Hiller UH-12E N3324F

Summary

On 16 September 2008 at about 22:43 local time, a Hiller UH-12E registered N3324F, operated by Summit Helicopters Inc., was involved in an accident near Naruna, Virginia, 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

16 September 2008 at 22:43

Classification

Accident

Location

Naruna, Virginia, United States

Coordinates

37.0711, -79.0061

Aircraft

Hiller UH-12E

Registration

N3324F

Category

Helicopter

Engines

1

Operator

Summit Helicopters Inc.

Operating rule

Part 137: Agricultural

Purpose of flight

Aerial Application

Phase of flight

Not recorded

Route

Naruna → Naruna

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

NYC08LA318

Nobody was injured.

The fatigue failure of a main rotor blade drag strut.

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

Read the full NTSB narrative

While in straight and level flight, the pilot indicated that the helicopter began a "violent horizontal circular shake or wobble," and the main rotor rpm and began to decrease. The pilot entered an autorotation, turned the helicopter to the left to avoid trees, and touched down. During the forced landing, the tail rotor contacted the ground, and after the engine had been shut down, one of the main rotor blades contacted the tailboom. Post accident examination revealed that a main rotor blade drag strut had failed at the inboard threaded portion of the strut. Further examination revealed that a vibro-peen marked serial number was visible on the failed drag strut and that the drag strut had failed due to fatigue cracking that emanated from the root portion of the threads. The helicopter's maintenance records listed the failed drag strut as being a part number that should have had a life limit of 2,500 hours, but failed at 2,236 hours. Contrary to the helicopter manufacturer’s drawings, there was no part number on the failed drag strut, which put into doubt the actual hours of operation on the part.

Quoted verbatim from the NTSB record.