WPR21LA341 · Robinson R44 II
Yavapai County Robinson R44 II · Accident: collision during takeoff/landing
From Prescott Regional Airport - Ernest A. Love Field (KPRC) to Prescott Regional Airport - Ernest A. Love Field (KPRC)
Event
- NTSB case
- WPR21LA341
- 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
- Event fatalities
- Unknown
- 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
- N544SH
- Operator
- Yavapai County
- Onboard fatalities
- Unknown
- Route
- From Prescott Regional Airport - Ernest A. Love Field (KPRC), Prescott, AZTo Prescott Regional Airport - Ernest A. Love Field (KPRC), Prescott, AZ
- Aircraft age
- About 16 years (built 2005)
- 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
- Landing · flare/touchdown
- 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
- Collision during takeoff/landing
- Also codedOther events the NTSB coded in the sequence, such as a wire strike after a loss of power. Flight Findings uses them for its kinds of event. Glossary
- Tree(s)
- 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
- Environmental issues › Conditions/weather/phenomena
- Environmental issues › Physical environment
- Personnel issues › Action/decision
- Personnel issues › Task performance
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The pilot reported that, while taking off from a remote mountainous site, the helicopter encountered some turbulent air and the main rotor RPM decayed. He elected to abort the takeoff and land at a site about 20-30 ft from the original location. During the landing, the main rotor blades struck a tree. The helicopter sustained substantial damage to main rotor blades and main rotor hub assembly. The pilot reported that there were no preaccident mechanical malfunctions or failures with the helicopter that would have precluded normal operation. He also reported that the accident could have been avoided by taking more time to calculate and determine the density altitude and out of ground effect performance of the helicopter at the time of the accident.
Probable cause
The pilot's inadequate preflight performance calculations which resulted in an aborted takeoff and collision with trees.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record WPR21LA341
- Event ID
- 20210913103849
- Case number
- WPR21LA341
- 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, cause areas. Values present in the bulk record are kept.
- The date is the local date; the NTSB stores the UTC date 2021-08-28.
- API snapshot SHA-256: 41b3eae6ab4d980f00578a4861af385ca471240d021aa0943c08169285afbd9e; retrieved 2026-09-16T14:31:19.028Z.