CEN14LA334 · Piper PA-28-140
Iron Compass Aviation Piper PA-28-140 · Accident: loss of engine power (partial) during takeoff
From Granbury Regional Airport (GDJ) to Waco Regional Airport (ACT)
Event
- NTSB case
- CEN14LA334
- 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
- 0 · 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
Piper PA-28-140
- 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
- N9898W
- Operator
- Iron Compass Aviation
- Onboard fatalities
- Unknown
- Route
- From Granbury Regional Airport (GDJ), Granbury, TXTo Waco Regional Airport (ACT), Waco, TX
- Aircraft age
- About 47 years (built 1967)
- 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)
- 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 as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The flight instructor reported that, after takeoff, when the airplane was about 500 ft above ground level, the engine started to run roughly and lose power. The engine rpm decreased to about 1,100 rpm as the flight instructor attempted to turn the airplane 180 degrees back toward the airport. However, he was unable to land at the airport, so he made a forced landing to a field short of the runway.
During a postaccident engine test run, the engine initially ran roughly, and black smoke was observed coming from the exhaust. After a brief warmup, the engine could only produce about 1,600 rpm at full throttle, and the engine test run was stopped. The examination of the No. 3 cylinder revealed that the exhaust valve was broken in several pieces and that some fragments remained in the cylinder, which produced gouging and scraping to the piston and cylinder head. The broken exhaust valve, spring, exhaust valve keepers, and rotating cap exhibited carbon buildup. Examination revealed a wear pattern on the top of the No. 3 cylinder exhaust valve rotator cap consistent with rocker arm wear. No rotational signatures were observed along the edge of the cap near the heavy carbon buildup, indicating that the rotator cap had stopped rotating, which subsequently led to a hot spot on the exhaust valve and caused the valve to fail.
Probable cause
The partial loss of engine power due to the failure of the exhaust valve.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CEN14LA334
- Event ID
- 20140702X34701
- Case number
- CEN14LA334
- 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. 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: 73694fdc43071cfa4bb219baf88e546e7f68b6ae2f768e2fbb9d8f6d7dd7dfac; retrieved 2026-09-16T00:47:33.253Z.