Mechanical & Engine Failure · NTSB WPR16FA102
BEECH G35 — Surprise, AZ
| Date | May 7, 2016 |
| Location | Surprise, AZ |
| Aircraft | BEECH G35 |
| Purpose of flight | Instructional |
| Conditions | Day · Visual Meteorological Cond |
| Phase / occurrence | Enroute Loss of engine power (partial) |
| Pilot age | 32 |
| Pilot total time | 100 hrs · Low time |
| Time in type | Unknown |
| Fatalities | 1, 1 serious |
Probable cause
NTSB findings
- Aircraft-Fluids/misc hardware-Misc hardware-(general)-Not installed/available - C
- Personnel issues-Task performance-Maintenance-Installation-Maintenance personnel - C
What happened
The flight instructor was asked to complete a maintenance test flight of the airplane following the installation of a repaired carburetor. He elected to use the flight to provide instruction to the private pilot who had requested a checkout in the airplane. The private pilot reported that the flight was initially normal, but then the engine stopped responding to throttle control. According to the private pilot, the engine remained at idle power as the airplane descended and impacted trees in a residential area.
Examination of the wreckage revealed that the carburetor throttle cable was detached from the throttle body linkage. The bolt and castellated nut used to secure the throttle cable to the linkage were found lying separately in the engine cowling; there was no evidence that a cotter pin had been used to secure the nut on the bolt, as required.
It is likely that the loss of engine power resulted from the failure of the mechanic who installed the carburetor to install the cotter pin when he attached the throttle cable to the carburetor. During the maintenance test flight, the castellated nut backed off of the bolt, which resulted in a loss of throttle control.