Bell 206B N111PM

Summary

On 24 December 2023 at about 06:30 local time, a Bell 206B registered N111PM was involved in an accident near El Centro, 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

24 December 2023 at 06:30

Classification

Accident

Location

El Centro, California, United States

Coordinates

32.9406, -115.3187

Aircraft

Bell 206B

Registration

N111PM

Category

Helicopter

Year built

1975

Engines

1

Operator

Not recorded

Operating rule

Part 137: Agricultural

Purpose of flight

Aerial Application

Phase of flight

Not recorded

Route

Brawley → Unknown

Aircraft damage

Substantial

Weather

VMC

Light

Night

NTSB number

WPR24LA067

Nobody was injured.

An in-flight failure of the engine-to-transmission driveshaft due to a fatigue fracture of the forward-most flex plate in the forward KAflex coupling that resulted from a loose bolt attachment between the flex plate and the forward driveshaft coupling. Contributing to the accident was maintenance personnel’s failure to identify the condition and remove the KAflex driveshaft for repair as specified by the manufacturer.

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

Read the full NTSB narrative

The pilot was flying in night visual flight rules (VFR) conditions about 100 ft above ground level (agl), toward an intended application site for agricultural pesticides, when the helicopter began to make a loud noise and vibrate. Unsure if the helicopter had lost rotor rpm or not, the pilot lowered the collective and initiated a run-on landing to a field. Postaccident examination of the helicopter’s airframe and engine revealed that the forward-most flex plate of the forward flex coupling on the KAflex driveshaft assembly was fractured. No evidence of additional preaccident mechanical malfunction or failure that would have precluded normal operation was observed. Fracture analysis revealed that the flex plate failed due to a fatigue fracture resulting from a loose attachment between the flex plate and the forward driveshaft fitting. Multiple areas of missing or replacement torque paint were observed throughout the KAflex driveshaft assembly’s joints. It is likely that the joints had either slipped or been manually disturbed before the non-original torque paint was applied, which would have been cause for the driveshaft assembly to be removed and shipped to the manufacturer. However, no evidence of the driveshaft’s removal after visual confirmation of joint slippage or disturbance was recorded in the aircraft maintenance logs.

Quoted verbatim from the NTSB record.