CEN24LA137 · Enstrom Helicopter Corp 280C
Enstrom Helicopter Corp 280C · Accident: loss of engine power (partial) while maneuvering
Event
- NTSB case
- CEN24LA137
- 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
Enstrom Helicopter Corp 280C
- Aircraft type
- Enstrom 280
- 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
- N280WR
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From not recordedTo not recorded
- Aircraft age
- About 47 years (built 1977)
- 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
- Maneuvering · hover
- 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
- Loss of engine power (partial)
- 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 power plant
- Environmental issues › Task environment
- Personnel issues › Action/decision
- Personnel issues › Task performance
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
The pilot reported that he was repositioning the helicopter from his yard to a raised landing platform. When he initiated a hover to maneuver to the platform, the overboost warning light illuminated, the engine subsequently lost power, and the helicopter settled with only the right skid on the platform. The helicopter then rolled to the left, and the main rotor blades contacted the ground. The pilot reported that the overboost warning light had illuminated during a previous liftoff that day but that reducing manifold pressure had effectively extinguished the light. According to maintenance records, the idle mixture adjustment had been adjusted during the last annual inspection about 7 flight hours before the accident. Although the Rotorcraft Flight Manual stated that the mixture control must be in the full-rich position for takeoff and landing operations (to ensure adequate engine cooling), the pilot reported that, following this maintenance, he had to manually lean the cockpit mixture control during idle and low-power operations to prevent the engine from running excessively rich. Postaccident examination of the engine found that the idle mixture adjustment was set excessively rich. No other preaccident mechanical failures or malfunctions were found with the helicopter that would have precluded normal operation. According to Enstrom Service Information Letter (SIL) No. 0069, excessively rich idle mixture settings can result in engine roughness and engine stoppage following reductions to low-power conditions. These characteristics are consistent with the pilot’s reported need to manually lean the mixture during idle operation after the most recent maintenance. Because the pilot reported routinely leaning the cockpit mixture control during low-power operations after the maintenance was performed, it is likely that the mixture control was not returned to the full-rich position before repositioning to the landing platform landing pad, which resulted in an overly lean condition and power loss. It is likely that the over boost light illuminated due to the lean mixture which resulted in abnormally high exhaust gas temperature and led to turbocharger overspeed.
Probable cause
The pilot’s improper manual engine mixture management which resulted in a loss of power. Contributing to the accident was the mechanic’s improper setting of the idle mixture adjustment and the pilot’s decision to take off with a known mechanical deficiency.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CEN24LA137
- Event ID
- 20240318193955
- Case number
- CEN24LA137
- 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, cause areas. 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: 5896b1ab0602cd01996d14ae6f188b14cc6c077627a16b7ecc9cbfc1b5ae65e5; retrieved 2026-09-16T18:36:16.156Z.