WPR19TA245 · Bell 47G 4A
Bell 47G 4A · Accident: loss of control in flight while maneuvering
Event
- NTSB case
- WPR19TA245
- 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
Bell 47G 4A
- Aircraft type
- Bell 47
- 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
- N6064H
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From not recordedTo not recorded
- Aircraft age
- About 43 years (built 1976)
- 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 control in flight
- 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
- Personnel issues › Experience/knowledge
- 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
During the flight before the accident, the pilot of the helicopter observed that the engine would not produce adequate power to keep the rotor rpm within the green arc of the tachometer, and witnesses reported hearing backfiring from the engine. The pilot sought the assistance of an acquaintance to help him perform maintenance on the helicopter. The acquaintance told the pilot that he was a commercial pilot with 3,000 hours of flight experience in helicopters, and 300 hours in the accident helicopter make and model. After performing maintenance on the helicopter, they relocated the helicopter to a helipad and boarded the helicopter for flight. The pilot lifted the helicopter to a hover but soon began to have difficulty maintaining control and transferred the flight controls to the passenger. The passenger acknowledged that he had the flight controls. Shortly thereafter, the passenger lost control of the helicopter and it drifted backward into a fuel cart and rolled onto its left side. A postaccident interview and review of Federal Aviation Administration records revealed that the passenger did not possess a pilot certificate. Examination of the airframe revealed no preaccident mechanical malfunctions or failures that would have precluded normal operation. Examination of the engine revealed that the No. 1 cylinder inner and outer intake valve springs were fractured and collapsed, which was likely the cause of the low engine and rotor speed on the previous flight.
Probable cause
The noncertificated passenger’s loss of control during attempted hover operations.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record WPR19TA245
- Event ID
- 20190828X74159
- Case number
- WPR19TA245
- 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: local date, investigation status, coordinates, cause areas. Values present in the bulk record are kept.
- The date is the local date; the NTSB stores the UTC date 2019-08-28.
- API snapshot SHA-256: a6b045601c0fc7eb97ae68240d0f55a8ddbf061e9a54cc331b3f806d5cfec536; retrieved 2026-09-16T09:54:02.134Z.