Hiller UH-12E N752GB

Summary

On 10 November 1998 at about 17:00 local time, a Hiller UH-12E registered N752GB was involved in an accident near Marshall, Washington, United States. One person was on board and one died. The aircraft was destroyed. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

10 November 1998 at 17:00

Classification

Accident

Location

Marshall, Washington, United States

Coordinates

47.4307, -117.6202

Aircraft

Hiller UH-12E

Registration

N752GB

Category

Helicopter

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Other Work Use

Phase of flight

Not recorded

Route

Unknown → Keller

Aircraft damage

Destroyed

Weather

VMC

Light

Not Reported

NTSB number

SEA99FA013

1 person died.

The loss of the bolt that connects the lateral cyclic linkage push rod to the lower end of the upper firewall-mounted lateral cyclic linkage bellcrank, resulting in an uncontrolled descent into the terrain.

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

Read the full NTSB narrative

While climbing out after takeoff from the helicopter pad located at the pilot's residence/place of business, the bolt that connected the lower end of the upper-firewall lateral cyclic linkage bellcrank to its push rod separated from the aircraft. With the bolt missing from the control linkage, the necessary increase of the angle of attack (cyclic feathering) of the retreating blade (port blade) could not take place. Without this feathering, which is produced by the lateral position of the cyclic, the forward-moving blade (starboard side)produced considerably more lift than the retreating blade. This resulted in an uncontrolled roll to the left and an uncontrolled descent into the terrain.

Quoted verbatim from the NTSB record.