SEA98FA104 · Garlick UH-1H
Garlick UH-1H · Accident: total loss of engine power (mechanical failure) while maneuvering
From Coeur d'Alene, ID to an unrecorded destination
Event
- NTSB case
- SEA98FA104
- 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
- 0
- 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
Garlick UH-1H
- Aircraft type
- Garlick UH-1
- 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
- N869W
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Coeur d'Alene, IDTo 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
- 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
- Reduction gear assembly, reduction gear › Fatigue
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The pilot stated that he heard a loud metallic bang coming from the rear of the aircraft, followed immediately by a loss of power. He elected not to auto-rotate to a landing at the log-landing because of personnel in the vicinity, so he initiated an approach to a logging road adjacent to the log-landing. He landed with skids level, no power, and very low rotor rpm, but felt that he had the road made. After touching down, the helicopter rocked backward and rolled over on its left side. The engine was still running, and the pilot shut it down with the fuel valve. During the course of engine disassembly and inspection, output reduction gearbox damage was found to be consistent with a number one planet gearshaft separation caused by fatigue initiating at the outside diameter of the gear shaft within the shaft/gear web shoulder fillet radius. Laboratory analysis of the remnants of the number one planet gear noted that a cross section through the apparent fatigue origin did not exhibit evidence of material defects; however the fatigue initiation area was obscured as a result of secondary damage. The outer diameter of the planet gear shaft was found to have been plated with chromium or nickel and the case hardness of the carburized case on the planet gear was below that specified by the manufacturer. Investigation determined that none of the three planet gears in this engine were of OEM manufacture. Plating of the planet gear is not an authorized repair procedure, and no military repair procedure was identified authorizing this type of repair.
Probable cause
Fatigue failure of a reduction drive planetary gear. Factors include an unapproved part and plating process, and uneven terrain at the emergency landing site.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record SEA98FA104
- Event ID
- 20001211X10418
- Case number
- SEA98FA104
- 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: c786af48e8ebd66b81a008e8698581a9c73ca30fbdf4905c9c14aec610b8bdc1; retrieved 2026-09-22T17:39:08.563Z.