Narrative:

While parked at phl, an uncommanded brake release occurred on my aircraft. We had just completed the after start checklist, which was preceeded by signal for the marshallers to remove the nose gear chocks, then place the condition levers in the 'minimum' position (this action changes the propeller pitch from feather to a positive blade angle). My feet were on the pedals and I checked outside the aircraft as normally done. I then looked down for a moment in the cockpit. I felt a movement and looked up immediately at the control warning panel -- the parking brake light was illuminated, also witnessed by the first officer. We simultaneously applied brakes and the aircraft stopped. I pointed to the control warning panel light, he acknowledged it was on. I pointed to the brake handle, which he also acknowledged -- the handle was in the parked position. I tried moving it to reset it, it could not be moved, further indicating it was set. I tried to evaluate if I had previously misset the brake or in fact a mechanical problem existed. No injuries, no damage. We continued the flight to destination. The parking brake was set many times during this portion of the flight. No abnormalities.

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Original NASA ASRS Text

Title: SF34 CREW EXPERIENCES UNCOMMANDED PARKING BRAKE RELEASE AT PHL.

Narrative: WHILE PARKED AT PHL, AN UNCOMMANDED BRAKE RELEASE OCCURRED ON MY ACFT. WE HAD JUST COMPLETED THE AFTER START CHKLIST, WHICH WAS PRECEEDED BY SIGNAL FOR THE MARSHALLERS TO REMOVE THE NOSE GEAR CHOCKS, THEN PLACE THE CONDITION LEVERS IN THE 'MINIMUM' POS (THIS ACTION CHANGES THE PROP PITCH FROM FEATHER TO A POSITIVE BLADE ANGLE). MY FEET WERE ON THE PEDALS AND I CHKED OUTSIDE THE ACFT AS NORMALLY DONE. I THEN LOOKED DOWN FOR A MOMENT IN THE COCKPIT. I FELT A MOVEMENT AND LOOKED UP IMMEDIATELY AT THE CTL WARNING PANEL -- THE PARKING BRAKE LIGHT WAS ILLUMINATED, ALSO WITNESSED BY THE FO. WE SIMULTANEOUSLY APPLIED BRAKES AND THE ACFT STOPPED. I POINTED TO THE CTL WARNING PANEL LIGHT, HE ACKNOWLEDGED IT WAS ON. I POINTED TO THE BRAKE HANDLE, WHICH HE ALSO ACKNOWLEDGED -- THE HANDLE WAS IN THE PARKED POS. I TRIED MOVING IT TO RESET IT, IT COULD NOT BE MOVED, FURTHER INDICATING IT WAS SET. I TRIED TO EVALUATE IF I HAD PREVIOUSLY MISSET THE BRAKE OR IN FACT A MECHANICAL PROB EXISTED. NO INJURIES, NO DAMAGE. WE CONTINUED THE FLT TO DEST. THE PARKING BRAKE WAS SET MANY TIMES DURING THIS PORTION OF THE FLT. NO ABNORMALITIES.

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.