CEN13IA387 · Martin Charles A ZENITH STOL CH 750
Martin Charles A ZENITH STOL CH 750 · Incident: part(s) separation from aircraft en route
From Kirk Field (PGR) to Grosse Ile Municipal Airport (ONZ)
Event
- NTSB case
- CEN13IA387
- 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
- Incident
- 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
Martin Charles A ZENITH STOL CH 750
- Aircraft type
- Martin Charles ZENITH STOL CH 750
- 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
- N699TX
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Kirk Field (PGR), Paragould, ARTo Grosse Ile Municipal Airport (ONZ), Grosse Ile, MI
- Aircraft age
- About 1 year (built 2012)
- 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 · climb to 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
- Part(s) separation from aircraft
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Minor
Cause areas
- Aircraft › Aircraft propeller/rotor
- Personnel issues › Task performance
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The pilot reported that, during the climb after takeoff, the engine "developed an immediate and heavy vibration." The intensity of the vibration increased, and the pilot was considering shutting the engine down when the vibration abruptly ceased. Looking out the windshield, he observed that the propeller had separated from the airplane. The pilot subsequently executed a forced landing to a field. Metallurgical examination determined that the propeller separation was initiated by a fatigue failure of two propeller flange-to-engine crankshaft flange attachment bolts. Further examination revealed that an incorrect thread lock compound was used on the propeller bolts, and the presence of a second compound suggested that the bolts were not properly cleaned before installation. In addition, washers used in the installation did not correspond with the washers specified by the manufacturer. Finally, extensive fretting damage to the propeller and crankshaft flanges in conjunction with the limited number of flight hours indicated that the attachment bolts were not torqued sufficiently at the time of installation. Available maintenance records did not include any entry noting that the propeller assembly had been removed since the initial installation.
Probable cause
The improper installation of the propeller flange, which resulted in an in-flight separation of the propeller assembly.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CEN13IA387
- Event ID
- 20130702X64428
- Case number
- CEN13IA387
- 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: 892769683b52bf353c5ba7ead61bf1c26ebfcf27b55800706b61b00a72626bfc; retrieved 2026-09-15T22:04:40.129Z.