Proceeded direct 'maggs' and descended to 3000' MSL. Still in WX and received clearance for ILS 22 at eau. While OM outbnd right a/C gen failed. Complied with abnormal procedure A13 and unable to get right a/G gen on-line. First officer's airspeed indicator frozen and went to 0. Declared emergency and requested crash fire rescue equipment with msp center, since aircraft lacked engine and flight INS icing protection other than standby pitot heat, and ice was forming on side windshields. Landed eau runway 22 west/O incident. The light transport manufacturer should find a way to allow 1 a/C gen to provide enough load to run both engine intake heats if necessary. Callback conversation with reporter revealed the following: left a/C gen was a malfunction due to internal failure. On this model aircraft, when 1 gen drops off the line the electrical load is automatically shifted to the other gen. When the reporter mentioned using the abnormal procedure A13, he responded to the question of whether this gave consideration to a load reduction in the negative. This non load reduction shift failed the right gen load control unit. His complaint re: the aircraft equipment design is that there is not enough power generated to run the heaters surrounding the air intake scoops, therefore allowing ice to build up and ultimately have the turbine ingest that ice. This occurs during 1 gen failure as the only electrical that does not shift to the other gen is the power to the intake heaters. On top of this, the heating mat is faulty in design by itself and he stated that every other day there is an aircraft down for maintenance for a heater replacement. In his situation, he felt that his aircraft was 3 mins away from losing 1 or both engines in the icing conditions. The flight handbook only references that, in that electrical failure scenario, the pilot should exit icing conditions immediately. The supplier that provides the electric mat has been changed from mfr a to mfr B, but that doesn't solve the xfer problems.

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Original NASA ASRS Text

Title: WX FACTORS AND THE LOSS OF 2 GENERATORS CAUSE PIC ON ACR LTT TO DECLARE EMERGENCY FOR LNDG AT DESTINATION.

Narrative: TOOK OFF MSP ENRTE TO EAU (TWR VISIBILITY WAS 3/4 MI). ENRTE THE LEFT A/C GEN FAILED. COMPLIED WITH LTT ABNORMAL PROCS A13 AND ADVISED ZMP OF SITUATION AND DESIRE TO RETURN TO MSP. (PROC ADVISES TO LEAVE ICING CONDITIONS ASAP.) ZMP ADVISED OF TFC STOP TO MSP AS ARPT WAS BELOW MINIMUMS. ELECTED TO CONTINUE SINCE WAS 3000' OVCST AND AT MVA OF 300' MSL (2100' AGL). WE COULD EXIT ICING CONDITIONS. PROCEEDED DIRECT 'MAGGS' AND DSNDED TO 3000' MSL. STILL IN WX AND RECEIVED CLRNC FOR ILS 22 AT EAU. WHILE OM OUTBND RIGHT A/C GEN FAILED. COMPLIED WITH ABNORMAL PROC A13 AND UNABLE TO GET RIGHT A/G GEN ON-LINE. F/O'S AIRSPD INDICATOR FROZEN AND WENT TO 0. DECLARED EMER AND REQUESTED CFR WITH MSP CENTER, SINCE ACFT LACKED ENG AND FLT INS ICING PROTECTION OTHER THAN STANDBY PITOT HEAT, AND ICE WAS FORMING ON SIDE WINDSHIELDS. LANDED EAU RWY 22 W/O INCIDENT. THE LTT MANUFACTURER SHOULD FIND A WAY TO ALLOW 1 A/C GEN TO PROVIDE ENOUGH LOAD TO RUN BOTH ENG INTAKE HEATS IF NECESSARY. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING: LEFT A/C GEN WAS A MALFUNCTION DUE TO INTERNAL FAILURE. ON THIS MODEL ACFT, WHEN 1 GEN DROPS OFF THE LINE THE ELECTRICAL LOAD IS AUTOMATICALLY SHIFTED TO THE OTHER GEN. WHEN THE RPTR MENTIONED USING THE ABNORMAL PROC A13, HE RESPONDED TO THE QUESTION OF WHETHER THIS GAVE CONSIDERATION TO A LOAD REDUCTION IN THE NEGATIVE. THIS NON LOAD REDUCTION SHIFT FAILED THE RIGHT GEN LOAD CTL UNIT. HIS COMPLAINT RE: THE ACFT EQUIP DESIGN IS THAT THERE IS NOT ENOUGH PWR GENERATED TO RUN THE HEATERS SURROUNDING THE AIR INTAKE SCOOPS, THEREFORE ALLOWING ICE TO BUILD UP AND ULTIMATELY HAVE THE TURBINE INGEST THAT ICE. THIS OCCURS DURING 1 GEN FAILURE AS THE ONLY ELECTRICAL THAT DOES NOT SHIFT TO THE OTHER GEN IS THE PWR TO THE INTAKE HEATERS. ON TOP OF THIS, THE HEATING MAT IS FAULTY IN DESIGN BY ITSELF AND HE STATED THAT EVERY OTHER DAY THERE IS AN ACFT DOWN FOR MAINT FOR A HEATER REPLACEMENT. IN HIS SITUATION, HE FELT THAT HIS ACFT WAS 3 MINS AWAY FROM LOSING 1 OR BOTH ENGS IN THE ICING CONDITIONS. THE FLT HANDBOOK ONLY REFS THAT, IN THAT ELECTRICAL FAILURE SCENARIO, THE PLT SHOULD EXIT ICING CONDITIONS IMMEDIATELY. THE SUPPLIER THAT PROVIDES THE ELECTRIC MAT HAS BEEN CHANGED FROM MFR A TO MFR B, BUT THAT DOESN'T SOLVE THE XFER PROBS.

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.