Air Methods Eurocopter EC130 B4 accident
Eurocopter EC130 B4 · Accident: loss of tail rotor effectiveness during landing
From St Francis Hospital Heliport (4OK3) to an unrecorded destination
Event
- NTSB case
- CEN21LA153
- 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
- Charter & commuter
- 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
Eurocopter EC130 B4
- Aircraft type
- Eurocopter EC130
- 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
- N259AM
- Operator
- Air Methods
- Onboard fatalities
- Unknown
- Route
- From St Francis Hospital Heliport (4OK3), Tulsa, OKTo not recorded
- Aircraft age
- About 10 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 135: Air Taxi & Commuter
- 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
- 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 tail rotor effectiveness
- 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
- Environmental issues › Conditions/weather/phenomena
- Personnel issues › Action/decision
- Personnel issues › Task performance
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
After a west-southwest approach to the airport the pilot entered a low altitude hover near a taxiway intersection where he intended to turn left and join a north/south taxiway before continuing in a hover taxi south toward the ramp. During the counterclockwise turn to join the taxiway, the helicopter’s yaw rate increased as the tail passed through the north-northeast wind. The pilot allowed the helicopter to continue in the turn, despite an increasing left yaw rate, until the nose of the helicopter had realigned with the wind. However, at that point, he was unable to stop the counterclockwise rotation and the helicopter completed at least 2 revolutions before a landing skid struck the ground and the helicopter spun off the taxiway into a grass easement. The pilot and two medical personnel were not injured. The horizontal stabilizer attach fitting on the tail boom was fractured and required replacement. The operator did not report any mechanical malfunctions with the helicopter that would have precluded normal operation.
According to a weather report issued about 6 minutes before the accident, the surface wind at the airport was from north-northeast at 8 knots. During the subsequent hour, the wind direction remained unchanged, but the wind speed had increased to 11 knots with 17 knot gusts. A loss of tail rotor effectiveness likely occurred when the helicopter encountered a wind gust during the left turn, which resulted in an increasing counterclockwise yaw rate that the pilot was unable to control.
Probable cause
The pilot’s improper decision to approach the airport and enter a low altitude hover with a gusting quartering tailwind, which resulted in a loss of tail rotor effectiveness during a turn at a low altitude.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CEN21LA153
- Event ID
- 20210309102733
- Case number
- CEN21LA153
- 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 2021-02-25.
- API snapshot SHA-256: 01c645f9670b86777febb15f3276aa944d0417a5c08524d9808b200f0dcd9668; retrieved 2026-09-16T13:47:35.808Z.