Narrative:

Upon takeoff and at approximately 1000 ft AGL; the primary flight display on both sides went blank and subsequently became dark. I notified departure that we needed to return to the airport. We were given a radar vector back toward the field and told to contact the tower. I then noticed that both generators had failed as well as both invertors. I then requested priority handling from the tower and was given a radar vector that basically placed us on a base leg for runway 4R. At that point I noticed that the radio reception was weakening and the radios subsequently failed. We lined up on runway 4R and landed with no radios. We exited runway 4R and shut down the engines. Airport operations and fire rescue responded to our location and after an initial discussion and safety inspection; called the FBO to tow the aircraft. After numerous conversations with several different mechanics; the prevailing theory for the total electrical failure was the 'cold start - flight normal - ground power' switch may have been inadvertently bumped into the 'cold start' position which would have placed the batteries in a series vs parallel position and have possibly caused an over voltage situation which would have tripped both generators off line as well as drained the batteries. Both batteries were subsequently pulled from the aircraft for testing and recharging. In closely examining the above mentioned 3-WAY switch; it is apparent that it would be very easy to inadvertently move this switch out of the 'flight normal' position and into the 'cold start' position. Given the significant negative impact to the electrical system if this happens; it is my opinion that this switch should be guarded in some manner in order to prevent this type of occurrence.callback conversation with reporter revealed the following information: reporter stated that the electrical power control switch is located on the overhead panel in the cockpit and has three positions: gpu (isolates the batteries for ground power use); flight normal (places the batteries in parallel and lets the generators supply normal power); cold start (places the batteries in series for extra voltage to start a cold engine). In the cold start position the battery voltage supplied is doubled and this caused the over voltage tripping the generator. When queried regarding a 'loss of electric power' checklist; the reporter stated that there was a low ceiling and with the loss of the primary instruments the flight crew felt there was not time to read the checklist and maintain visual reference for landing. Their primary objective was to get the aircraft on the ground. He stated that by the time they returned for landing and touched down; the aircraft was completely dark with no lights on in the cockpit; there was total electrical power loss. He indicated that there is no place on the lineup or taxi checklist that mentions this switch. Also; there is no warning light that would indicate the position of the switch to the flight crew. He stated that the local FAA representative; after reviewing the incident; suggested that the switch position be placed on the lineup checklist. Additionally the reporter suggested that the switch be guarded.

Google
 

Original NASA ASRS Text

Title: FALCON 20 FLT CREW HAS LOSS OF ELECTRICAL POWER AND PRIMARY INSTRUMENTS ASSOCIATED WITH MISSET ELECTRICAL POWER CONTROL SWITCH

Narrative: UPON TAKEOFF AND AT APPROX 1000 FT AGL; THE PRIMARY FLT DISPLAY ON BOTH SIDES WENT BLANK AND SUBSEQUENTLY BECAME DARK. I NOTIFIED DEP THAT WE NEEDED TO RETURN TO THE ARPT. WE WERE GIVEN A RADAR VECTOR BACK TOWARD THE FIELD AND TOLD TO CONTACT THE TWR. I THEN NOTICED THAT BOTH GENERATORS HAD FAILED AS WELL AS BOTH INVERTORS. I THEN REQUESTED PRIORITY HANDLING FROM THE TWR AND WAS GIVEN A RADAR VECTOR THAT BASICALLY PLACED US ON A BASE LEG FOR RWY 4R. AT THAT POINT I NOTICED THAT THE RADIO RECEPTION WAS WEAKENING AND THE RADIOS SUBSEQUENTLY FAILED. WE LINED UP ON RWY 4R AND LANDED WITH NO RADIOS. WE EXITED RWY 4R AND SHUT DOWN THE ENGS. ARPT OPS AND FIRE RESCUE RESPONDED TO OUR LOCATION AND AFTER AN INITIAL DISCUSSION AND SAFETY INSPECTION; CALLED THE FBO TO TOW THE ACFT. AFTER NUMEROUS CONVERSATIONS WITH SEVERAL DIFFERENT MECHANICS; THE PREVAILING THEORY FOR THE TOTAL ELECTRICAL FAILURE WAS THE 'COLD START - FLIGHT NORMAL - GROUND POWER' SWITCH MAY HAVE BEEN INADVERTENTLY BUMPED INTO THE 'COLD START' POSITION WHICH WOULD HAVE PLACED THE BATTERIES IN A SERIES VS PARALLEL POSITION AND HAVE POSSIBLY CAUSED AN OVER VOLTAGE SITUATION WHICH WOULD HAVE TRIPPED BOTH GENERATORS OFF LINE AS WELL AS DRAINED THE BATTERIES. BOTH BATTERIES WERE SUBSEQUENTLY PULLED FROM THE ACFT FOR TESTING AND RECHARGING. IN CLOSELY EXAMINING THE ABOVE MENTIONED 3-WAY SWITCH; IT IS APPARENT THAT IT WOULD BE VERY EASY TO INADVERTENTLY MOVE THIS SWITCH OUT OF THE 'FLT NORMAL' POSITION AND INTO THE 'COLD START' POSITION. GIVEN THE SIGNIFICANT NEGATIVE IMPACT TO THE ELECTRICAL SYSTEM IF THIS HAPPENS; IT IS MY OPINION THAT THIS SWITCH SHOULD BE GUARDED IN SOME MANNER IN ORDER TO PREVENT THIS TYPE OF OCCURRENCE.CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED THAT THE ELECTRICAL POWER CTL SWITCH IS LOCATED ON THE OVERHEAD PANEL IN THE COCKPIT AND HAS THREE POSITIONS: GPU (ISOLATES THE BATTERIES FOR GND POWER USE); FLT NORMAL (PLACES THE BATTERIES IN PARALLEL AND LETS THE GENERATORS SUPPLY NORMAL POWER); COLD START (PLACES THE BATTERIES IN SERIES FOR EXTRA VOLTAGE TO START A COLD ENG). IN THE COLD START POSITION THE BATTERY VOLTAGE SUPPLIED IS DOUBLED AND THIS CAUSED THE OVER VOLTAGE TRIPPING THE GENERATOR. WHEN QUERIED REGARDING A 'LOSS OF ELECTRIC POWER' CHKLIST; THE RPTR STATED THAT THERE WAS A LOW CEILING AND WITH THE LOSS OF THE PRIMARY INSTRUMENTS THE FLT CREW FELT THERE WAS NOT TIME TO READ THE CHKLIST AND MAINTAIN VISUAL REFERENCE FOR LNDG. THEIR PRIMARY OBJECTIVE WAS TO GET THE ACFT ON THE GND. HE STATED THAT BY THE TIME THEY RETURNED FOR LNDG AND TOUCHED DOWN; THE ACFT WAS COMPLETELY DARK WITH NO LIGHTS ON IN THE COCKPIT; THERE WAS TOTAL ELECTRICAL POWER LOSS. HE INDICATED THAT THERE IS NO PLACE ON THE LINEUP OR TAXI CHKLIST THAT MENTIONS THIS SWITCH. ALSO; THERE IS NO WARNING LIGHT THAT WOULD INDICATE THE POSITION OF THE SWITCH TO THE FLT CREW. HE STATED THAT THE LOCAL FAA REPRESENTATIVE; AFTER REVIEWING THE INCIDENT; SUGGESTED THAT THE SWITCH POSITION BE PLACED ON THE LINEUP CHKLIST. ADDITIONALLY THE RPTR SUGGESTED THAT THE SWITCH BE GUARDED.

Data retrieved from NASA's ASRS site as of January 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.