What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
Aircraft ground looped on landing. Pilot reported that on final approach an abnormality developed when releasing the auto pilot by pressing the red ap disc button on the top of the control stick. The airplane yawed to the right, almost full ball deflection. Correcting this yaw with left rudder was effective to ball center. He did not notice any rudder abnormalities once the yaw damper released. He re-engaged the yaw damper and rudder control was normal. On final he released the yaw damper but and rudder control seemed normal. He slipped the aircraft to the left using right rudder and cross control left aileron. Upon taking out the slip on short final, he reported that he could not get left rudder input. His left foot was all the way to the floor and the aircraft nose was still tracking to the right. Rather than go around with a flight control problem, he elected to land in a nose right crab. Upon touch down just after the stall horn tounded the aircraft wanted to go right and he could not get any rudder effectiveness with the peddle fully depressed to the floor. The aircraft veered to the right, crossed over the asphalt runway.
Pilot took photos of auto pilot installed in January 2020, privacy data omitted, indicated the yaw damper servo cable was lose. He believes the excessive slack in the rudder servo bridle cable possibly caused by a loose bridle cable clamp allowed the bridle cable to slip under the pulley bracket and jam. Photo shows that there was no cotter pin in the hole next to the pulley assembly, (part MS24665-136) as shown on privacy data omitted install drawing 190-02291-38 rev 3, sheet 14 of 20. He believe that the cotter pin if installed, could have prevented the cable from sliding under the pulley bracket.
Aircraft had been returned to manufacturer and investigation continues to confirm pilots theory of accident. NTSB and FAA continues investigation concerning auto pilot installation. Repair station who installed autopilot has been sent information and is participating in investigation. This report will be amended if further conculsions or actions are taken.
As the FAA filed it
AIRCRAFT GROUND LOOPED ON LANDING. PILOT REPORTED THAT ON FINAL APPROACH AN ABNORMALITY DEVELOPED WHEN RELEASING THE AUTO PILOT BY PRESSING THE RED AP DISC BUTTON ON THE TOP OF THE CONTROL STICK. THE AIRPLANE YAWED TO THE RIGHT, ALMOST FULL BALL DEFLECTION. CORRECTING THIS YAW WITH LEFT RUDDER WAS EFFECTIVE TO BALL CENTER. HE DID NOT NOTICE ANY RUDDER ABNORMALITIES ONCE THE YAW DAMPER RELEASED. HE RE-ENGAGED THE YAW DAMPER AND RUDDER CONTROL WAS NORMAL. ON FINAL HE RELEASED THE YAW DAMPER BUT AND RUDDER CONTROL SEEMED NORMAL. HE SLIPPED THE AIRCRAFT TO THE LEFT USING RIGHT RUDDER AND CROSS CONTROL LEFT AILERON. UPON TAKING OUT THE SLIP ON SHORT FINAL, HE REPORTED THAT HE COULD NOT GET LEFT RUDDER INPUT. HIS LEFT FOOT WAS ALL THE WAY TO THE FLOOR AND THE AIRCRAFT NOSE WAS STILL TRACKING TO THE RIGHT. RATHER THAN GO AROUND WITH A FLIGHT CONTROL PROBLEM, HE ELECTED TO LAND IN A NOSE RIGHT CRAB. UPON TOUCH DOWN JUST AFTER THE STALL HORN TOUNDED THE AIRCRAFT WANTED TO GO RIGHT AND HE COULD NOT GET ANY RUDDER EFFECTIVENESS WITH THE PEDDLE FULLY DEPRESSED TO THE FLOOR. THE AIRCRAFT VEERED TO THE RIGHT, CROSSED OVER THE ASPHALT RUNWAY.
PILOT TOOK PHOTOS OF AUTO PILOT INSTALLED IN JANUARY 2020, ^PRIVACY DATA OMITTED^, INDICATED THE YAW DAMPER SERVO CABLE WAS LOSE. HE BELIEVES THE EXCESSIVE SLACK IN THE RUDDER SERVO BRIDLE CABLE POSSIBLY CAUSED BY A LOOSE BRIDLE CABLE CLAMP ALLOWED THE BRIDLE CABLE TO SLIP UNDER THE PULLEY BRACKET AND JAM. PHOTO SHOWS THAT THERE WAS NO COTTER PIN IN THE HOLE NEXT TO THE PULLEY ASSEMBLY, (PART MS24665-136) AS SHOWN ON ^PRIVACY DATA OMITTED^ INSTALL DRAWING 190-02291-38 REV 3, SHEET 14 OF 20. HE BELIEVE THAT THE COTTER PIN IF INSTALLED, COULD HAVE PREVENTED THE CABLE FROM SLIDING UNDER THE PULLEY BRACKET.
AIRCRAFT HAD BEEN RETURNED TO MANUFACTURER AND INVESTIGATION CONTINUES TO CONFIRM PILOTS THEORY OF ACCIDENT. NTSB AND FAA CONTINUES INVESTIGATION CONCERNING AUTO PILOT INSTALLATION. REPAIR STATION WHO INSTALLED AUTOPILOT HAS BEEN SENT INFORMATION AND IS PARTICIPATING IN INVESTIGATION. THIS REPORT WILL BE AMENDED IF FURTHER CONCULSIONS OR ACTIONS ARE TAKEN.
NTSB investigation
The NTSB’s investigation of this event, with its probable cause and findings. Matched to this report by N-number and date.