ERA14LA293 · Schweizer 269C-1
Schweizer 269C-1 · Accident: ground resonance while standing
From Lehigh Valley International Airport (ABE) to Lehigh Valley International Airport (ABE)
Event
- NTSB case
- ERA14LA293
- 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
- N152CC
- Operator
- Ace Pilot Training
- Onboard fatalities
- Unknown
- Route
- From Lehigh Valley International Airport (ABE), Allentown, PATo Lehigh Valley International Airport (ABE), Allentown, PA
- Aircraft age
- About 12 years (built 2002)
- 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
- Standing · engine(s) operating
- 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
- Personnel issues › Task performance
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The student pilot landed the helicopter after a 40-minute flight and started the engine shut down procedures. She stated that she applied the collective friction and started the timer, running the engine at 2,500 rpm for a cool-down period. She turned off the fuel boost pump and radios and referred to the checklist to ensure she had completed the proper items. She then engaged the collective friction and was tightening the cyclic friction at the cyclic base when the helicopter developed ground resonance. The student pilot could not get the helicopter airborne with the collective friction engaged, so she rolled the throttle to idle. The resonance continued to increase and, "in a matter of seconds, the helicopter shook itself apart."
The helicopter had four poppet-type, nitrogen-charged hydraulic units (dampers) in the landing gear assembly to reduce landing shock and help prevent ground resonance. The four dampers were removed from the helicopter and pressure tested; all four failed to meet manufacturer's specifications. Without the airframe protection provided by the dampers, oscillations occurred that resulted in the helicopter rocking on its landing gear and the tailboom twisting toward the right side of the helicopter where it joined the main structure.
Maintenance instructions noted that the landing gear dampers would experience a decrease in pressure with helicopter usage and required that they be extension-checked during each 100-hour inspection or every 6 months, whichever occurred first. The helicopter's most recent 100-hour inspection occurred about 2 months before the accident, and it had been operated 58 hours since the inspection. Review of maintenance records for the most recent 100-hour inspection and about 800 flight hours before the accident revealed no mention of any maintenance actions involving the dampers.
Probable cause
Inadequate inspection and maintenance of the helicopter’s landing gear dampers, which resulted in ground resonance during helicopter shutdown.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record ERA14LA293
- Event ID
- 20140617X30814
- Case number
- ERA14LA293
- 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: 27e0a21f12dd0a363658a5fe8aaad3a767ec674c91358363017632ea524d0769; retrieved 2026-09-16T00:05:45.248Z.