Narrative:

I was repositioning aircraft X from ZZZ to ZZZ1. I departed on runway xx after obtaining clearance. I was cleared to 3000 ft. Before needing to contact center. I contacted center on my climb and was cleared to FL230.a couple of minutes into the climb the plane started to nose down. The autopilot turned off when that occurred. I had to apply excessive back pressure with both hands to keep the plane level and control altitude with power. I turned on the autopilot again to see if the nose down attitude would correct. After that failed; I tried the trim override but to no success.I was unable to run the QRH or pull the circuit breaker to the trim system; because if I let pressure off slightly the plane was nose diving. I finally [requested priority handling] and asked for vectors back to ZZZ. The controller was vectoring me back to runway xy and asked if I wanted to do the ILS. I declined and asked for vectors for runway xz knowing I needed the vertical guidance from the PAPI because I would be unable to program the GPS for the approach due to the consistent full force back pressure needed to maintain control.as I was fighting the nose down pressure I also needed to slow the plane down to land. I dropped the landing gear for extra drag but was still fast. I then oversped the flaps and dropped them to 15 degrees. Once I knew I would make the airport; I oversped the flaps again and dropped them to 30 degrees. This slowed the plane down into the white arch and I was able to land the plane 30 knots over vref safely on rwy xz in ZZZ.this aircraft was written up by multiple pilots for similar issues approximately 8 times. Quick flight checks were made after maintenance looked at it but; the problem persisted. The plane was released back to the line after each event.

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Original NASA ASRS Text

Title: PC12 Captain reported flight control malfunction in flight.

Narrative: I was repositioning Aircraft X from ZZZ to ZZZ1. I departed on Runway XX after obtaining clearance. I was cleared to 3000 ft. before needing to contact Center. I contacted Center on my climb and was cleared to FL230.A couple of minutes into the climb the plane started to nose down. The autopilot turned off when that occurred. I had to apply excessive back pressure with both hands to keep the plane level and control altitude with power. I turned on the autopilot again to see if the nose down attitude would correct. After that failed; I tried the trim override but to no success.I was unable to run the QRH or pull the circuit breaker to the trim system; because if I let pressure off slightly the plane was nose diving. I finally [requested priority handling] and asked for vectors back to ZZZ. The controller was vectoring me back to Runway XY and asked if I wanted to do the ILS. I declined and asked for vectors for runway XZ knowing I needed the vertical guidance from the PAPI because I would be unable to program the GPS for the approach due to the consistent full force back pressure needed to maintain control.As I was fighting the nose down pressure I also needed to slow the plane down to land. I dropped the landing gear for extra drag but was still fast. I then oversped the flaps and dropped them to 15 degrees. Once I knew I would make the airport; I oversped the flaps again and dropped them to 30 degrees. This slowed the plane down into the white arch and I was able to land the plane 30 knots over Vref safely on Rwy XZ in ZZZ.This aircraft was written up by multiple pilots for similar issues approximately 8 times. Quick flight checks were made after maintenance looked at it but; the problem persisted. The plane was released back to the line after each event.

Data retrieved from NASA's ASRS site 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.