WPR24LA243 · McDonnell Douglas Helicopter 369E
Heliventure McDonnell Douglas Helicopter 369E · Accident: loss of tail rotor effectiveness while maneuvering
Event
- NTSB case
- WPR24LA243
- 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
McDonnell Douglas Helicopter 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
- N473E
- Operator
- Heliventure
- Onboard fatalities
- Unknown
- Route
- From not recordedTo not recorded
- Aircraft age
- About 33 years (built 1991)
- 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 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
- Aircraft › Aircraft propeller/rotor
- Environmental issues › Conditions/weather/phenomena
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
The sightseeing helicopter pilot made a slow, high-powered maneuver near a canyon tour site with three passengers on board in light gusting wind conditions. As the pilot tried to fly away from the area, an uncommanded right yaw occurred. The pilot applied full left pedal control, but the helicopter maintained its right yaw. Shortly after, the low rotor rpm audio warning sounded, and the temperature caution light flashed. The pilot performed a low-level autorotation, and the right yaw stopped, but the helicopter landed hard and bounced. The left skid separated, and the helicopter slid forward, balanced on the right skid. The pilot then departed back to the operator’s base airport and made an emergency landing on one skid, at which time the passengers safely disembarked. Shortly after, the pilot relocated the helicopter to an open grass area at the airport to shut down the helicopter, after which the helicopter came to rest on its side and the drivetrain sustained substantial damage. The pilot reported a possible tail control rigging issue; however, postaccident examination of the 4-bladed tail rotor assembly and the airframe revealed no preimpact mechanical anomalies. Flight control and drivetrain continuity were confirmed from the cockpit to all main and tail rotor flight control surfaces. Conditions reported by the pilot showed that he was operating at a high density altitude with a high gross weight while the helicopter was in a low-speed, high-powered, descending maneuver. As such, the pilot’s maneuvering was in an environment and flight profile that was conducive to the onset of loss of tail rotor effectiveness (LTE). According to the manufacturer and FAA Advisory Circular (AC) 90-95, the 4-bladed tail rotor assembly configuration is susceptible to LTE while operating with a low airspeed (typically below translational speed) with high power setting, and near or above maximum gross weight. It is likely that the pilot flew a flight profile that resulted in an uncommanded rapid yaw due to LTE, which was only mitigated by a low-altitude autorotation.
Probable cause
The pilot’s low-speed, high-power maneuvering in high density altitude and near maximum gross weight, which resulted in an uncommanded right yaw due to a loss of tail rotor effectiveness and a subsequent hard landing.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record WPR24LA243
- Event ID
- 20240715194698
- Case number
- WPR24LA243
- 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: investigation status, coordinates, cause areas. 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: 20c77d92d1570e3c3ad3fbf01c8faaca34d601de0d5f4bba03ba82659052a4f6; retrieved 2026-09-16T19:02:45.600Z.