Takeoff & Initial Climb · NTSB WPR21FA272
MOONEY M20J — Dinsmore, CA
| Date | July 15, 2021 |
| Location | Dinsmore, CA |
| Aircraft | MOONEY M20J |
| Purpose of flight | Personal |
| Conditions | Day · Visual Meteorological Cond |
| Phase / occurrence | Takeoff Collision during takeoff/land |
| Pilot age | 69 |
| Pilot total time | 2,400 hrs · Experienced |
| Time in type | Unknown |
| Fatalities | 4 |
Probable cause
NTSB findings
- Aircraft-Aircraft power plant-Engine (reciprocating)-Recip engine power section-Fatigue/wear/corrosion
- Aircraft-Aircraft oper/perf/capability-Performance/control parameters-Climb rate-Attain/maintain not possible
- Environmental issues-Physical environment-Object/animal/substance-Tree(s)-Contributed to outcome
What happened
A witness who was near the departure airport reported observing the airplane circle the area, land on the runway, and stop at the midpoint of the runway. At that time, three people disembarked from the airplane, one of whom walked around the airplane. All three people then boarded the airplane, and the airplane taxied toward the approach end of the runway. The witness observed the airplane take off and stated that the airplane appeared to have rotated just short of the displaced runway threshold. The witness stated that the airplane “barely cleared the fence” and that the rotation was not smooth. Subsequently, the airplane impacted trees just beyond the departure end of the runway, where a postimpact fire ensued.
Postaccident examination of the engine revealed that the intake camlobes were worn and exhibited a rounded (instead of an elliptical) shape. The corresponding tappets for the intake cam lobes were galled. The alteration of the camlobe profile will in turn alter the amount and duration of the intake valves opening, thus negatively affecting power output. As a result, takeoff and climb performance would be directly affected. Although the extent of the degradation to the accident engine's power output could not be determined from the available evidence, the degradation was likely sufficient to cause a partial loss of engine power.