CEN18LA044 · Cessna 170B
Cessna 170B · Accident: flight control system malfunction/failure during landing
From Poplar Grove Airport (C77) to Dacy Airport (0C0)
Event
- NTSB case
- CEN18LA044
- 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
Cessna 170B
- Aircraft type
- Cessna 170
- 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
- N2766D
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Poplar Grove Airport (C77), Poplar Grove, ILTo Dacy Airport (0C0), Harvard, IL
- Aircraft age
- About 65 years (built 1952)
- 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
- Landing · flare/touchdown
- 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
- Flight control system 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 systems
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
The private pilot was conducting a personal flight. He reported that he experienced a "complete loss of flight controls" during the landing flare. The main landing gear settled to the runway; during the landing roll, the pilot was able to reach the copilot-side control yoke and completed the landing, but the airplane received substantial damage.
A postaccident examination of the airplane revealed that the rivet in the universal joint for the pilot-side control yoke had failed, causing the universal joint to disassemble. The examination of the universal joint also revealed that the assembly seized and would not articulate as designed. The assembly seized due to galling wear between the center pin and the yoke ear holes and between the swivel blocks and the yoke ears, resulting in high alternating stresses in the rivet that held the half pins in place. The high alternative stresses in the rivet caused the rivet to fail by low-cycle reversed-bending fatigue fracture. The universal joint design was prone to galling wear and seizure.
Maintenance records indicated the universal joint had been replaced 1.5 years before the accident and had acquired 199.1 hours of flight time since being installed. The component had been maintained in accordance with the requirements prescribed in the airframe manufacturer's service manual. No evidence suggested that the failure was related to improper maintenance or lubrication.
Probable cause
The failure of the universal joint in the pilot-side flight control yoke due to the fatigue fracture of a rivet within the universal joint. Contributing to the universal joint failure was the universal joint design, which was prone to galling wear and seizure.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CEN18LA044
- Event ID
- 20171204X53544
- Case number
- CEN18LA044
- 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. 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: e28d822994f94756bead79d3f4dd0d39a9a9bef5f6d6430f6d7f90f24565b38d; retrieved 2026-09-16T06:04:25.044Z.