CEN12LA247 · Hughes 269A UNDESIGNAT
Hughes 269A UNDESIGNAT · Accident: ground resonance during takeoff
From Grinnell Regional Airport (GGI) to Grinnell Regional Airport (GGI)
Narrative check · The NTSB narrative appears to contradict this record's aircraft involved. Values are shown as recorded, not corrected; compare with the narrative.
Event
- NTSB case
- CEN12LA247
- 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
Hughes 269A UNDESIGNAT Narrative disagrees
- Aircraft type
- Hughes 269
- Category
- Helicopter
- 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
- N69HJ
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Grinnell Regional Airport (GGI), Grinnell, IATo Grinnell Regional Airport (GGI), Grinnell, IA
- 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
- 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
- Ground resonance
- 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 oper/perf/capability
- Personnel issues › Action/decision
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The helicopter began to vibrate as the pilot raised the collective for liftoff. The pilot lowered the collective and closed the throttle when the vibration began; however, he was too late in recognizing the onset of ground resonance, which resulted in a violent, uncontrollable oscillation and separation of the tail boom from the fuselage. Examination of the helicopter revealed no anomalies that would have precluded normal operation.
Probable cause
The pilot's improper liftoff technique, which resulted in ground resonance, and the pilot's delayed recognition of the ground resonance.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CEN12LA247
- Event ID
- 20120417X72641
- Case number
- CEN12LA247
- 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: 7229b4159b4163f0db37b95bbbd8bc49915a6e47edac7370b19604a94adecdf5; retrieved 2026-09-15T17:48:34.216Z.