Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Workload; Human-Machine Interface; Troubleshooting
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Loss Of Aircraft Control
Air Traffic Control Provided Assistance; Flight Crew Became Reoriented; Flight Crew Overcame Equipment Problem; Flight Crew Returned To Departure Airport; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Regained Aircraft Control; General Flight Cancelled / Delayed; General Maintenance Action
Aircraft; Human Factors; Procedure
Immediately after takeoff; the horizontal trim failed. Neither pilot could activate the electric trim. The manual trim wheels were used to keep the aircraft in a trimmed condition; though with a significant amount of difficulty possibly due to the trim motor clutching against the manual inputs. The Stabilizer Trim Inoperative QRH procedures were followed.  [We advised ATC] and the flight returned to ZZZ for an uneventful flaps 15 landing.I don't know why the electric horizontal trim failed. I do know that the manual trim was significantly more difficult to operate during this event than it had been in previous instances where I've had to use the manual trim wheels. The aircraft was never too far out of trimmed condition; but a strong binding was felt as we rotated the trim wheels. It was suggested to me after the event that this binding sensation was in fact the trim motor 'clutching' against the manual inputs.  I'm not a strongman; but I worry that two smaller; weaker pilots might have found themselves in extremis.Figure out why the manual trim wheels felt as if they were binding; and correct that design condition.
Everything that occurred prior to the time we became aware of the Stab trim failure was normal and uneventful. Shortly after Takeoff; the Captain said his stab trim didn't seem to be working and asked me to check mine.  My stab trim was also inoperative. There were no other secondary issues. We continued with the departure while reviewing/going through the Stabilizer Trim Inoperative procedure. Once we had gone through the QRH procedure; we [advised ATC] and returned uneventfully to ZZZ where we wrote up the problem. We were given a new airplane about an hour later and continued our trip to ZZZ1. Cause; unknown maintenance issue.
Flight crew reported horizontal trim became inoperative with binding when attempting to use manual trim wheels. Flight crew elected to perform an air turn back.