Texas OH-13E/M74 N43921

Summary

On 22 February 2012 at about 19:25 local time, a Texas OH-13E/M74 registered N43921, operated by AG Air Inc, was involved in an accident near Farmington, California, United States. One person was on board and one was seriously injured. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

22 February 2012 at 19:25

Classification

Accident

Location

Farmington, California, United States

Coordinates

37.9308, -121.0286

Aircraft

Texas OH-13E/M74

Registration

N43921

Category

Helicopter

Year built

1977

Engines

1

Operator

AG Air Inc

Operating rule

Part 137: Agricultural

Purpose of flight

Aerial Application

Phase of flight

Not recorded

Route

Farmington → Farmington

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

WPR12LA115

1 person was seriously injured.

The in-flight separation of the wood portion of one main rotor blade while maneuvering at low level, the reason for which could not be determined because postaccident examination did not reveal any anomalies that would have precluded normal operation.

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

Read the full NTSB narrative

The commercial pilot was conducting aerial application flights in the single main rotor helicopter over a flat, level agricultural field. He had already conducted several uneventful flights that day in the helicopter on other portions of the same field. Just as the pilot completed a course reversal turn, the helicopter crashed in the field. The turn was the last thing the pilot remembered about the flight, and there were no eyewitnesses. Although the field was soft, and the helicopter's airspeed and altitude were low, the helicopter was extensively fragmented. One main rotor blade was found about 500 feet from the rest of the wreckage. That wood main rotor blade was essentially intact, except for the absence of its metal core and multiple linear, spanwise fastener tearouts at the root. The core was fracture-separated in overstress from its blade grip and was bent in a 270-degree arc. All these signatures were consistent with the wood blade, minus the core, separating from the rotor hub while in flight. The loss of the blade, and the subsequent imbalance to the rotor disc, induced vibratory loads that exceeded the structural strength of the helicopter, and resulted in extensive fragmentation of the helicopter before ground impact. No damage patterns consistent with a ground rotor strike were observed. The incompleteness of the maintenance records prevented the determination of the service history of the failed blade as well as its compliance with required inspections. The reason for the failure of the blade wood could not be determined.

Quoted verbatim from the NTSB record.