Narrative:

I was the pilot not flying and the first officer was the pilot flying. Non-event flight until about 45 minutes into the flight. We were about 12-15 NM out on the ILS at 4;000-5;000 ft. We were just about to be switched over to the tower when -- all at the same time: captain's side eadi; ehsi; mfd went black. Captain's side airspeed; vsi; altimeter all read incorrectly (airspeed 250 KTS; vsi 6;000 FPM descent; altimeter at 0 ft?). Told by ATC that they lost our transponder; numerous lights on cwp; too many to name (configuration warning; avionics vent; rudder limits; etc.) however; not all were lit up. There was back lighting on captain's side instrument pack; but not one instrument was reading correctly; every instrument was completely useless on the captain's side. The first officer's instruments were all reading correctly; however; there were some red flags and red boxed items on the eadi. The first officer had no yaw damper; FD; autopilot available; he was flying on raw data. At the time of the event; we were IMC and it was quite distracting to all of a sudden have this happen; have cwp warnings and chimes going off; and ATC wondering what was going on and where we were at; and to make sure that the first officer was keeping us upright by scanning his instruments from the left seat. Items on the cwp would light up then go out; and some would stay on. There were so many on there; I can't remember the exact ones. I asked to be vectored off of the approach to run checklists and try to remedy the problem; and ATC did so. We were vectored away for about 3 minutes when all of a sudden all instruments came back on and everything was then working correctly. We were even told by ATC that our transponder was now working again. This happened before we even had the chance to run any checklists to remedy our problem and without us touching anything; besides just trying to fly the plane. With everything now working there were no checklists available to run and we notified ATC that we were ready for the approach. We then landed without incident.

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Original NASA ASRS Text

Title: SF340 on approach experiences multiple electrical failures. The crew requests vectors to run appropriate checklists; only for the problems to resolve themselves.

Narrative: I was the Pilot Not Flying and the First Officer was the Pilot Flying. Non-event flight until about 45 minutes into the flight. We were about 12-15 NM out on the ILS at 4;000-5;000 FT. We were just about to be switched over to the Tower when -- all at the same time: Captain's side EADI; EHSI; MFD went black. Captain's side airspeed; VSI; altimeter all read incorrectly (airspeed 250 KTS; VSI 6;000 FPM descent; Altimeter at 0 FT?). Told by ATC that they lost our transponder; numerous lights on CWP; too many to name (configuration warning; avionics vent; rudder limits; etc.) however; not all were lit up. There was back lighting on Captain's side instrument pack; but not one instrument was reading correctly; every instrument was completely useless on the Captain's side. The First Officer's instruments were all reading correctly; however; there were some red flags and red boxed items on the EADI. The First Officer had no yaw damper; FD; autopilot available; he was flying on raw data. At the time of the event; we were IMC and it was quite distracting to all of a sudden have this happen; have CWP warnings and chimes going off; and ATC wondering what was going on and where we were at; and to make sure that the First Officer was keeping us upright by scanning his instruments from the left seat. Items on the CWP would light up then go out; and some would stay on. There were so many on there; I can't remember the exact ones. I asked to be vectored off of the approach to run checklists and try to remedy the problem; and ATC did so. We were vectored away for about 3 minutes when all of a sudden all instruments came back on and everything was then working correctly. We were even told by ATC that our transponder was now working again. This happened before we even had the chance to run any checklists to remedy our problem and without us touching anything; besides just trying to fly the plane. With everything now working there were no checklists available to run and we notified ATC that we were ready for the approach. We then landed without incident.

Data retrieved from NASA's ASRS site as of May 2009 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.