What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
(.4) The pilot reported that while flying in IMC, he was having difficulty with the autopilot. Specifically, he was having problems holding assigned headings, and engaging the autopilot. The airplane then began a rapid descent, but the pilot was able to recover once in VMC. Prior to the accident flight, the pilot experienced difficulty with another airplane. In that airplane, with a different model autopilot, he lost control while landing. According to representatives from the airplane and autopilot manufacturers, the pilot and owner complained about autopilot problems in the past. However, on at least two occasions prior to the accident flight, the owner or pilot of the airplane had been operating the autopilot while the airplane was outside the specifications for safe autopilot operation. Prior to the accident, three separate test flights did not reveal any malfunctions. After the accident, the pilot stated that he might have departed with the autopilot in the slaved nav heading disengaged mode. Subsequently, data retrieved from the autopilot did not indicate any malfunctions. (-23) FAA flight standards became aware of this accident by virtue of a hotline complaint that had been filed by the owner of the aircraft, privacy data omitted alleged that the manufacturer of the autopilot (Honeywell) was responsible for the damage to his aircraft which resulted from an uncommanded pitch damage which caused an uncontrolled descent. Investigation determined that the pilot, Mr. Normand paulhus, was on an instrument flight rules clearance and was allegedly experiencing difficulties in managing the autopilot. According to Mr. Paulhus, the aircraft suddenly pitched down and commended an uncontrolled descent. The pilot stated that he finally regained control when he entered visual conditions and was able to reference the ground. The aircraft received significant damage from what appears to have been in-flight stress as a result of exceeding design limits of the aircraft. Post-event testing of the aircraft and flight control system was conducted with Mr. Paulhus once agaain operating the autopilot. While mfgr's reps could find no apparent cause for the uncontrolled descent it was observed that during the post-event flight test Mr. Paulhus failed to follow the prescribed procedures.
As the FAA filed it
(.4) THE PILOT REPORTED THAT WHILE FLYING IN IMC, HE WAS HAVING DIFFICULTY WITH THE AUTOPILOT. SPECIFICALLY, HE WAS HAVING PROBLEMS HOLDING ASSIGNED HEADINGS, AND ENGAGING THE AUTOPILOT. THE AIRPLANE THEN BEGAN A RAPID DESCENT, BUT THE PILOT WAS ABLE TO RECOVER ONCE IN VMC. PRIOR TO THE ACCIDENT FLIGHT, THE PILOT EXPERIENCED DIFFICULTY WITH ANOTHER AIRPLANE. IN THAT AIRPLANE, WITH A DIFFERENT MODEL AUTOPILOT, HE LOST CONTROL WHILE LANDING. ACCORDING TO REPRESENTATIVES FROM THE AIRPLANE AND AUTOPILOT MANUFACTURERS, THE PILOT AND OWNER COMPLAINED ABOUT AUTOPILOT PROBLEMS IN THE PAST. HOWEVER, ON AT LEAST TWO OCCASIONS PRIOR TO THE ACCIDENT FLIGHT, THE OWNER OR PILOT OF THE AIRPLANE HAD BEEN OPERATING THE AUTOPILOT WHILE THE AIRPLANE WAS OUTSIDE THE SPECIFICATIONS FOR SAFE AUTOPILOT OPERATION. PRIOR TO THE ACCIDENT, THREE SEPARATE TEST FLIGHTS DID NOT REVEAL ANY MALFUNCTIONS. AFTER THE ACCIDENT, THE PILOT STATED THAT HE MIGHT HAVE DEPARTED WITH THE AUTOPILOT IN THE SLAVED NAV HEADING DISENGAGED MODE. SUBSEQUENTLY, DATA RETRIEVED FROM THE AUTOPILOT DID NOT INDICATE ANY MALFUNCTIONS. (-23) FAA FLIGHT STANDARDS BECAME AWARE OF THIS ACCIDENT BY VIRTUE OF A HOTLINE COMPLAINT THAT HAD BEEN FILED BY THE OWNER OF THE AIRCRAFT, ^PRIVACY DATA OMITTED^ ALLEGED THAT THE MANUFACTURER OF THE AUTOPILOT (HONEYWELL) WAS RESPONSIBLE FOR THE DAMAGE TO HIS AIRCRAFT WHICH RESULTED FROM AN UNCOMMANDED PITCH DAMAGE WHICH CAUSED AN UNCONTROLLED DESCENT. INVESTIGATION DETERMINED THAT THE PILOT, MR. NORMAND PAULHUS, WAS ON AN INSTRUMENT FLIGHT RULES CLEARANCE AND WAS ALLEGEDLY EXPERIENCING DIFFICULTIES IN MANAGING THE AUTOPILOT. ACCORDING TO MR. PAULHUS, THE AIRCRAFT SUDDENLY PITCHED DOWN AND COMMENDED AN UNCONTROLLED DESCENT. THE PILOT STATED THAT HE FINALLY REGAINED CONTROL WHEN HE ENTERED VISUAL CONDITIONS AND WAS ABLE TO REFERENCE THE GROUND. THE AIRCRAFT RECEIVED SIGNIFICANT DAMAGE FROM WHAT APPEARS TO HAVE BEEN IN-FLIGHT STRESS AS A RESULT OF EXCEEDING DESIGN LIMITS OF THE AIRCRAFT. POST-EVENT TESTING OF THE AIRCRAFT AND FLIGHT CONTROL SYSTEM WAS CONDUCTED WITH MR. PAULHUS ONCE AGAAIN OPERATING THE AUTOPILOT. WHILE MFGR'S REPS COULD FIND NO APPARENT CAUSE FOR THE UNCONTROLLED DESCENT IT WAS OBSERVED THAT DURING THE POST-EVENT FLIGHT TEST MR. PAULHUS FAILED TO FOLLOW THE PRESCRIBED PROCEDURES.
NTSB investigation
The NTSB’s investigation of this event, with its probable cause and findings. Matched to this report by N-number and date.