Controlled Flight Into Terrain · NTSB WPR20FA057
Thunder Mustang TM-1 — Santa Clarita, CA
| Date | January 4, 2020 |
| Location | Santa Clarita, CA |
| Aircraft | Thunder Mustang TM-1 (amateur-built) |
| Purpose of flight | Personal |
| Conditions | Day · Visual Meteorological Cond |
| Phase / occurrence | Emergency descent Controlled flight into terr/obj (CFIT) |
| Pilot age | 73 |
| Pilot total time | 4,500 hrs · High time |
| Time in type | Unknown |
| Fatalities | 1 |
Probable cause
NTSB findings
- Aircraft-Aircraft power plant-Engine (reciprocating)-Recip eng cyl section-Malfunction
- Environmental issues-Task environment-Physical workspace-Visibility-Contributed to outcome
- Personnel issues-Psychological-Attention/monitoring-Monitoring environment-Pilot
- Environmental issues-Physical environment-Object/animal/substance-Tree(s)-Contributed to outcome
What happened
The pilot departed for flight in an amateur-built experimental airplane. A few minutes after takeoff, the pilot made a distress call to the airport tower controller stating a loss of engine power and a cockpit visibility issue. A witness observed the airplane maneuvering at a low altitude with smoke trailing from the airplane. Subsequently, the airplane struck a tree and impacted terrain in a grassy field located in the median of an interstate’s off-ramp, destroying the airplane.
Postaccident examination of the engine revealed damage that was consistent with detonation. One cylinder had material deformation that had burnt through the crankcase. Other cylinders had varying degrees of material deformation on their piston faces and cylinder heads, and the piston faces, and cylinder heads were absent of any carbon buildup. During the forced landing, the hole in the crankcase would have leaked coolant and oil, creating smoke and limiting the visibility from the cockpit, which likely would have prevented the pilot from seeing and avoiding the tree. The specific reason for the detonation could not be determined.