NTSB Factual Report

On July 19, 2016, about 1900 central daylight time, a Meyers 200B airplane, N229RS, conducted a forced landing to a field near Huron, South Dakota. The airline transport rated pilot was not injured and passenger received minor injuries. The airplane was substantially damaged during the landing. The airplane was registered to and operated by a private individual, under the provisions of 14 Code of Federal Regulations Part 91 as a cross country flight. Visual meteorological conditions prevailed at the time.

The pilot reported the cross-county flight had an en route stop at the Wendover Airport (KENV), Wendover, Utah, on July 17, 2016. During flight, he noted oil on the windscreen, so he stopped in Casper, Wyoming, for maintenance personnel to look at the airplane. The pilot reported that maintenance personnel identified several discrepancies; the crankshaft seal was leaking, the propeller bolts did not have enough threads showing through the crankshaft flange, the throttle linkage connecting the landing gear warning horn was loose, and the fuel distributor drain fitting did not have an overboard line.

In addition, maintenance personnel also noted that a bolt holding the throttle cable bracket was loose. The bolt was worn and not safetied to the mixture control bolt. Since the maintenance facility did not have an exact replacement bolt, the mechanic selected a bolt, absent holes in the bolt head intended for safety wire. He then drilled a hole in the bolt head for the safety wire, and installed the bolt. The mechanic added that he installed the safety wire through the throttle bolt head, then down to the mixture control bolt.

During the maintenance work, the airplane pilot/owner periodically inspected or observed work as noted by maintenance personnel and security camera footage provided by the maintenance facility. After the accident, the pilot provided the Federal Aviation Administration (FAA) inspector a photo of the throttle linkage area, and the photo confirmed that the safety wire was in place during that maintenance.

On July 19, 2016, after maintenance personnel completed work on the airplane, the pilot started the engine and completed an engine run-up. The pilot then took the airplane on a test flight around the traffic pattern, and after landing, the airplane was checked for leaks.

The pilot and passenger then continued their flight, stopping for fuel about 1830 at the Huron Regional Airport, (KHON), Huron, South Dakota. After departing and reaching an altitude of 2,300 ft, the pilot reduced the throttle, and the engine lost power. The engine then continued to run at idle power. The pilot manipulated the throttle; however, the engine only responded with momentary increases in rpms. Subsequently, the pilot conducted a forced landing in a field, and the airplane came to rest upright. Substantial damage was noted to the airplane's fuselage.

Following the forced landing, the pilot added that after a period of time, he re-entered the airplane to ensure the electrical power and fuel and were off and there was no fire. In addition, he removed the engine cowling and found the throttle linkage was "disconnected or broken."

A post-crash examination of the airplane by an FAA inspector, noted that the bolt holding the throttle cable was missing. This was the bolt that the maintenance personnel reportedly installed with the safety wire earlier that day. The absence of the bolt allowed the throttle cable to "float", meaning, manipulating the throttle control from the cabin, would not govern the engine's throttle position. The throttle bolt was not located. The mixture control bolt was in place; however, the safety wire which ran from the mixture control bolt to the throttle bracket bolt was also missing and not recovered.

The airplane was recovered to the salvage yard located at Beegles Aircraft Service, Greeley, Colorado. During an inspection there, Beegles personnel reported that after removing the top cowling, they found a bolt, laying in a bottom area of the cowling. The bolt; however, had manufactured holes in the head, not new in appearance, and was not the missing bolt.

A review of FAA records revealed that the airplane's original Continental IO-470 engine was replaced with a Continental IO-550 engine under a field approval. The last annual inspection was completed on May 2, 2016, and the airplane had accumulated 10.44 hours, since the annual inspection.

NTSB Probable Cause

The partial loss of engine power due an unsecured throttle cable. Contributing to the unsecured throttle cable was the missing bolt and associated safety wire; the reason for the missing bolt and safety wire could not be determined.