CHI95TA243 · Schweizer 300C
Schweizer 300C · Accident: loss of control on ground/water during landing
Event
- NTSB case
- CHI95TA243
- 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
- 0
- 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 300C
- Aircraft type
- Schweizer 300
- 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
- N643KC
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From not recordedTo not recorded
- 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
- Landing
- First occurrenceThe 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
- Loss of control on ground/water
- 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
- Company maintenance personnel › Maintenance, service of aircraft/equipment, improper
- Ground resonance › Encountered
- Landing gear, main gear shock absorbing strut › Pressure too low
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The pilot reported that he made a normal, smooth landing. He said the helicopter had been on the ground about 5 to 6 seconds and that he had reduced the engine rpm back between 2700 and 2800 RPM's, when he noticed a vibration in the helicopter. The pilot said he rolled in the throttle to 3100 rpm and attempted to get the helicopter into a hover. He reported that the vibrations were severe, and about one second later, the left skid collapsed and the main rotor contacted the tailboom. He secured and evacuated the helicopter after all motion had stopped. Tests revealed that the charge pressure for all four landing gear dampers was lower than that specified by the maintenance instructions. The maintenance instructions warned that improper shock strut pressure levels may result in ground resonance and destruction of the helicopter. Examination of the main rotor head dampers revealed no evidence of preexisting cracks or fatigue.
Probable cause
ground resonance as a result of improper servicing of the main landing gear dampers.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CHI95TA243
- Event ID
- 20001207X03924
- Case number
- CHI95TA243
- Dataset
- historical-pre2008
- Source SHA-256
- 89e2df6d848e7ab3b42e7d7c7a03ff403303057a26ca04c95b3ea67201c3ce74
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: local date, investigation status. Values present in the bulk record are kept.
- The date is the local date; the NTSB stores the UTC date 1995-07-28.
- API snapshot SHA-256: a2f9c7f9fee8cbad1be77616a4f424b4ecf5c6a9223bc93f85ead3f0c5b0664c; retrieved 2026-09-21T22:08:01.583Z.