GAA18CA430 · Robinson R44 II
Skyline Helicopters Robinson R44 II · Accident: settling with power/vortex ring state during takeoff
From Okawville, IL to Okawville, IL
Event
- NTSB case
- GAA18CA430
- 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
Robinson R44 II
- Aircraft type
- Robinson R44
- 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
- N944DC
- Operator
- Skyline Helicopters
- Onboard fatalities
- Unknown
- Route
- From Okawville, ILTo Okawville, IL
- Aircraft age
- About 7 years (built 2011)
- 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 137: Agricultural
- 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
- Settling with power/vortex ring state
- 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 oper/perf/capability
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The helicopter pilot reported that, before starting agricultural application flights for the day, he calculated that about 490 lbs of chemical would bring the helicopter's weight near the manufacturer's maximum gross weight limitation. After an agricultural application flight, he landed the helicopter on a platform on top of a chemical reloading truck and reloaded the chemical tank with the precalculated amount. Once reloaded, he maintained a stabilized hover over the truck and transitioned to forward flight. When the helicopter cleared the truck, the "engine [made] a lower sound," and the main rotor low rpm horn activated, and the caution light illuminated. He immediately added power, lowered the collective to restore main rotor rpm, and pitched forward to gain airspeed, but the helicopter would not climb. He then decided to perform a roll-on landing on the adjacent field, but the helicopter landed hard.
The helicopter sustained substantial damage to the tail cone, tail rotor blades, and fuselage.
The pilot reported that there were no preaccident mechanical failures or malfunctions with the helicopter that would have precluded normal operation.
The pilot added that, after the accident, he recalculated the helicopter's weight and balance. He determined that, during the reloading operation, the chemical tank was not empty but had about 80 lbs of chemical remaining and that the added precalculated amount of chemical exceeded the helicopter's maximum gross weight limitation.
Probable cause
The pilot's improper preflight weight and balance calculation, which resulted in his operating the helicopter over its maximum gross takeoff weight and in its subsequent failure to climb.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record GAA18CA430
- Event ID
- 20180719X70018
- Case number
- GAA18CA430
- 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. Values present in the bulk record are kept.
- The date is the local date; the NTSB stores the UTC date 2018-07-09.
- API snapshot SHA-256: 245f60419bda23e75bf50f00f3971a0ff036ca8cacf45f4d5265614d2b9b9d5f; retrieved 2026-09-16T07:55:26.213Z.