WPR17LA009 · Gray Jim Robert Exec 90
Gray Jim Robert Exec 90 · Accident: loss of engine power (partial) during takeoff
From Caldwell Executive Airport (EUL) to Caldwell Executive Airport (EUL)
Event
- NTSB case
- WPR17LA009
- 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
Gray Jim Robert Exec 90
- Aircraft type
- Gray Jim Robert EXEC 90
- 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
- N716JB
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Caldwell Executive Airport (EUL), Caldwell, IDTo Caldwell Executive Airport (EUL), Caldwell, ID
- Aircraft age
- About 18 years (built 1998)
- 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
- 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
- Personnel issues › Task performance
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
Shortly after takeoff for the personal flight, about 15 to 20 ft above ground level, the experimental amateur-built helicopter suddenly yawed right, followed by a partial loss of engine power. The private pilot then performed a partial nose-up, collective-down maneuver, but due to the low altitude and not being able to maintain sufficient rotor rpm, he chose to land in soft dirt off the side of the runway; the helicopter landed hard.
The pilot had recently changed the alternator belt. A postaccident examination of the helicopter revealed that, during the maintenance, the pilot failed to properly tighten the tension bolts, which resulted in inadequate voltage to sustain ignition and the subsequent partial loss of engine power.
Probable cause
The pilot's failure to properly tighten the tension bolts during the installation of the alternator belt, which resulted in inadequate voltage to sustain ignition and the subsequent partial loss of engine power.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record WPR17LA009
- Event ID
- 20161019X35516
- Case number
- WPR17LA009
- 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: 411c8795dfcb6945af034f49a8b8842f21ddbf6df2307340fd8f6af33611cfb0; retrieved 2026-09-16T04:26:20.841Z.