N4970J

On June 7, 1996, at approximately 0530 mountain daylight time, a Cessna T188C, N4970J, operated by Lemmon Flying Service of Roundup, Montana, collided with terrain approximately 20 miles northeast of Roundup during a 14 CFR 137 agricultural aerial application flight. The single-seat restricted-category agricultural airplane was destroyed and its commercial pilot suffered serious injuries. Visual meteorological conditions prevailed and no flight plan had been filed for the local flight out of Roundup.

The pilot reported in a written statement to a FAA inspector: "Started with a missed G.P.S. approach and a turn out to the left to start a [different] approach. A drop in air [speed] in [first climbing] left turn and initiating second left turn at a lower than normal [airspeed] in [conjunction] with a [quartering] tail wind started a stall. I pushed it over to recover from stall and hit ground before I could pull up due to the low [altitude] at which I had turned." The T188C Information Manual lists power-off stall speeds for 4,400 pounds gross weight ranging from 67 MPH calibrated airspeed (at zero bank angle and 20 degrees flaps) to 100 MPH calibrated airspeed (at 60 degrees bank and flaps up), depending on bank angle and flap setting, and notes that altitude loss during stall recovery may be as much as 300 feet.

The airplane's shoulder harness attach ring broke during the accident sequence. According to a copy of the aircraft logbooks furnished by the operator, a new seat belt and shoulder harness were installed on the aircraft in April 1993 at 1,224.4 hours airframe total time (AFTT). Other aircraft maintenance documented with this April 1993 logbook entry included: "Replaced fuselage with like serviceable item, replaced both wings with [serviceable] rebuilt wings, replaced right elevator and trim tab, both flaps, vertical fin and horizontal stabilizer with repaired serviceable parts...." The seat and seat belts were documented as being checked during the aircraft's last annual inspection, performed on April 5, 1996 at 1,226.7 hours AFTT. The operator reported an AFTT of 1,336 hours at the time of the accident. Photographs of the fractured part showed that the two fracture faces were on a 45 degree plane to the direction of load on the part. The fractures were through two legs of the triangle, along a line parallel to the third leg (which anchors the harness strap.) The attach ring bolts to the airframe at the apex of the triangle, opposite the third leg. A photograph of the manufacture tag sewn to the seat belt indicated that the belt assembly had a rated strength of 1,500 pounds and conformed to FAA Technical Standard Order (TSO) C22f. The tag indicated that the belt was manufactured by Aero Fabricators of Lyons, Wisconsin, on January 4, 1993. FAA Advisory Circular (AC) 20-36S indicates that Aero Fabricators holds a TSO-C22f authorization to manufacture safety belts.