Bell OH58A N901XV

Summary

On 31 July 2020 at about 03:45 local time, a Bell OH58A registered N901XV, operated by A Farmer Service Corp., was involved in an accident near Holtville, California, United States. One person was on board and one had minor injuries. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

31 July 2020 at 03:45

Classification

Accident

Location

Holtville, California, United States

Coordinates

32.7631, -115.2769

Aircraft

Bell OH58A

Registration

N901XV

Category

Helicopter

Engines

1

Operator

A Farmer Service Corp.

Operating rule

Part 137: Agricultural

Purpose of flight

Aerial Application

Phase of flight

Not recorded

Route

Imperial → Imperial

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

WPR20LA247

1 person had minor injuries.

The total loss of engine power due to the decoupling of the engine's turbine and compressor sections, which resulted from improper maintenance.

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

Read the full NTSB narrative

The pilot was performing agricultural operations in the helicopter. He made a normal takeoff and completed three passes over the field being sprayed. As he approached wires, the pilot maneuvered the helicopter into a climb and prepared to make a fourth pass. As he was completing a left turn back to the field, the engine experienced a total loss of power. He performed an autorotation, and during the touchdown, the helicopter collided with haystacks. Postaccident examination of the engine revealed extensive damage to the aft end of the compressor, the spur adapter gearshaft, and the compressor splined adapter. A material analysis revealed that the compressor splined adapter had failed in fatigue. The failure decoupled the turbine section from the compressor section resulting in the loss of engine power. The compressor splined adapter failed due to a misalignment of the engine's centerline shafting components that resulted from two separate improper maintenance actions. The first improper maintenance action was the installation of an incorrect number of shims at the interface between the rear compressor diffuser and the accessory gearbox. The second improper maintenance action was the installation of an incorrect compressor splined adapter; the impeller had been machined to fit a larger diameter (-3) compressor splined adapter: however, a smaller diameter (-1) adapter was installed.

Quoted verbatim from the NTSB record.