LAX01LA079 · Hughes 369D
Hughes 369D · Accident: total loss of engine power (mechanical failure) en route
From Ely Airport Yelland Field (ELY) to Ely, NV
Event
- NTSB case
- LAX01LA079
- 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
Hughes 369D
- Aircraft type
- Hughes 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
- N8353F
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Ely Airport Yelland Field (ELY), Ely, NVTo Ely, NV
- 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 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
- En route · cruise
- 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
- Total loss of engine power (mechanical failure)
- 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
- Company maintenance personnel › Maintenance, replacement, improper
- Fluid, oil › Exhaustion
- Fluid, oil › Leak
- Lubricating system, oil quickdrain/drain plug › Activated
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
The single engine helicopter experienced a loss of engine power after the oil was inadvertently pumped overboard. A company mechanic replaced the torque gauge prior to the accident flight due to needle "bounce." The mechanic bled the torque system and reinstalled a radio that was removed to facilitate the work. During the radio installation, he inadvertently engaged the bleed valve, which is located behind the instrument panel, allowing oil to flow out of the engine from behind the instrument panel. While at 9,500 feet, the engine lost power and the pilot performed an autorotation landing to a field at the base of mountains. The pilot said he touched down smooth and light; however, the main rotor blades flexed and severed the tail boom. As a result of the accident, the operator rerouted the torque system bleed line toward the pilot's feet so that they could detect an inadvertent oil leak.
Probable cause
The mechanic's inadvertent activation of the bleed valve, which resulted in a loss of engine oil and loss of engine power while in cruise flight.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record LAX01LA079
- Event ID
- 20010125X00357
- Case number
- LAX01LA079
- 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, coordinates. 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: 69c408515efc8b8948512424b43652b93ab689bb477073692b90ccca37d1e493; retrieved 2026-09-22T12:12:52.500Z.