WPR16FA002

A company chief pilot was performing a company check flight of a newly hired flight instructor. Data recovered from an on-board flight tracking system indicated that the airplane was maneuvering about 3,000 ft above ground level in the accident area; the final 35 seconds of data showed a near vertical descent toward the accident location. A witness saw the airplane descending vertically in a slight nose-down attitude "like a fluttering leaf." The airplane impacted the ground in a slightly nose-down and wings-level attitude, and ground impact marks around the airplane did not indicate any forward momentum. Examination of the airframe and engine found no abnormalities that would have precluded normal operation. The flight tracking data, the witness description, and the damage to the airplane are consistent with the airplane entering an aerodynamic stall and descending to ground impact. It could not be determined whether the stall was inadvertent or intentional (stall demonstration). Weight and balance calculations indicated that the airplane was about 40 pounds over maximum gross weight at takeoff and about 10 pounds over gross weight at the time of the accident; however, it is unlikely that this weight exceedance contributed to the loss of control.

The two-seat, high-wing, fixed-gear airplane, serial number 15284733, was manufactured in 1980. It was powered by a 125-horsepower Lycoming O-235-L2C engine and equipped with a Sensenich 70CKS6-0-52 fixed-pitch propeller. Review of copies of maintenance logbook records showed that an annual inspection was completed on July 17, 2015, at an hour meter reading of 99.4 hours, airframe total time of 9,678.2 hours, and engine time since major overhaul of 99.4 hours. Examination of the maintenance and flight department records revealed no unresolved maintenance discrepancies against the airplane before departure. Fueling records at KCDC established that the airplane was last fueled on October 5, 2015, with 14 gallons of 100-octane aviation fuel. The operator calculated, based on previous flight records, that the airplane departed with a total of 23 gallons of fuel on board. The current weight and balance documentation for the airplane was found in the airplane flight manual. The maximum gross weight for the airplane was 1,670 pounds. The gross weight at departure was estimated at 1,709 pounds. Based on estimated fuel burn and flight time, at the time of the accident, the airplane had a gross weight of 1,681 pounds. On October 5, 2015, at 1300 mountain daylight time, a Cessna 152, N6449M, impacted a dry lake bed about 6 nautical miles southwest of Cedar City Municipal Airport (KCDC), Cedar City, Utah. The two flight instructors were fatally injured, and the airplane was destroyed by impact forces. Upper Limit Aviation was operating the airplane under the provisions of 14 Code of Federal Regulations Part 91. The local company check flight departed KCDC about 1215. Visual meteorological conditions prevailed, and no flight plan had been filed. The operator reported that the purpose of the flight was for the chief pilot of the flight school to demonstrate the airplane to a newly hired flight instructor. Witnesses saw the airplane performing various maneuvers over the dry lake bed, which was used as a training area. One witness reported that, just before the accident, the airplane was descending in a near vertical fashion in a slight nose-low attitude and looked "like a fluttering leaf." The airplane was equipped with an on-board flight tracking system that uploaded recorded data points via satellite to the operator every 2 minutes. The unit retained the recorded data in non-volatile memory at 5 second intervals. The unit was downloaded, and a review of the last 14 minute segment of flight data showed the airplane departing from KCDC at 1246 using runway 26. The data showed the airplane making a right turn to the north at 1248:04. The airplane continued the right turn and made a touch-and-go landing on runway 20. At 1251:04, the airplane was climbing away from the runway. The flight track continued southwest toward the accident location. At 1256:04, the flight track passed over the accident site elevation (5,457 ft) at an altitude of 7,656 ft mean sea level(msl) and continued southwest in a gradual climb. The flight track showed a gradual left turn followed by a widening right climbing turn back toward the north. At 1259:49, the airplane's altitude was 8,661 ft msl, and the data then showed a descent to 8,179 ft msl during a 15 second period. By 1300:04, the airplane had climbed to an altitude of 8,353 ft msl. At 1300:19, the airplane was at an altitude of 8,559 ft msl (about 3,100 ft above ground level), and the remaining 35 seconds of data showed a near vertical descent toward the accident location. The last recorded data point at 1300:54 showed that the airplane was over the accident site, had a ground speed of 40 knots, and was at 5,580 ft msl. The Utah Department of Health, Office of the Medical Examiner, conducted postmortem examinations of both pilots. The cause of death for both pilots was reported as blunt force injuries. The Federal Aviation Administration's Bioaeronautical Sciences Research Laboratory, Oklahoma City, Oklahoma, performed toxicological testing of specimens of both pilots, which were negative for carbon monoxide, cyanide, volatiles, and tested drugs. After the wreckage was recovered, the engine was separated from the main wreckage and placed on a table to facilitate examination and disassembly. The propeller hub remained attached to the engine. Both propeller blades remained straight and exhibited no damage indicative of rotation at the time of impact. Engine compression and valve train continuity were established. The magnetos produced spark at all leads. The top spark plugs appeared new. The fuel strainer bowl was full of fuel, which tested negative for water, and the strainer screen was clean. The carburetor was impact displaced and was embedded in the left lower firewall. It was fractured radially at the throttle plate. The float bowl was removed and about 10 drops of fuel were observed and tested using Kolor Kut water disclosing paste with negative results. Hydraulic deformation was observed on one of the floats. All fuel lines were empty of any liquid. The fuel selector was removed, examined, and determined to be in the "ON" position. Investigators examined the wreckage at the accident scene. The damage to the airplane was consistent with impact in a right-wing-low, nose-down attitude. There were no ground impact marks around the airplane to indicate any forward momentum. Both fuel tanks exhibited hydraulic deformation in a downward direction and were breached. The outboard right wing leading edge exhibited tapering compression damage. The left wing was canted forward, and the right wing was canted aft. All primary flight control surfaces and major system components were identified and located at the wreckage site before the wreckage was recovered. The aileron and flap cables were cut by recovery personnel at the wing roots.