DEN01LA154 · McDonnell Douglas 369E
Omni Aviation Services McDonnell Douglas 369E · Accident: loss of control in flight while maneuvering
From Kemmerer, WY (no airport) to an unrecorded destination
Event
- NTSB case
- DEN01LA154
- 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
McDonnell Douglas 369E
- Aircraft type
- McDonnell Douglas 369
- 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
- N440TJ
- Operator
- Omni Aviation Services
- Onboard fatalities
- Unknown
- Route
- From Kemmerer, WY (no airport)To not recorded
- Aircraft age
- Not recorded
- 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 133: Rotorcraft Ext. Load
- 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
- First occurrenceThe 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
- Pilot in command › Loss of tail rotor effectiveness, encountered
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The pilot was transporting bags of seismic equipment by long line to a remote site. While he hovered into the wind waiting for a flagger, the helicopter was struck by a wind gust and started turning right. The pilot applied left pedal, but was unable to stop the rotation. The helicopter struck terrain, breaking off both skid legs, tail rotor blades, and tail rotor gearbox. FAA's Advisory Circular 90-95 defines the loss of tail rotor effectiveness as "a critical, low-speed aerodynamic flight characteristic that can result in an uncommanded rapid yaw rate which does not subside of its own accord and, if not corrected, can result in the loss of aircraft control." Some of the conditions conducive to LTE include (1) a high power setting, (2) low airspeed, and (3) a tailwind or left crosswind.
Probable cause
loss of tail rotor effectiveness while hovering. A contributing factor was the wind gust.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record DEN01LA154
- Event ID
- 20010907X01895
- Case number
- DEN01LA154
- Dataset
- historical-pre2008
- Source SHA-256
- 89e2df6d848e7ab3b42e7d7c7a03ff403303057a26ca04c95b3ea67201c3ce74
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: d6113ea075d7f995ef2601db4b3cd201821ce87f526923a8907886e905956790; retrieved 2026-09-22T11:35:41.751Z.