Narrative:

In the first trip around the pattern; the already-soloed student was having some difficulties with aircraft control. By the third pattern; I took over the aircraft on the downwind to allow the student to relax and listen to my instruction. I found the aircraft out of trim; and re-trimmed it. We had a previous squawk where the electric-only trim had been slow to start; but the mechanics could not duplicate nor find the problem. I thought the problem might have recurred; but the trim ran fine. A few patterns later; the student was having difficulties again; so I ended up taking over the flight controls at 5 ft AGL; and decided on a go around. The controls felt like they were out of roll trim again; so I re-trimmed. On the upwind; I tried to demonstrate what a sideslip should look and feel like. The aircraft did not respond appropriately. I attempted to over-control the rudder; to exaggerate the rudder needed for the turn to crosswind. The aircraft did not want to turn right. I had been tired. I was now wide-awake. This is a fingertip control aircraft. I needed both hands and all of my strength on the side stick to roll right. The aileron control was rapidly diminishing and the amount of force needed was rapidly increasing. I re-trimmed again on downwind while explaining what was going on to the student. I then gave the aircraft control back to the student as he is much stronger than myself. I thought that his already being on the controls would be safer as that would allow me to correct further aircraft malfunctions as an additional strength input instead of my trying to direct his inputs to compensate for anything I couldn't control. I never thought to declare an emergency; as by that time we'd already been cleared to land. We landed safely; taxied in; and the student and I spent an hour debriefing. I checked the flight controls on the ground; and found them difficult to move. There is a rudder-aileron interconnect. The rudders were difficult to move. The side-stick remained difficult to move. Once outside; the left aileron moved through its range with minimal resistance. The right aileron stopped at approximately half way through its upward travel. If we forced it; it did full travel. After the mechanics re-calibrated the rudder-aileron interconnect bungee and replaced the suspected part; the trim cartridge; we found several other problems. The left aileron pulley was not hitting its top stop pin; forcing the trim cartridge out of alignment. We found damage to the aileron actuator arm; the actuator arm bearing (on the pulley); and a bent drive shaft on the electric motor that drives the trim cartridge. The mechanics have surveyed other cirrus [aircraft] on the field and found 2 others with this same feel in the controls. Another service center surveyed their aircraft and found 3 with the same problem; of all different ages. The mechanics have notified the aircraft owners affected. In the process of finding the true problem in our airplane; the mechanics have installed the left aileron incorrectly; mis-rigged the rudder-aileron interconnect; and unintentionally adjusted the right aileron fixed trim tab. Our school management sat them down and specifically instructed them to not rush and to take their time in this repair. Since that conversation; the mechanic errors have ceased and we continue to find more damaged parts. Callback conversation with reporter revealed the following information: the reporter stated the rudder and ailerons are interconnected; but the rudder trim is driven by an electric motor. In troubleshooting the system; a number of things were found: the trim cartridge was replaced. The left aileron pulley was not hitting the top stop pin forcing the trim cartridge out of alignment. Found damage to the aileron actuator arm; the arm bearing; and a bent drive shaft on the electric motor that drives the trim cartridge.

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Original NASA ASRS Text

Title: A CIRRUS SR20 ACFT OWNED AND OPERATED BY A FLT SCHOOL RPT AILERON AND RUDDER TRIM PROBS. ALSO FOUND ON 2 MORE CIRRUS SR20 ACFT.

