Date: 202101
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Flight conditions: VMC
Weather elements / visibility: 10
Light: Daylight
Aircraft: PA-28 Cherokee/Archer/Dakota/Pillan/Warrior
Operator: FBO
Operating under: Part 91
Flight plan: None
Mission: Training
Flight phase: Cruise
Airspace: Class G ZZZ
ATC / advisory: Tower ZZZ
Aircraft component: Autopilot
Component problem: Improperly Operated
Reporter organization: FBO
Reporter function: Instructor; Pilot Flying
Reporter qualification: Flight Crew Commercial; Flight Crew Flight Instructor; Flight Crew Instrument; Flight Crew Multiengine
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy; Flight Deck / Cabin / Aircraft Event Illness / Injury; Inflight Event / Encounter Loss Of Aircraft Control
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Provided Assistance; Flight Crew Became Reoriented; Flight Crew Landed in Emergency Condition; Flight Crew Overcame Equipment Problem; Flight Crew Returned To Departure Airport; General Maintenance Action
Contributing factors: Procedure; Aircraft
Primary problem: Procedure

Narrative: Finishing up a training flight with a student in Class G Airspace my student advised he was starting to feel nauseous. I took control of the aircraft from my student using the 3 part positive exchange of flight controls. As I took control of the aircraft I noticed the flight controls were extremely stiff on the longitudinal axis (ailerons). When asking the student if he was blocking the yoke from moving he responded with no and I visually confirmed he was nowhere near any of the controls. After maintaining positive control of the aircraft I started looking around both yokes for a reason why there was such an issue with the roll function as well as looking out at both ailerons. I could not find any reason why I was having such an issue maintaining level flight. We had just completed turns around a point and I wondered if a bird or something collided with the underside of the right aileron at just the correct time that prevented me from turning the yoke right or if there was something that caught up the control cables inside the wing that was preventing this. I was about 15 miles and a 180 degree turn from ZZZ1 and about 20 miles straight to ZZZ. I decided that ZZZ was not only straight ahead but 95% could be over water and wetlands versus ZZZ1 which would put me over populations and wooded areas for a majority of the flight as well as the services available at ZZZ (ATC; ARFF; Line services; Maintenance and the aircraft's Home base). The decision was made and I continued straight towards ZZZ and listened to the ATIS while having the student look through the Emergency Checklist for anything that listed flight control issues. I also verified that the elevators and rudder were not experiencing any issues. I attempted to go further to the right but was met with more and more resistance and did not want to risk snapping anything or causing any further issues/damage. I contacted the tower and advised I was approximately 20 miles south of the airport with some sort of flight control issue and requested a straight in priority landing on Runway 1. Flying straight I would have intercepted the extended centerline on a very shallow 10-15 degrees. Tower advised me to continue and expect the request as well as asked if I needed anything. I advised I did not and was trying to work the issue while maintaining in control. About 10 miles out I realized that while I was maintaining control at 107 KIAS I had no idea what the aircraft would do as I slowed to approach speed of 66 KIAS. I also noticed that I was applying a considerable amount of right rudder to maintain straight flight. At point I made the decision with the unknowns there and having to be uncoordinated as I would be approaching the ground I would prefer Fire Services standing by as well as identify as an emergency to open up any further options that could be available as I may only have 1 shot at the approach once I get down towards that 66 KIAS. I advised my student to tighten his seat belt and that my arms were starting to get tired holding the airplane level that I would need him to use CRM with me and help with Power settings and flaps. At about 1;000MSL I told my student that at 800AGL I wanted him to release the top latch of my door and by 500AGL I wanted him to release the side latch so the door could be unlocked and we can focus on landing in the last 500ft. As I crossed the threshold at about 80KIAS with 2 notches (25 degree) of flaps and about 5 degrees of intercept of the centerline I had my student reduce the power to idle and maintained control through landing but did end up left of centerline.After the aircraft was fully on the ground rolling out I released the yoke which went full deflection to the left. I taxied the aircraft back to the FBO apron and shut down the aircraft. I had my Senior CFI meet us to have him look for a possible issue. After the aircraft was completely shut down I had him go and try to move the yoke which he did with no issues. Further investigation it was noticed that the autopilot (AP); Single Axis; roll knob was turned to the left. The autopilot was never a thought as upon hiring over a year ago I was advised by the then-Assistant Chief Flight Instructor that the Auto pilot did not work; was disconnected from power but not able to be removed from the bottom of the panel. I never thought anything of it because during night flights the AP never had any backlighting to show it had power.  My senior instructor and I started up the aircraft and initiated the Autopilot which produced the same effect that I experienced in flight. We conducted a full check of all systems and found nothing else that could have caused the issue. We determined that the location of the AP the student could have inadvertently brushed the switch activating it with no knowledge as there are no lights to indicate it is powered or active. We also came to the conclusion that this incident was not a flight control malfunction as much as an unintentional activation of the AP as the AP did what it was told. Speaking with my Senior CFI we decided that I would personally verify any statements of inoperability from another pilot even if they are a superior with Maintenance and make sure the correct items are done for such items. I am also working on a full lesson for all of my students on the AP; how it works; issues experienced and multiple ways on how to shut it off until a decision could be made to keep the AP with it known active or make the AP inoperative and remove it from the aircraft.




Synopsis: Instructor reported the aircraft became hard to control; causing a return to home base and a precautionary emergency landing.