Hiller UH-12E accident near Stockton, California, June 1, 2011
On June 1, 2011 at about 11:20 pm local time, a Hiller UH-12E (helicopter), registered N68012, was substantially damaged in an accident during maneuvering (low-alt flying) near Stockton, California (Lodi Airport). It was an aerial application (crop spraying) flight under agricultural flying rules (Part 137). No one was hurt; 1 person was on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The pilot's failure to maintain clearance from obstacles.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- June 1, 2011 · about 11:20 pm local time
- Place
- Stockton, California · Lodi Airport · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Hiller UH-12E · all UH-12Es on the register
- Registration
- N68012 · no longer on the register · serial 1500
- Damage
- Substantial damage
- Flight
- Aerial application (crop spraying) flight · agricultural flying rules (Part 137)
The NTSB's narrative final · quoted from the NTSB record
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.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
What happened, in order
- Collision with terrain or object (not controlled flight into terrain) during maneuvering (low-alt flying)
- Loss of control in flight during maneuvering (low-alt flying) defining event
- Off-field or emergency landing during maneuvering (low-alt flying)
- Collision with terrain or object (not controlled flight into terrain) during landing (flare/touchdown)
The NTSB's findings
- cause Personnel issues › Psychological › Attention/monitoring › Attention › Pilot
- cause Personnel issues › Task performance › Use of equip/info › Aircraft control › Pilot
- cause Environmental issues › Physical environment › Object/animal/substance › Tree(s) › Response/compensation
- cause Personnel issues › Psychological › Attention/monitoring › Monitoring environment › Pilot
Pilot
- Certificate: commercial pilot
- Ratings: rotorcraft: helicopter
- Flight time: 2,382 hours in all; 1,375 in this make and model; 70 in the last 90 days; 27 in the last 30 days; 2,294 as pilot in command
- Last flight review: July 20, 2010
- Medical certificate: Class 2 (without waivers/limitations)
- Seat: ctr
- Injury: no injuries
The aircraft
- Airframe total time: 7,316 hours
- Last inspection: 100-hour inspection, March 11, 2011; 66 hours since
- Maximum gross weight: 2,800 lb
- Seats: 3
- Landing gear: fixed
- Engine: Lycoming V0-540 (piston); 0 hours total
- Operator: Alpine Helicopter Service, Inc.
The flight
- Departed from: l53 Lodi CA at 9:00 pm
- Destination: l53 Lodi CA
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: at 4 knots
- Visibility: 10 statute miles
- Sky: broken clouds at 9,000 ft; scat at 6,000 ft
- Temperature: 64°F (18°C), dew point 50°F (10°C)
- Altimeter: 29.92 inHg
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
Other NTSB records under N68012 the same tail number, which may have belonged to a different aircraft at the time
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.