WPR11LA244 · Hiller UH-12E
Alpine Helicopter Service Hiller UH-12E · Accident: loss of control in flight while maneuvering
From Lodi Airpark (l53) to Lodi Airpark (l53)
Narrative check · The NTSB narrative appears to contradict this record's departure or destination. Values are shown as recorded, not corrected; compare with the narrative.
Event
- NTSB case
- WPR11LA244
- 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
Hiller UH-12E
- Aircraft type
- Hiller UH-12
- 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
- N68012
- Operator
- Alpine Helicopter Service
- Onboard fatalities
- Unknown
- Route Narrative disagrees
- From Lodi Airpark (l53)To Lodi Airpark (l53)
- 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 137: Agricultural
- 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 · low-altitude flying
- 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 control in flight
- Also codedOther events the NTSB coded in the sequence, such as a wire strike after a loss of power. Flight Findings uses them for its kinds of event. Glossary
- Tree(s)
- 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
- Environmental issues › Physical environment
- Personnel issues › Psychological
- Personnel issues › Task performance
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The pilot initially reported that he was conducting low level agricultural drying of cherry trees when the tail rotor contacted a tree during a turn. He felt a shake or vibration through the controls and looked for a place to land. He was maneuvering the helicopter towards a road when the helicopter experienced a full left yaw. The pilot applied full right pedal to counter the yawing motion and entered autorotation through the trees to the ground. Subsequently the pilot revised his statement saying that the skids of his helicopter were at least 10-15 feet above the tallest tree when he felt a shake or vibration through the controls. Postaccident examination of the airplane by a mechanic and a FAA inspector found continuity between the tail rotor and the linkages through the drive train which lead to the main transmission. Control system continuity was also established. The tail boom near the tail rotor transmission was twisted clockwise, shearing the aluminum, which is consistent with a tail rotor imbalance condition. Tail rotor blade #1 was sheared off about one quarter of the distance between the blade root and the blade tip, and rotor blade #2 had compression deformation of the trailing edge near the blade root. The sheared off portion of tail rotor blade #1 was located in the orchard. Visual inspection found a circular impact deformation in the leading edge at the blade tip, separation of the blade tip weight from the blade, deformation of the blades surface area, and compression bending of the blade's trailing edge. The damage to blade #1 was consistent with an impact to a tree limb.
Probable cause
The pilot's failure to maintain clearance from obstacles.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record WPR11LA244
- Event ID
- 20110602X00259
- Case number
- WPR11LA244
- 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. 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: f7cf9142b799014a350bebfcb1d2542b3e72e36733af649a1ff8a838528dad20; retrieved 2026-09-15T16:14:04.284Z.