CEN12LA353 · Schweizer 269C-1
My Sky Schweizer 269C-1 · Accident: ground resonance during takeoff
From Spirit of St Louis Airport (SUS) to Spirit of St Louis Airport (SUS)
Event
- NTSB case
- CEN12LA353
- 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
Schweizer 269C-1
- Aircraft type
- Schweizer 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
- N345MH
- Operator
- My Sky
- Onboard fatalities
- Unknown
- Route
- From Spirit of St Louis Airport (SUS), Chesterfield, MOTo Spirit of St Louis Airport (SUS), Chesterfield, MO
- 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 systems
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The pilot reported that the helicopter started to shake as he increased power for takeoff on the solo instructional flight. He reduced engine power, but the oscillations became stronger and ultimately uncontrollable, resulting in substantial damage to the main and tail rotor blades, partial separation of the main rotor mast from the aft fuselage structure, and partial separation of the tail boom from the fuselage. The pilot shut down the engine and exited the helicopter. The pilot was receiving training for the addition of a helicopter rating and was operating the helicopter under the authority of a logbook solo endorsement. Postaccident testing revealed that all four landing gear dampers failed to meet the manufacturer’s specifications. The forward dampers were undercharged, while the aft dampers were overcharged. Maintenance records indicated that the aft dampers had been replaced with overhauled units about 1 month before the accident. The forward dampers had not been replaced. Maintenance procedures required periodic inspection of the landing gear dampers, and the operator stated that the inspection procedure was accomplished after installation of the overhauled dampers. A review of the overhaul procedure for the landing gear dampers revealed that the procedure did not provide for functional testing of the dampers following overhaul, which would have identified the out-of-specification condition before installation.
Probable cause
The undercharged and overcharged landing gear dampers, which allowed initiation of the ground resonance event from which the pilot was unable to recover due to his limited experience in helicopters. Contributing to the accident was the ineffective damper inspection conducted by the operator’s maintenance personnel and the improper overhaul procedure by the overhaul facility that resulted in overcharged dampers being provided to the operator. Also contributing was the lack of any final acceptance testing criteria for the dampers in the manufacturer’s overhaul procedure manual.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CEN12LA353
- Event ID
- 20120611X14804
- Case number
- CEN12LA353
- 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: 3e4106f70f569166a6c48f24d1208a68905235a84b055bb8de21ce0928500b78; retrieved 2026-09-15T18:27:14.637Z.