- Date
- September 28, 1989, 07:45 local (11:45 UTC)
- Place
- Hudsonville, MI
- Injuries
- 1 minor
- Damage
- Substantial damage
- Phase of flight
- Enroute
- Aircraft
- N4028THiller UH-12E
- Weather
- Visual (VMC) · Day
- Status
- Completed · report June 30, 1992
- Report
- Approved by Office Director
- FAA report
- 19890928036999A
- Case key
- 14201
From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.
On this page
Probable cause
The fatigue failure of one of the tension-torsion pins.
Sequence of events
NTSB’s coding before 2008: each occurrence and phase of flight, and the causes and factors under it. The codes are defined in NTSB’s coding manual.
Analysis
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.
Aircraft
- Registration
- N4028T
- Reported as
- Hiller UH-12E
- Category
- Helicopter
- Serial number
- 5097
- Airframe hours
- 1,197
- Engine
- Lycoming VO-540-C2A, 305 horsepower, reciprocating
- Damage
- Substantial damage
- Flight
- Aerial application · Part 137
- Registered owner
- Byron Ag Aviation, Inc.
- Airworthiness certificate
- Standard, Normal
- Last inspection
- Annual · February 18, 1989 · 77 hours before
- Departed
- NONE · Byron Center, MI
- Destination
- NONE · Hudsonville, MI
Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.
Flight crew
As NTSB recorded them. NTSB leaves out names.
- Role
- Pilot
- Age
- 42
- Certificates
- Airline transport, Flight instructor
- Airplane ratings
- Single-engine land
- Instrument ratings
- Airplane, Helicopter
- Medical
- Class 1, Valid Medical--no waivers/lim.
- Seat
- Center
- Flight hours
- 8,900 total · 220 in this make and model · 8,800 as pilot in command · 120 in the last 90 days · 34 in the last 30 days · 1 in the last 24 hours
Weather
- Conditions
- Visual (VMC) · Day
- Wind
- 210° at 7 knots
- Visibility
- 15 statute miles
- Lowest ceiling
- None
- Temperature
- 46 °F, dew point 39 °F
- Altimeter
- 30.00 inHg
- Observed at
- GRR, 18 nm away
FAA reports on this event · 1
The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.
Other investigations on N4028T · 1
Matched to the same aircraft by N-number and date.