Bell 206B N7929J

Summary

On 23 August 1997 at about 14:00 local time, a Bell 206B registered N7929J was involved in an accident near Oak Grove, Louisiana, 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

23 August 1997 at 14:00

Classification

Accident

Location

Oak Grove, Louisiana, United States

Coordinates

32.8605, -91.3899

Aircraft

Bell 206B

Registration

N7929J

Category

Helicopter

Engines

1

Operator

Not recorded

Operating rule

Part 133: Rotorcraft Ext. Load

Purpose of flight

Other Work Use

Phase of flight

Not recorded

Route

Cameron → Unknown

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

FTW97LA326

Nobody was injured.

The disconnect of the #5 tail rotor drive segment due to the debonding of the joint between the shaft tube and the flange fitting. Factors were the improper bead blasting of the tail rotor drive segment by an unknown maintenance personnel, and the lack of altitude and suitable terrain for the forced landing.

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

Read the full NTSB narrative

During an external load operation, the pilot was hovering the helicopter at about 60 feet above the boat, when the helicopter began to 'spin' to the right. He 'rolled off the throttle' and the spin stopped. He then maneuvered the helicopter to the right as it descended in an effort to clear the boat; however, the main rotor blades struck the front of the boat. Subsequently, the helicopter settled into the water and sank. Examination of the tail rotor drive system revealed that the #5 tail rotor drive shaft segment P/N 206-040-931-9 had separated at the bonded joint between the shaft tube and the flange fitting. Examination of this tail rotor drive segment by a metallurgist revealed that the separated joint revealed evidence of pitting which was indicative of plastic blast media impingement and the remaining adhesive had the consistency of powder/talc with no apparent structural integrity. According to the metallurgist the 'blast media impingement may effectively compromise the moisture barrier at the joint and allow the moist chloride environment to invade the joint and chemically degrade the adhesive.' Blast media impingement is not approved by Bell Helicopter.

Quoted verbatim from the NTSB record.