Narrative:

During the descent, the captain reached up to the overhead panel to switch on the landing lights. His fingers accidentally hit the electric autofeather switch on the left engine. The propeller immediately feathered. The power levers were at about 50% and the left torque jumped to 99% when the propeller feathered. I reduced the torque, disengaged the autoplt and took over the normal PNF duties while the captain reviewed the QRH to deal with the feathered propeller. I continued to set up the aircraft for an ILS into mfr. No procedure is in our QRH to deal with an 'accidental pilot induced feathering.' with the left power lever of flight idle the captain unfeathered the propeller and we continued to a normal landing. The aircraft was grounded until the flight data recorder could be checked to verify that the left engine did not overtorque. The captain was put on administrative leave until a line check could be done for him. I was told that this problem normally happens to new capts who FLIP switches too fast. This captain only had 2 hours since completing IOE. Callback conversation with reporter revealed the following information: the occurrence of accidental engine feathering has become of concern to this operator of the brasilia. The co-location of the autofeather arming, electric feather and landing light switches has resulted in several accidental and several near feathering of the left engine. Further, the location and direction of movement are such that the normal arm motion can raise the guard and activate the electric feather mechanism in a single motion. Supplemental information from acn 457862: during descent into mfr, I turned on the ice inspection lights and logo lights as specified in our SOP descent flow. My hand continued in an upward motion and accidentally unguarded and actuated the left electric feathering switch. Contributing factors include close proximity of left engine electric feathering switch to the light switches, also a poor guard design in which the guarded switch activates in the same direction as the guard, making it possible to unguard and actuate the switch in the same motion.

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Original NASA ASRS Text

Title: A NEW BRASILIA CAPT ACCIDENTALLY FEATHERS AN ENG WHILE ATTEMPTING TO TURN ON THE LNDG LIGHTS NEAR MFR.

Narrative: DURING THE DSCNT, THE CAPT REACHED UP TO THE OVERHEAD PANEL TO SWITCH ON THE LNDG LIGHTS. HIS FINGERS ACCIDENTALLY HIT THE ELECTRIC AUTOFEATHER SWITCH ON THE L ENG. THE PROP IMMEDIATELY FEATHERED. THE PWR LEVERS WERE AT ABOUT 50% AND THE L TORQUE JUMPED TO 99% WHEN THE PROP FEATHERED. I REDUCED THE TORQUE, DISENGAGED THE AUTOPLT AND TOOK OVER THE NORMAL PNF DUTIES WHILE THE CAPT REVIEWED THE QRH TO DEAL WITH THE FEATHERED PROP. I CONTINUED TO SET UP THE ACFT FOR AN ILS INTO MFR. NO PROC IS IN OUR QRH TO DEAL WITH AN 'ACCIDENTAL PLT INDUCED FEATHERING.' WITH THE L PWR LEVER OF FLT IDLE THE CAPT UNFEATHERED THE PROP AND WE CONTINUED TO A NORMAL LNDG. THE ACFT WAS GNDED UNTIL THE FLT DATA RECORDER COULD BE CHKED TO VERIFY THAT THE L ENG DID NOT OVERTORQUE. THE CAPT WAS PUT ON ADMINISTRATIVE LEAVE UNTIL A LINE CHK COULD BE DONE FOR HIM. I WAS TOLD THAT THIS PROB NORMALLY HAPPENS TO NEW CAPTS WHO FLIP SWITCHES TOO FAST. THIS CAPT ONLY HAD 2 HRS SINCE COMPLETING IOE. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE OCCURRENCE OF ACCIDENTAL ENG FEATHERING HAS BECOME OF CONCERN TO THIS OPERATOR OF THE BRASILIA. THE CO-LOCATION OF THE AUTOFEATHER ARMING, ELECTRIC FEATHER AND LNDG LIGHT SWITCHES HAS RESULTED IN SEVERAL ACCIDENTAL AND SEVERAL NEAR FEATHERING OF THE L ENG. FURTHER, THE LOCATION AND DIRECTION OF MOVEMENT ARE SUCH THAT THE NORMAL ARM MOTION CAN RAISE THE GUARD AND ACTIVATE THE ELECTRIC FEATHER MECHANISM IN A SINGLE MOTION. SUPPLEMENTAL INFO FROM ACN 457862: DURING DSCNT INTO MFR, I TURNED ON THE ICE INSPECTION LIGHTS AND LOGO LIGHTS AS SPECIFIED IN OUR SOP DSCNT FLOW. MY HAND CONTINUED IN AN UPWARD MOTION AND ACCIDENTALLY UNGUARDED AND ACTUATED THE L ELECTRIC FEATHERING SWITCH. CONTRIBUTING FACTORS INCLUDE CLOSE PROX OF L ENG ELECTRIC FEATHERING SWITCH TO THE LIGHT SWITCHES, ALSO A POOR GUARD DESIGN IN WHICH THE GUARDED SWITCH ACTIVATES IN THE SAME DIRECTION AS THE GUARD, MAKING IT POSSIBLE TO UNGUARD AND ACTUATE THE SWITCH IN THE SAME MOTION.

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.