WPR13FA006 · Garlick Helicopters Inc UH-1H
Garlick Helicopters Inc UH-1H · Accident: part(s) separation from aircraft en route
From Grants Pass, OR to Grants Pass, OR
Event
- NTSB case
- WPR13FA006
- 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
Garlick Helicopters Inc 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
- N1577
- Operator
- Mccarty David M
- Onboard fatalities
- Unknown
- Route
- From Grants Pass, ORTo Grants Pass, OR
- Aircraft age
- About 47 years (built 1965)
- 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
- En route · cruise
- 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
- Part(s) separation from aircraft
- 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 propeller/rotor
Approximate · Coordinates from the NTSB case API, not marked as estimated; no uncertainty radius is established.
NTSB narrative
The pilot reported that he was in straight and level flight over mountainous, tree-covered terrain when he heard a loud noise followed by an abrupt jolt and right yaw. The pilot initiated a descent into a valley when he heard a second loud noise followed by severe vibrations and activation of the low rotor RPM horn. The helicopter continued to descend before it impacted the trees and ground below. During an on-scene examination, control continuity was established throughout the helicopter with the exception of the 90-degree gearbox and tail rotor assembly, which were separated from the helicopter and not found.
The gear box is positioned in between the tail rotor drive shaft and tail rotor assembly; it takes the input from the tail rotor drive shaft (through a quill assembly), and adjusts and transfers the energy to the tail rotor assembly. Because the gearbox and tail rotor separated in flight, the investigation was not able to examine them to determine their condition or their proper installation. However, the tail rotor gearbox input quill assembly, vertical driveshaft clamp, and two remaining gearbox attachment studs were removed for additional examination. Fatigue damage was noted along the fracture surface of the two gearbox attachment studs that were still attached to the vertical fin side of the mounting flange. The remaining four attachment holes were empty; however, helical rubbing marks were found around their perimeter along with an adjacent lip of deformed material, which is indicative of the studs being present at one point. Postaccident examination and a test run of the helicopter's engine revealed no anomalies that would have precluded normal operation.
The helicopter's most recent tail rotor gearbox inspection occurred about one month prior to the accident; however, the investigation could not determine if the fatigued area would have been included in the inspection, or whether any evidence of fatigue would have been detectable at the time of the inspection.
Probable cause
The separation of the tail rotor gearbox and tail rotor assembly as a result of fatigue to the tail rotor gearbox input quill assembly attachment studs.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record WPR13FA006
- Event ID
- 20121009X14815
- Case number
- WPR13FA006
- 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. 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: 06b2b95f01b737c89b369ae2f7b0c2f4c135ca141a229875a2d18792aa40a066; retrieved 2026-09-15T20:07:42.150Z.