Narrative:

On climb out en route in IMC icing conditions; I as pilot flying noticed lights out of the corner of my eye. Looking up I realized that almost all the light on the overhead panel where illuminated as if a lamps test was in progress. I notified that captain of the situation immediately. I took control of communication with ATC and continued to act as pilot flying. The captain called dispatch and maintenance control. During the conversation with maintenance control the ice protection caution light illuminated on the central warning panel (cwp). Since we were in icing conditions and where picking up ice we decided to turn back and land at our departure airport. When conferred with maintenance control that there was nothing we could do to fix it in the air and there where no procedure in any of our manuals. We chose to return because we where less then 40nm away from the airport at that time; know the weather condition including the location of the freezing layer in the area; had the current surface observation; and still had quick and easy access to all information. I contacted center who we were with at the time and notified them that we needed to go back to for a precautionary landing. We where immediately given a vector for the ILS runway 8 and I requested a lower altitude where there was no icing. The captain notified dispatch of our return and contacted operations so that there were expecting us. He then notified that flight attendant that we where returning to the departure airport but that it was not an emergency. At the same time I clarified with center that we where not declaring an emergency and did not at the time need any special considerations. We soon exited the icing conditions. The captain took back communication with ATC and we completed all checks for our arrival and landed uneventfully. On arrival the captain notified the passengers that we had returned for a non-emergency maintenance problem and apologized for the delay that it would cause. We then taxied and disembarked the aircraft uneventfully. The event occurred from a electrical problem with the aircraft which had recently completed an inspection from maintenance. On the ground maintenance told us that they thought it was a problem with the warning computer. They replaced this computer but it did not solve the problem. The maintenance crew informed us that they had no idea what it was that caused it. The lack of a procedure or experience with problem led to us making a precautionary landing. I see this as a random failure of the system indication controls that could not be prevented. As the aircraft had recently come out of inspection and had successfully completed all first flight of the day tests.

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Original NASA ASRS Text

Title: A SF340 overhead panel light warning system malfunction caused the overhead warning lights to illuminate. In icing conditions and uncertain about the aircraft's status; the crew returned to land at the departure airport.

Narrative: On climb out en route in IMC Icing conditions; I as pilot flying noticed lights out of the corner of my eye. Looking up I realized that almost all the light on the overhead panel where illuminated as if a lamps test was in progress. I notified that Captain of the situation immediately. I took control of communication with ATC and continued to act as Pilot Flying. The Captain called Dispatch and Maintenance control. During the conversation with Maintenance Control the Ice Protection caution light illuminated on the Central Warning Panel (CWP). Since we were in icing conditions and where picking up ice we decided to turn back and land at our departure airport. When conferred with Maintenance Control that there was nothing we could do to fix it in the air and there where no procedure in any of our manuals. We chose to return because we where less then 40nm away from the airport at that time; know the weather condition including the location of the freezing layer in the area; had the current surface observation; and still had quick and easy access to all information. I contacted Center who we were with at the time and notified them that we needed to go back to for a precautionary landing. We where immediately given a vector for the ILS Runway 8 and I requested a lower altitude where there was no icing. The Captain notified Dispatch of our return and contacted Operations so that there were expecting us. He then notified that Flight Attendant that we where returning to the departure airport but that it was not an emergency. At the same time I clarified with Center that we where not declaring an emergency and did not at the time need any special considerations. We soon exited the icing conditions. The Captain took back communication with ATC and we completed all checks for our arrival and landed uneventfully. On arrival the Captain notified the passengers that we had returned for a non-emergency maintenance problem and apologized for the delay that it would cause. We then taxied and disembarked the aircraft uneventfully. The event occurred from a electrical problem with the aircraft which had recently completed an inspection from Maintenance. On the ground Maintenance told us that they thought it was a problem with the warning computer. They replaced this computer but it did not solve the problem. The Maintenance Crew informed us that they had no idea what it was that caused it. The lack of a procedure or experience with problem led to us making a precautionary landing. I see this as a random failure of the system indication controls that could not be prevented. As the aircraft had recently come out of inspection and had successfully completed all first flight of the day tests.

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.