Narrative:

On june thu, 2000, I was accompanying mr. XXX wvwv on a flight from murfreesboro, tn to rockford, il when a malfunction of the autoplt trim system occurred. We were flying in his newly purchased merlin IIIA. He had just taken delivery of this aircraft the previous week. Mr. XXX wvwv had received his initial flight training from abc cde several months previous to this incident and I was accompanying him to give him additional training. The purpose of this trip was to fly to rockford and correct some miss rigging that I noted when the power levers were moved from flight idle toward reverse after landing the aircraft. We were cleared to an assigned altitude and upon reaching that altitude, I noted and commented to him that we had not leveled off. XXX wvwv who was controlling the aircraft with the autoplt, stated that something was wrong and the that the aircraft was not responding to his command. Suddenly, the aircraft went into an extreme nose over dive and I experienced extreme pressure against my seat belt. I grabbed my control wheel and attempted to disengage the autoplt but was unable to do so. I had both hands on the control wheel and exerted every bit of strength I could muster to pull the aircraft out of its dive. At this point, I am not sure if it was XXX wvwv or myself that was able to disconnect the nonessential bus, but in any case, it was disconnected and we finally gained control of the aircraft. Once control had been reestablished, we requested a return to murfreesboro for landing. The return and landing were uneventful. We received a ferry permit, disabled the autoplt, and flew the aircraft to maintenance. This whole episode took only a few seconds. I was informed later that the radar track indicated that we lost 600 ft in 3 seconds. Callback conversation with reporter revealed the following information: the reporter stated the hard over nose dive and inability to disconnect was an electronic failure in the autoplt and stability augmentation system. The reporter said the only method to get this system to disconnect was pulling the nonessential bus circuit breaker which pwrs this system. The reporter said both crew members pulled with full strength on the control wheel but pulling the circuit breaker saved their lives. The reporter stated the airplane was stored for a long period of time before being sold to mr. Wvwv.

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Original NASA ASRS Text

Title: A MERLIN III. AT 4000 FT THE CREW DISCOVERED NO AUTOPLT CTL TO LEVEL THE ACFT WHEN SUDDENLY THE ACFT WENT INTO AN EXTREME NOSE OVER DIVE.

Narrative: ON JUNE THU, 2000, I WAS ACCOMPANYING MR. XXX WVWV ON A FLT FROM MURFREESBORO, TN TO ROCKFORD, IL WHEN A MALFUNCTION OF THE AUTOPLT TRIM SYSTEM OCCURRED. WE WERE FLYING IN HIS NEWLY PURCHASED MERLIN IIIA. HE HAD JUST TAKEN DELIVERY OF THIS ACFT THE PREVIOUS WEEK. MR. XXX WVWV HAD RECEIVED HIS INITIAL FLT TRAINING FROM ABC CDE SEVERAL MONTHS PREVIOUS TO THIS INCIDENT AND I WAS ACCOMPANYING HIM TO GIVE HIM ADDITIONAL TRAINING. THE PURPOSE OF THIS TRIP WAS TO FLY TO ROCKFORD AND CORRECT SOME MISS RIGGING THAT I NOTED WHEN THE PWR LEVERS WERE MOVED FROM FLT IDLE TOWARD REVERSE AFTER LNDG THE ACFT. WE WERE CLEARED TO AN ASSIGNED ALT AND UPON REACHING THAT ALT, I NOTED AND COMMENTED TO HIM THAT WE HAD NOT LEVELED OFF. XXX WVWV WHO WAS CONTROLLING THE ACFT WITH THE AUTOPLT, STATED THAT SOMETHING WAS WRONG AND THE THAT THE ACFT WAS NOT RESPONDING TO HIS COMMAND. SUDDENLY, THE ACFT WENT INTO AN EXTREME NOSE OVER DIVE AND I EXPERIENCED EXTREME PRESSURE AGAINST MY SEAT BELT. I GRABBED MY CTL WHEEL AND ATTEMPTED TO DISENGAGE THE AUTOPLT BUT WAS UNABLE TO DO SO. I HAD BOTH HANDS ON THE CTL WHEEL AND EXERTED EVERY BIT OF STRENGTH I COULD MUSTER TO PULL THE ACFT OUT OF ITS DIVE. AT THIS POINT, I AM NOT SURE IF IT WAS XXX WVWV OR MYSELF THAT WAS ABLE TO DISCONNECT THE NONESSENTIAL BUS, BUT IN ANY CASE, IT WAS DISCONNECTED AND WE FINALLY GAINED CTL OF THE ACFT. ONCE CTL HAD BEEN REESTABLISHED, WE REQUESTED A RETURN TO MURFREESBORO FOR LNDG. THE RETURN AND LNDG WERE UNEVENTFUL. WE RECEIVED A FERRY PERMIT, DISABLED THE AUTOPLT, AND FLEW THE ACFT TO MAINT. THIS WHOLE EPISODE TOOK ONLY A FEW SECONDS. I WAS INFORMED LATER THAT THE RADAR TRACK INDICATED THAT WE LOST 600 FT IN 3 SECONDS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE HARD OVER NOSE DIVE AND INABILITY TO DISCONNECT WAS AN ELECTRONIC FAILURE IN THE AUTOPLT AND STABILITY AUGMENTATION SYSTEM. THE RPTR SAID THE ONLY METHOD TO GET THIS SYSTEM TO DISCONNECT WAS PULLING THE NONESSENTIAL BUS CIRCUIT BREAKER WHICH PWRS THIS SYSTEM. THE RPTR SAID BOTH CREW MEMBERS PULLED WITH FULL STRENGTH ON THE CTL WHEEL BUT PULLING THE CIRCUIT BREAKER SAVED THEIR LIVES. THE RPTR STATED THE AIRPLANE WAS STORED FOR A LONG PERIOD OF TIME BEFORE BEING SOLD TO MR. WVWV.

Data retrieved from NASA's ASRS site as of July 2007 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.