Bell UH-1B N204JB

Summary

On 6 September 2009 at about 13:05 local time, a Bell UH-1B registered N204JB, operated by Morten Jesse L, was involved in an accident near Arvilla, North Dakota, 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

6 September 2009 at 13:05

Classification

Accident

Location

Arvilla, North Dakota, United States

Coordinates

47.9178, -97.4944

Aircraft

Bell UH-1B

Registration

N204JB

Category

Helicopter

Engines

1

Operator

Morten Jesse L

Operating rule

Part 137: Agricultural

Purpose of flight

Aerial Application

Phase of flight

Not recorded

Route

Larimore → Unknown

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

CEN09LA565

1 person was seriously injured.

The aircraft owner/mechanic/pilot's installation of an improper tail boom assembly and the resulting fatigue failure of the tail boom's attach fittings.

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

Read the full NTSB narrative

The helicopter pilot reported that he heard a “crack” and a “bang” when he pulled up at the end of the field during the spray run. He stated the helicopter began spinning to the right as it gained altitude. He rolled off the throttle and was able to clear a row of trees at the end of the field. The helicopter impacted the terrain on one side of the tree line and the tail boom was located approximately 100 feet away, on the other side of the tree line. The examination revealed the tail boom’s upper left attach fitting contained fatigue fractures that originated at the upper and lower rivet holes. Corrosion was also present along the fractured surface. The tail boom’s upper right attachment bolt contained a fatigue fracture which had multiple origins. The tail boom’s lower right attach fitting fractured as a result of overload. The tail boom involved in this accident was installed on the helicopter on February 20, 2006, and had been removed from a UH-1F helicopter. The UH-1F tail boom is 23.8 inches longer than the UH-1B tail boom that was originally on the helicopter. The pilot/owner, who is an airframe and powerplant mechanic with inspection authority, performed this maintenance. There is no load data nor is there a Supplemental Type Certificate available for this installation.

Quoted verbatim from the NTSB record.