WPR24LA260 · Kitfox Series V
Kitfox Series V · Accident: powerplant system/component malfunction/failure during initial climb
From La Grande/Union County Airport (LGD) to an unrecorded destination
Event
- NTSB case
- WPR24LA260
- 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
Kitfox Series V
- Aircraft type
- Kitfox SERIES
- 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
- N53562
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From La Grande/Union County Airport (LGD), La Grande, ORTo not recorded
- Aircraft age
- About 24 years (built 2000)
- 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
- Initial climb
- 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
- Powerplant system/component malfunction/failure
- 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 handling/service
- 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 shortly after takeoff he heard a loud, violent bang that shook the airplane. He could see that the propeller was not moving and subsequently made a forced landing to a nearby beet field. After the airplane came to rest, the pilot observed that two of the three propeller blades had separated from the propeller hub. He later found one of the missing propeller blades about 3,000 ft from the main wreckage; the remaining propeller blade was not located. Examination of the propeller hub, the two recovered blades, and the blade roots revealed that all three blades had fractured at the retention grooves near the blade roots. Examination of the fracture surfaces revealed thumbnail cracks extending from the blades’ surfaces inward, consistent with fatigue failure. The examination evaluated whether the blades were installed in accordance with the propeller manufacturer’s instructions. The instructions called for the hub bolts to be torqued to between 75 and 100 in-lbs. The airplane’s logbook did not have records of the tightening torque used on the hub assembly. Although the hub bolt torque value was measured at 32 in-lbs., the measured torque was likely affected by the absence of two of the three propeller blade root cores. The gap between the two halves of the hub was measured between 0.016 and 0.022 inches, which is less than the manufacturer’s design specification of 0.030 inches, and consistent with excessive clamping force applied by overtightening of the hub bolts. All three blade retention bores in the hub showed a black residue, especially at the outboard end of each bore near the hub split line. This appeared to be material transfer from the blades’ polymer caps to the hub. The measured widths of the impressions on the caps left by the hub split line were also less than 0.030 inches, again consistent with overtightening of the hub bolts. The overtightened bolts would have applied excess compressive stress to the blade roots, resulting in damage that progressed to fatigue failure. Review of available maintenance records showed no evidence of propeller overhaul consistent with the manufacturer’s recommended time between overhauls for their propellers.
Probable cause
Separation of the propeller blades from progressive damage at the blade roots due to overtightening of the hub bolts.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record WPR24LA260
- Event ID
- 20240729194797
- Case number
- WPR24LA260
- 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: 0635d45599750b3d5109b3a069c9a6ba2e65c8127ef93f9ba79431281a4f5dfe; retrieved 2026-09-16T19:06:08.290Z.