PA-28 Cherokee/Archer/Dakota/Pillan/Warrior
Flight Crew Commercial; Flight Crew Flight Instructor; Flight Crew Instrument; Flight Crew Multiengine
Flight Crew Last 90 Days 294; Flight Crew Total 780.8; Flight Crew Type 190
Aircraft Equipment Problem Critical
General Maintenance Action
Aircraft
I was the flight instructor for the flight; flying with my student. It was a normal flight to review some of the lessons and maneuvers with my student. After having completed all the required maneuvers for that lesson for the flight; I asked my student to climb back up again to do one last Power-On stall for consistency before returning back to [the airport]. He completed the maneuver and then recovered from the stall normally. On the recovery; I saw him pitching up for Vy pitch attitude as required. He then seemed to be struggling a bit with the yoke before he told me that he could not pitch down any further. At that point I immediately took over the controls by saying my controls and I found out that I could not push any more forward on the yoke. At that point; because of the power settings being set to full power; the pitch attitude was increasing more upwards due to the increase in airspeed and the airplane being trimmed for about 60-65 knots for the entry of the maneuver. I immediately trimmed the airplane to lower the nose and to prevent it from stalling. After getting back to cruise; I checked the stabilator and it appeared to be stuck in what seemed to be slightly higher than nose level pitch attitude at about 100 knots airspeed. Pulling back on the yoke was not a problem; the issue was pushing forward. It felt like something was there that prevented the stabilator from moving down. After checking the GPS for distance; I saw that we were about 8 nautical miles southwest of the airport. I then immediately contacted the Tower; and requested a full stop. The Tower asked me if I needed assistance but I said no we did not. I did not declare an emergency as I had the airplane under control and I was still able to pitch down and up. On the way back to the airport; I checked the ailerons too and they seemed to be fine. I also looked back at the stabilator to try to see if we hit a bird or anything in-flight but from where I was looking; nothing abnormal was to be seen. About 10 minutes later I landed the airplane normally and then parked the airplane. After getting out I checked the stabilator again by trying to deflect the yoke forward and back but it had the same problem. I also looked at the tail section but could not see anything abnormal. I squawked the airplane as per normal procedure.
Reporter indicated that maintenance personnel had identified interference between the control yoke and a fuel line under the instrument panel. The subject flexible line was replaced by a rigid line to prevent this interference.
A Flight Instructor observed his student pilot struggle with the pitch control following recovery from a power-on stall. He assumed control of the aircraft and confirmed that he could not pitch down normally. He was able to adjust the trim and perform a normal landing. Maintenance personnel later identified interference between the control yoke and a fuel line under the instrument panel. The subject flexible line was replaced by a rigid line to prevent this interference.