Hiller UH-12E N3004T

Summary

On 22 April 2002 at about 18:30 local time, a Hiller UH-12E registered N3004T, operated by Sundance Helicopters, Inc., was involved in an accident near Goshen, Oregon, United States. 3 people were 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

22 April 2002 at 18:30

Classification

Accident

Location

Goshen, Oregon, United States

Coordinates

44.0167, -123.0217

Aircraft

Hiller UH-12E

Registration

N3004T

Category

Helicopter

Engines

1

Operator

Sundance Helicopters, Inc.

Operating rule

Part 91: General Aviation

Purpose of flight

Aerial Observation

Phase of flight

Not recorded

Route

Eugene → Creswell

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

SEA02LA073

Nobody was injured.

The failure of company maintenance personnel to identify and replace/repair the degraded exhaust stack. Contributing factors were the mis-rigged carburetor heat control and the pilot's failure to maintain appropriate rotor RPM. Additional contributing factors were trees and water.

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

Read the full NTSB narrative

While in cruise flight the engine experienced a total loss of power in the Hiller UH-12E rotorcraft. In an attempt to avoid a water landing he maneuvered over trees and then ran out of rotor RPM landing hard. Post crash examination revealed that the left hand exhaust stack tube inside the cylindrical stainless steel heat muffler was cracked and separated circumferentially in the vicinity of an old weld. The left side muffler was dedicated exclusively to providing engine heated air for carburetor heat application. The exhaust stack tube was observed to be thin and heat distorted and the circumferential split was noted to be in the vicinity of an old weld. The split in the tube allowed hot engine exhaust to duct directly to the carburetor via the carburetor heat plenum. Additionally, the carburetor heat valve within the plenum to the carburetor was found to be out of rig such that when carburetor heat was fully de-selected in the cockpit (FULL COLD), engine heated air was still partially flowing to the carburetor intake. A 100-hour inspection had been completed and signed off by company maintenance personnel 19.8 hours previous to the accident. Appendix D to Part 43 of the Federal Aviation Regulations requires each person performing an annual or 100-hours inspection to inspect (where applicable) components of the engine and nacelle group including exhaust stacks - for cracks, defects, and improper attachment.

Quoted verbatim from the NTSB record.