Date: 201710
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Daylight
Aircraft: PC-12
Operator: Air Taxi
Operating under: Part 135
Flight plan: VFR
Mission: Passenger
Flight phase: Descent
ATC / advisory: Tower ZZZ
Aircraft component: Trailing Edge Flap
Component problem: Malfunctioning
Reporter organization: Air Taxi
Reporter function: Captain; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Flight Instructor; Flight Crew Multiengine; Flight Crew Instrument
Human factors: Confusion; Situational Awareness
Anomaly: Aircraft Equipment Problem Less Severe
Detector: Person Flight Crew
When detected: In-flight
Result: General Maintenance Action
Contributing factors: Aircraft; Human Factors
Primary problem: Aircraft

Narrative: Takeoff and cruise were normal and we descended into [destination]. While on the descent and within profile; my First Officer (Pilot Flying) called for flaps 15. We both noticed a loud bang noise and a shudder/shake of the airplane. We determined it had come from the left wing area. We didn't have any CAS message nor any abnormal flight forces associated with the noise and shudder. We looked over our airplane as best we could while airborne and determined that we had positive control and nothing looked wrong on the outside. We decided to lower flaps to 30 to see if our flaps worked fine. Nothing abnormal was noticed. We landed and had no further incident. Once engine shutdown and chocked; the First Officer and I decided to look over the aircraft to see if we maybe had a bird strike; drone strike; or any other factor that could cause such an event. We lowered and raised the flaps and both of us noticed no abnormalities. We also looked around the flaps and still didn't see anything out of the ordinary. I decided to continue with flight [to the next destination] as I couldn't find anything wrong.We had a flaps 15 takeoff. When I called for flaps up; we once again felt the shudder/shake from the left wing area. Since flaps were at 0 degrees and no CAS or any other abnormalities; I discussed our next move with my First Officer and we both decided to continue to [destination]. If any other abnormalities were to happen; we would [advise ATC] and land [at a suitable airport]. I was absolutely positive that we were 100% safe with our decision to continue the flight. We approached [destination] and I asked for flaps 15. Again; my First Officer and I noticed a very faint shudder/shake but nothing alarming. Again; no CAS or uncommanded aerodynamic forces were experienced. We lowered the flaps to 30 with no further problem and the landing was made safely. I decided to leave the flaps down at 30 degrees to once again find what was causing the shudder/shake. It was then that my First Officer found that our left flap center extension/retraction rod had snapped in two. I called Maintenance Control and Dispatch and the plane was grounded immediately.




Synopsis: PC-12 Captain reported continuing flight to the destination after experiencing shudder during flap extension where no damage was found. Upon landing after the subsequent flight they found that the left flap extend/retract rod had failed.