What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
(-23) privacy data omitted entered the traffic pattern for runway 16 at the Moses Lake Municipal Airport (W20). Witnesses stated that the aircraft was pitching up erratically. During the approach the aircraft appeared to be high and the pilot slipped the aircraft to put it in a normal position for landing. privacy data omitted Observed the approach and advised privacy data omitted to go around on the radio. When the power came up the aircraft started a skidding left turn low across the airport. The aircraft preceded to a point under the normal traffic pattern for the airport where it continued making descending left turns. Four witnesses heard privacy data omitted say over the radio that he was having difficulty maintaining control of the aircraft. The aircraft made several left turns all the while in a slow descent. The aircraft crossed over some powerlines that run east and and west from the airport and just barely missing some tall trees. The aircraft was headed for a corn field when it pitch violently up then nosed down and crashed in the field. Investigation of the wreckage showed the attach points for the tail section of the aircraft had separated from the fuselage. The stubs that fit into the sockets that hold the tail on have stubs that bolts should go through. They had no holes through them. The sockets that the stubs fit into showed signs of wear. The aircraft had no airworthiness certificate and had not been inspected by the FAA or its representative. privacy data omitted Was the builder of the aircraft with the help of privacy data omitted. The tail section is secured by two attach points of post and socket style design, I.e. a tubular stub is secured in a tubular socket then a through-bolt is inserted through both pieces and secured with a bolt and self-locking nut. The bolt holes are predrilled in the socket but not in the tubular stub which must be drilled by the aircraft assembler. From paint signatures on the stubs and wear patterns in the sockets, it appears as if the stubs were not inserted deep enough into the sockets to block the predrilled bolt holes. Had the assembler properly inserted the undrilled stubs into the sockets he would not have been able to insert the bolts through the socket stub assembly. As it was, it appears that the bolt was inserted through the socket below the stub therefore prohibiting a positive lock. It also appears as though some pinching of the stub may have occurred as a result of tightening the through-bolt which may have presented the false indication to the assembler that the connection was secure when indeed it was not.
As the FAA filed it
(-23) ^PRIVACY DATA OMITTED^ ENTERED THE TRAFFIC PATTERN FOR RUNWAY 16 AT THE MOSES LAKE MUNICIPAL AIRPORT (W20). WITNESSES STATED THAT THE AIRCRAFT WAS PITCHING UP ERRATICALLY. DURING THE APPROACH THE AIRCRAFT APPEARED TO BE HIGH AND THE PILOT SLIPPED THE AIRCRAFT TO PUT IT IN A NORMAL POSITION FOR LANDING. ^PRIVACY DATA OMITTED^ OBSERVED THE APPROACH AND ADVISED ^PRIVACY DATA OMITTED^ TO GO AROUND ON THE RADIO. WHEN THE POWER CAME UP THE AIRCRAFT STARTED A SKIDDING LEFT TURN LOW ACROSS THE AIRPORT. THE AIRCRAFT PRECEDED TO A POINT UNDER THE NORMAL TRAFFIC PATTERN FOR THE AIRPORT WHERE IT CONTINUED MAKING DESCENDING LEFT TURNS. FOUR WITNESSES HEARD ^PRIVACY DATA OMITTED^ SAY OVER THE RADIO THAT HE WAS HAVING DIFFICULTY MAINTAINING CONTROL OF THE AIRCRAFT. THE AIRCRAFT MADE SEVERAL LEFT TURNS ALL THE WHILE IN A SLOW DESCENT. THE AIRCRAFT CROSSED OVER SOME POWERLINES THAT RUN EAST AND AND WEST FROM THE AIRPORT AND JUST BARELY MISSING SOME TALL TREES. THE AIRCRAFT WAS HEADED FOR A CORN FIELD WHEN IT PITCH VIOLENTLY UP THEN NOSED DOWN AND CRASHED IN THE FIELD. INVESTIGATION OF THE WRECKAGE SHOWED THE ATTACH POINTS FOR THE TAIL SECTION OF THE AIRCRAFT HAD SEPARATED FROM THE FUSELAGE. THE STUBS THAT FIT INTO THE SOCKETS THAT HOLD THE TAIL ON HAVE STUBS THAT BOLTS SHOULD GO THROUGH. THEY HAD NO HOLES THROUGH THEM. THE SOCKETS THAT THE STUBS FIT INTO SHOWED SIGNS OF WEAR. THE AIRCRAFT HAD NO AIRWORTHINESS CERTIFICATE AND HAD NOT BEEN INSPECTED BY THE FAA OR ITS REPRESENTATIVE. ^PRIVACY DATA OMITTED^ WAS THE BUILDER OF THE AIRCRAFT WITH THE HELP OF ^PRIVACY DATA OMITTED^. THE TAIL SECTION IS SECURED BY TWO ATTACH POINTS OF POST AND SOCKET STYLE DESIGN, I.E. A TUBULAR STUB IS SECURED IN A TUBULAR SOCKET THEN A THROUGH-BOLT IS INSERTED THROUGH BOTH PIECES AND SECURED WITH A BOLT AND SELF-LOCKING NUT. THE BOLT HOLES ARE PREDRILLED IN THE SOCKET BUT NOT IN THE TUBULAR STUB WHICH MUST BE DRILLED BY THE AIRCRAFT ASSEMBLER. FROM PAINT SIGNATURES ON THE STUBS AND WEAR PATTERNS IN THE SOCKETS, IT APPEARS AS IF THE STUBS WERE NOT INSERTED DEEP ENOUGH INTO THE SOCKETS TO BLOCK THE PREDRILLED BOLT HOLES. HAD THE ASSEMBLER PROPERLY INSERTED THE UNDRILLED STUBS INTO THE SOCKETS HE WOULD NOT HAVE BEEN ABLE TO INSERT THE BOLTS THROUGH THE SOCKET STUB ASSEMBLY. AS IT WAS, IT APPEARS THAT THE BOLT WAS INSERTED THROUGH THE SOCKET BELOW THE STUB THEREFORE PROHIBITING A POSITIVE LOCK. IT ALSO APPEARS AS THOUGH SOME PINCHING OF THE STUB MAY HAVE OCCURRED AS A RESULT OF TIGHTENING THE THROUGH-BOLT WHICH MAY HAVE PRESENTED THE FALSE INDICATION TO THE ASSEMBLER THAT THE CONNECTION WAS SECURE WHEN INDEED IT WAS NOT.
NTSB investigation
The NTSB’s investigation of this event, with its probable cause and findings. Matched to this report by N-number and date.