Narrative:

During descent I had the aircraft on autoplt. Around FL250 and 290 KTS the aircraft's left wing dipped quickly. The aircraft then sharply rolled right. I grasped the yoke firmly simultaneously disconnected autoplt. I corrected by the time we reached 30 degree roll. When I rolled level, I saw we had a left flight spoiler caution. No other problems the rest of the flight. Caution remained on. On ground, (in ZZZ) ZZZ1 maintenance (on phone) asked us to pull circuit breakers. We reset them and discrepancy cleared. ZZZ1 mx did not think it was necessary to send a mechanic. In flight, I think the left spoiler came up causing the left wing to drop. Then the autoplt tried to fight it by rolling right. Another crew would fly the aircraft the next day where maintenance would check it at the next station. Callback conversation with reporter revealed the following information: the reporter stated the aircraft was a canadair cl-65 and the cause of the left spoiler deployment was a flight spoiler power control unit. The reporter said the sharp right roll was the autoplt correction for the left wing dipping. The reporter stated the autoplt was disconnected and the airplane was flown manually with no problems. The reporter said the left flight spoiler warning light was on continuously until on the ground with maintenance control approval the circuit breaker was reset and cancelled the light.

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Original NASA ASRS Text

Title: A CANADAIR CL-65 ON DSCNT AT FL250,290 KNOTS HAD LEFT FLT SPOILER DEPLOY CAUSING QUICK L WING DIP. THEN SUDDEN SHARP R ROLL.

Narrative: DURING DSCNT I HAD THE ACFT ON AUTOPLT. AROUND FL250 AND 290 KTS THE ACFT'S LEFT WING DIPPED QUICKLY. THE ACFT THEN SHARPLY ROLLED RIGHT. I GRASPED THE YOKE FIRMLY SIMULTANEOUSLY DISCONNECTED AUTOPLT. I CORRECTED BY THE TIME WE REACHED 30 DEG ROLL. WHEN I ROLLED LEVEL, I SAW WE HAD A L FLT SPOILER CAUTION. NO OTHER PROBLEMS THE REST OF THE FLT. CAUTION REMAINED ON. ON GND, (IN ZZZ) ZZZ1 MAINT (ON PHONE) ASKED US TO PULL CIRCUIT BREAKERS. WE RESET THEM AND DISCREPANCY CLRED. ZZZ1 MX DID NOT THINK IT WAS NECESSARY TO SEND A MECH. IN FLT, I THINK THE LEFT SPOILER CAME UP CAUSING THE LEFT WING TO DROP. THEN THE AUTOPLT TRIED TO FIGHT IT BY ROLLING RIGHT. ANOTHER CREW WOULD FLY THE ACFT THE NEXT DAY WHERE MAINT WOULD CHECK IT AT THE NEXT STATION. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE ACFT WAS A CANADAIR CL-65 AND THE CAUSE OF THE LEFT SPOILER DEPLOYMENT WAS A FLT SPOILER POWER CTL UNIT. THE RPTR SAID THE SHARP RIGHT ROLL WAS THE AUTOPLT CORRECTION FOR THE LEFT WING DIPPING. THE RPTR STATED THE AUTOPLT WAS DISCONNECTED AND THE AIRPLANE WAS FLOWN MANUALLY WITH NO PROBS. THE RPTR SAID THE L FLT SPOILER WARNING LIGHT WAS ON CONTINUOUSLY UNTIL ON THE GND WITH MAINT CTL APPROVAL THE CB WAS RESET AND CANCELLED THE LIGHT.

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.