Hiller UH-12E N4028T

Summary

On 28 September 1989 at about 11:45 local time, a Hiller UH-12E registered N4028T was involved in an accident near Hudsonville, Michigan, United States. One person was on board and one had minor injuries. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

28 September 1989 at 11:45

Classification

Accident

Location

Hudsonville, Michigan, United States

Coordinates

42.8609, -85.8594

Aircraft

Hiller UH-12E

Registration

N4028T

Category

Helicopter

Engines

1

Operator

Not recorded

Operating rule

Part 137: Agricultural

Purpose of flight

Aerial Application

Phase of flight

Not recorded

Route

Byron Center → Hudsonville

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

CHI89DEM09

1 person had minor injuries.

THE FATIGUE FAILURE OF ONE OF THE TENSION-TORSION PINS.

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

Read the full NTSB narrative

APPROXIMATELY 10 MINUTES AFTER TAKEOFF AT AN ALTITUDE OF 300 FT AGL AND AN AIRSPEED OF 60 KTS, THE PILOT EXPERIENCED A SEVERE VIBRATION AND A DECREASE IN RESPONSE TO CONTROL INPUTS. THE PILOT ENTERED AN AUTOROTATION AND WHEN APPROXIMATELY 10 - 15 FT AGL, THE TAIL BOOM WAS SEPARATED BY THE MAIN ROTOR. THE HELICOPTER THEN DESCENDED, NOSE FIRST, TO TERRAIN IMPACT. INSPECTION REVEALED A TENSION-TORSION PIN HAD FAILED AT THE DRAG BRACE BOLT HOLE. PRE-EXISTING CRACKS WERE FOUND EXTENDING FROM THE PIN SHANK TO THE BOLT HOLE.

Quoted verbatim from the NTSB record.