WPR21LA020 · Piper PA-28-180
Piper PA-28-180 · Accident: loss of engine power (partial) en route
From Marana Regional Airport (KAVQ) to an unrecorded destination
Event
- NTSB case
- WPR21LA020
- 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
- Event fatalities
- Unknown
- 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
Piper PA-28-180
- Aircraft type
- Piper PA-28
- 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
- N7405W
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Marana Regional Airport (KAVQ), Marana, AZTo 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
- En route · cruise
- 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)
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Substantial
Cause areas
- Aircraft › Aircraft power plant
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
The pilot reported that, while in cruise flight about 8,000 ft mean sea level, there was a loud bang followed by severe engine vibration and the engine lost partial power. The pilot attempted to troubleshoot; however, the engine continued to produce less than full power. The pilot declared an emergency and performed a forced landing to a highway, during which the airplane’s right wing impacted a barbed wire fence, resulting in substantial damage. Examination of the engine revealed a stuck exhaust valve on the No. 4 cylinder. The exhaust valve head had separated from the valve stem. The loose valve head was found in the cylinder’s combustion chamber; the combustion chamber and piston dome exhibited damage consistent with repeated contact with the valve head. The loss of engine power is consistent with the failure of the No. 4 cylinder exhaust valve; however, the reason for the valve failure could not be determined based on the available information.
Probable cause
A partial loss of engine power due to the failure of the No. 4 cylinder exhaust valve.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record WPR21LA020
- Event ID
- 20201022102177
- Case number
- WPR21LA020
- 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, coordinates, 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: 33a86400f4845362dae3c7e38f856c4daff41ee5dea761dfea5bde9275c5c28b; retrieved 2026-09-16T13:16:21.536Z.