SEA07LA041 · Hughes 369D
Highline Helicopters Hughes 369D · Accident: loss of engine power while maneuvering
From Lyman, WA to Lyman, WA
Event
- NTSB case
- SEA07LA041
- 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
- N1088G
- Operator
- Highline Helicopters
- Onboard fatalities
- Unknown
- Route
- From Lyman, WATo Lyman, WA
- 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 out of ground effect
- 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 engine power
- 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 › Flight into known adverse weather, intentional
- Turboshaft engine › Ice ingestion
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
The pilot made two long-line movements of cargo in light dry snow. After completing the second load, the pilot noticed that the snow had turned wet and heavy, and he told the ground crew that he was leaving the area. As he turned to depart the area, one of the ground crew radioed him and said that he was going to pass near one of the loads, and suggested that he pick it up. The pilot maneuvered toward the load, and entered into a hover to swing the long-line hook forward. Just as he entered the hover, the engine lost power, and the pilot delayed his emergency autorotation to allow the ground crew person to find cover. Because the rotor system energy decayed during the pilot's intentional delay of the autorotation, he was unable to control the descent, and the helicopter settled onto the terrain at an excessive rate of descent. The pilot stated that when he changed the angle of attack to put the hook in the right location, he believes a layer of wet snow and ice crystals lifted off the canopy and entered the engine particle separator, leading to a loss of engine power. A postaccident inspection did not reveal evidence of any system malfunction or anomaly.
Probable cause
The pilot's intentional flight into adverse weather conditions, which resulted in a loss of engine power during hover due to snow and ice ingestion. Factors associated with the accident are the pilot's delayed remedial actions, and snow and icing conditions.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record SEA07LA041
- Event ID
- 20070123X00085
- Case number
- SEA07LA041
- 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: dab0dd9bdad28870073070e9c4d6ce975aff0370230f71a5f1de6df9c3cf8a26; retrieved 2026-09-21T08:51:59.929Z.