- Date
- June 10, 1984, 13:36 local (18:36 UTC)
- Place
- Merrimac, WI
- Injuries
- 1 fatal
- Damage
- Destroyed
- Phase of flight
- Approach
- Aircraft
- N93431Hiller UH-12E
- Weather
- Visual (VMC) · Day
- Status
- Completed
- Report
- Approved by Office Director
- Case key
- 12402
From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.
On this page
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
The acft crashed and burned after an in-flt explosion at about 75 ft AGL as the acft approached to land. The acft had experienced electrical problems of overheating generators and irregular voltage outputs on 2 previous occasions. The pltwas told after some repairs that if he smelled anything hot to pull the generator circuit breaker. Post-accident acft examination showed a condition of the voltage regulator which would have caused continuous charging of the battery. The generator showed signs of overheating and the battery had exploded away from the wreckage with the terminal poles meltedoff.
Aircraft
- Registration
- N93431
- Reported as
- Hiller UH-12E
- Category
- Helicopter
- Serial number
- 1768
- Airframe hours
- 1,837
- Engine
- Lycoming VO-4540-C2A, 305 horsepower, reciprocating
- Damage
- Destroyed
- Fire
- Both
- Flight
- Public aircraft · Part 91
- Registered owner
- Sauk County Emergency Govt.
- Airworthiness certificate
- Standard, Normal
- Last inspection
- Annual · December 19, 1983 · 4 hours before
- Departed
- Baraboo, WI
- Flight plan
- VFR
Flight crew
As NTSB recorded them. NTSB leaves out names.
- Role
- Pilot
- Age
- 38
- Certificates
- Commercial, Private
- Airplane ratings
- Single-engine land
- Medical
- Class 2, Valid Medical--no waivers/lim.
- Seat
- Left
- Toxicology
- Performed
- Flight hours
- 781 total · 567 in this make and model · 687 as pilot in command · 50 in the last 90 days · 25 in the last 30 days · 10 in the last 24 hours
Weather
- Conditions
- Visual (VMC) · Day
- Wind
- 230° at 23 knots, gusting 33
- Visibility
- 10 statute miles
- Lowest ceiling
- None
- Temperature
- 75 °F, dew point 57 °F
- Altimeter
- 29.00 inHg
- Observed at
- MSN, 30 nm away