Hiller UH-12E N68012

Summary

On 1 June 2011 at about 23:20 local time, a Hiller UH-12E registered N68012, operated by Alpine Helicopter Service, Inc., was involved in an accident near Stockton, California, United States. One person was on board and nobody was injured. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

1 June 2011 at 23:20

Classification

Accident

Location

Stockton, California, United States

Nearest airport

Lodi Airport (L53)

Coordinates

38.0914, -121.3592

Aircraft

Hiller UH-12E

Registration

N68012

Category

Helicopter

Engines

1

Operator

Alpine Helicopter Service, Inc.

Operating rule

Part 137: Agricultural

Purpose of flight

Aerial Application

Phase of flight

Not recorded

Route

Lodi → Lodi

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

WPR11LA244

Nobody was injured.

The pilot's failure to maintain clearance from obstacles.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full 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.

Quoted verbatim from the NTSB record.