WPR21FA272 · Mooney M20J
Mooney M20J · Accident: loss of engine power (partial) during takeoff
Event
- NTSB case
- WPR21FA272
- Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
- Accident
- InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
- Completed
- API-reported fatalities
- 4 · all aircraft and ground
- Ground fatalities
- Unknown
- OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
- General aviation
- WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
- Visual Meteorological Cond
Mooney M20J
- Aircraft type
- Mooney M20
- Category
- Airplane
- RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
- N4474H
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From not recordedTo not recorded
- Aircraft age
- Not recorded
- Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
- Part 91: General Aviation
- Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
- Takeoff
- Defining eventThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
- Loss of engine power (partial)
- Also codedOther events the NTSB coded in the sequence, such as a wire strike after a loss of power. Flight Findings uses them for its kinds of event. Glossary
- Tree(s)
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Destroyed
Cause areas
- Aircraft › Aircraft oper/perf/capability
- Aircraft › Aircraft power plant
- Environmental issues › Physical environment
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
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.
Probable cause
The airplane’s degraded engine performance due to wear to the intake cam lobes, which diminished the airplane’s takeoff and climb performance, resulting in a subsequent collision with trees.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record WPR21FA272
- Event ID
- 20210715103489
- Case number
- WPR21FA272
- Dataset
- full-current
- Source SHA-256
- 5cf380f0061817c0331a6b2d8cc7e0ee3a79bea469a1001dc5c10e56f35f5ab3
Source notes (4)
- Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
- Filled from the NTSB case API where the bulk record had no value: investigation status, cause areas. Values present in the bulk record are kept.
- The date is the local date, which is the same as the UTC date the NTSB stores.
- API snapshot SHA-256: 8b643475bd0194373231bce341d5dc5bc7cfc9b5d3bcebf7e9e61f25e2e0833b; retrieved 2026-09-15T07:31:43.064Z.