Narrative: IN THE FIRST TRIP AROUND THE PATTERN; THE ALREADY-SOLOED STUDENT WAS HAVING SOME DIFFICULTIES WITH ACFT CTL. BY THE THIRD PATTERN; I TOOK OVER THE ACFT ON THE DOWNWIND TO ALLOW THE STUDENT TO RELAX AND LISTEN TO MY INSTRUCTION. I FOUND THE ACFT OUT OF TRIM; AND RE-TRIMMED IT. WE HAD A PREVIOUS SQUAWK WHERE THE ELECTRIC-ONLY TRIM HAD BEEN SLOW TO START; BUT THE MECHS COULD NOT DUPLICATE NOR FIND THE PROB. I THOUGHT THE PROB MIGHT HAVE RECURRED; BUT THE TRIM RAN FINE. A FEW PATTERNS LATER; THE STUDENT WAS HAVING DIFFICULTIES AGAIN; SO I ENDED UP TAKING OVER THE FLT CTLS AT 5 FT AGL; AND DECIDED ON A GAR. THE CTLS FELT LIKE THEY WERE OUT OF ROLL TRIM AGAIN; SO I RE-TRIMMED. ON THE UPWIND; I TRIED TO DEMONSTRATE WHAT A SIDESLIP SHOULD LOOK AND FEEL LIKE. THE ACFT DID NOT RESPOND APPROPRIATELY. I ATTEMPTED TO OVER-CTL THE RUDDER; TO EXAGGERATE THE RUDDER NEEDED FOR THE TURN TO XWIND. THE ACFT DID NOT WANT TO TURN R. I HAD BEEN TIRED. I WAS NOW WIDE-AWAKE. THIS IS A FINGERTIP CTL ACFT. I NEEDED BOTH HANDS AND ALL OF MY STRENGTH ON THE SIDE STICK TO ROLL R. THE AILERON CTL WAS RAPIDLY DIMINISHING AND THE AMOUNT OF FORCE NEEDED WAS RAPIDLY INCREASING. I RE-TRIMMED AGAIN ON DOWNWIND WHILE EXPLAINING WHAT WAS GOING ON TO THE STUDENT. I THEN GAVE THE ACFT CTL BACK TO THE STUDENT AS HE IS MUCH STRONGER THAN MYSELF. I THOUGHT THAT HIS ALREADY BEING ON THE CTLS WOULD BE SAFER AS THAT WOULD ALLOW ME TO CORRECT FURTHER ACFT MALFUNCTIONS AS AN ADDITIONAL STRENGTH INPUT INSTEAD OF MY TRYING TO DIRECT HIS INPUTS TO COMPENSATE FOR ANYTHING I COULDN'T CTL. I NEVER THOUGHT TO DECLARE AN EMER; AS BY THAT TIME WE'D ALREADY BEEN CLRED TO LAND. WE LANDED SAFELY; TAXIED IN; AND THE STUDENT AND I SPENT AN HR DEBRIEFING. I CHKED THE FLT CTLS ON THE GND; AND FOUND THEM DIFFICULT TO MOVE. THERE IS A RUDDER-AILERON INTERCONNECT. THE RUDDERS WERE DIFFICULT TO MOVE. THE SIDE-STICK REMAINED DIFFICULT TO MOVE. ONCE OUTSIDE; THE L AILERON MOVED THROUGH ITS RANGE WITH MINIMAL RESISTANCE. THE RIGHT AILERON STOPPED AT APPROXIMATELY HALF WAY THROUGH ITS UPWARD TRAVEL. IF WE FORCED IT; IT DID FULL TRAVEL. AFTER THE MECHS RE-CALIBRATED THE RUDDER-AILERON INTERCONNECT BUNGEE AND REPLACED THE SUSPECTED PART; THE TRIM CARTRIDGE; WE FOUND SEVERAL OTHER PROBS. THE L AILERON PULLEY WAS NOT HITTING ITS TOP STOP PIN; FORCING THE TRIM CARTRIDGE OUT OF ALIGNMENT. WE FOUND DAMAGE TO THE AILERON ACTUATOR ARM; THE ACTUATOR ARM BEARING (ON THE PULLEY); AND A BENT DRIVE SHAFT ON THE ELECTRIC MOTOR THAT DRIVES THE TRIM CARTRIDGE. THE MECHS HAVE SURVEYED OTHER CIRRUS [ACFT] ON THE FIELD AND FOUND 2 OTHERS WITH THIS SAME FEEL IN THE CTLS. ANOTHER SVC CTR SURVEYED THEIR ACFT AND FOUND 3 WITH THE SAME PROB; OF ALL DIFFERENT AGES. THE MECHS HAVE NOTIFIED THE ACFT OWNERS AFFECTED. IN THE PROCESS OF FINDING THE TRUE PROB IN OUR AIRPLANE; THE MECHS HAVE INSTALLED THE L AILERON INCORRECTLY; MIS-RIGGED THE RUDDER-AILERON INTERCONNECT; AND UNINTENTIONALLY ADJUSTED THE R AILERON FIXED TRIM TAB. OUR SCHOOL MGMNT SAT THEM DOWN AND SPECIFICALLY INSTRUCTED THEM TO NOT RUSH AND TO TAKE THEIR TIME IN THIS REPAIR. SINCE THAT CONVERSATION; THE MECH ERRORS HAVE CEASED AND WE CONTINUE TO FIND MORE DAMAGED PARTS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE RUDDER AND AILERONS ARE INTERCONNECTED; BUT THE RUDDER TRIM IS DRIVEN BY AN ELECTRIC MOTOR. IN TROUBLESHOOTING THE SYS; A NUMBER OF THINGS WERE FOUND: THE TRIM CARTRIDGE WAS REPLACED. THE L AILERON PULLEY WAS NOT HITTING THE TOP STOP PIN FORCING THE TRIM CARTRIDGE OUT OF ALIGNMENT. FOUND DAMAGE TO THE AILERON ACTUATOR ARM; THE ARM BEARING; AND A BENT DRIVE SHAFT ON THE ELECTRIC MOTOR THAT DRIVES THE TRIM CARTRIDGE.

Data retrieved from NASA's ASRS site as of January 2009 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.