DH6 pilot declared an emergency after having electrical failure in IMC.

Attributes
ACN	437099
Time
Date	199905
Day	Sun
Local Time Of Day	1801 To 2400
Place
Locale Reference	navaid : den.ils
State Reference	CO
Altitude	msl single value : 6020
Environment
Flight Conditions	IMC
Weather Elements	Thunderstorm Turbulence Ice
Light	Dusk
Aircraft 1
Controlling Facilities	tracon : d01.tracon
Operator	general aviation : personal
Make Model Name	Twin Otter DHC-6
Operating Under FAR Part	Part 91
Navigation In Use	ils localizer & glide slope : 35l
Flight Phase	descent : approach
Route In Use	approach : instrument precision
Flight Plan	IFR
Person 1
Affiliation	other
Function	flight crew : single pilot oversight : pic
Qualification	pilot : atp pilot : multi engine pilot : instrument
Experience	flight time last 90 days : 300 flight time total : 6200 flight time type : 3000
ASRS Report	437099
Person 2
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	other flight crewa
Resolutory Action	flight crew : declared emergency flight crew : executed missed approach flight crew : landed as precaution flight crew : landed in emergency condition
Consequence	other
Supplementary
Problem Areas	Aircraft
Primary Problem	Aircraft

Narrative:

Filed en route IFR plan from cos to apa. WX at apa was reported 800 ft scattered, 2500 ft broken, 3400 ft overcast. On the ILS into apa, tower advised slightly low of the GS. My GS was showing on slope. On the missed, decided to go to den as an alternate. Had an idea that there may have been a problem with the navs at this time. On the ILS at den (runway 35L) I showed on course and slope. On my descent about 12+ mi, I lot all navigation and directional gyro instruments. Approach advised I was 1 mi left of course and below MDA. On breakout of clouds, I spotted buckley ANG base, declared an emergency, and landed buckley. My decision to land buckley ANG was made to land the aircraft safely. I had 45 mins of fuel remaining and even though enough to try another approach into den I felt it unsafe with the electrical failure. All emergency checklists were run and all pertinent circuit breakers reset. Be advised I was single pilot in thunderstorm and rain. My first action was to fly the airplane. Landing at buckley was uneventful and no injuries occurred.

Original NASA ASRS Text

Title: DH6 PLT DECLARED AN EMER AFTER HAVING ELECTRICAL FAILURE IN IMC.

Narrative: FILED ENRTE IFR PLAN FROM COS TO APA. WX AT APA WAS RPTED 800 FT SCATTERED, 2500 FT BROKEN, 3400 FT OVCST. ON THE ILS INTO APA, TWR ADVISED SLIGHTLY LOW OF THE GS. MY GS WAS SHOWING ON SLOPE. ON THE MISSED, DECIDED TO GO TO DEN AS AN ALTERNATE. HAD AN IDEA THAT THERE MAY HAVE BEEN A PROB WITH THE NAVS AT THIS TIME. ON THE ILS AT DEN (RWY 35L) I SHOWED ON COURSE AND SLOPE. ON MY DSCNT ABOUT 12+ MI, I LOT ALL NAV AND DIRECTIONAL GYRO INSTS. APCH ADVISED I WAS 1 MI L OF COURSE AND BELOW MDA. ON BREAKOUT OF CLOUDS, I SPOTTED BUCKLEY ANG BASE, DECLARED AN EMER, AND LANDED BUCKLEY. MY DECISION TO LAND BUCKLEY ANG WAS MADE TO LAND THE ACFT SAFELY. I HAD 45 MINS OF FUEL REMAINING AND EVEN THOUGH ENOUGH TO TRY ANOTHER APCH INTO DEN I FELT IT UNSAFE WITH THE ELECTRICAL FAILURE. ALL EMER CHKLISTS WERE RUN AND ALL PERTINENT CIRCUIT BREAKERS RESET. BE ADVISED I WAS SINGLE PLT IN TSTM AND RAIN. MY FIRST ACTION WAS TO FLY THE AIRPLANE. LNDG AT BUCKLEY WAS UNEVENTFUL AND NO INJURIES OCCURRED.

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.