Bell 47 N5120B
18 April 1990 · Oakdale, Minnesota, United States · Serious injuries
Summary
On 18 April 1990 at about 14:30 local time, a Bell 47 registered N5120B, operated by Twin City Helicopters, Inc., was involved in an accident near Oakdale, Minnesota, United States. One person was on board and one was seriously injured. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.
The record
- Date
- at 14:30
- Classification
- Accident
- Location
- Oakdale, Minnesota, United States
- Coordinates
- 45.0102, -93.0304
- Aircraft
- Bell 47
- Registration
- N5120B
- Category
- Helicopter
- Engines
- 1
- Operator
- Twin City Helicopters, Inc.
- Operating rule
- Part 137: Agricultural
- Purpose of flight
- Aerial Application
- Phase of flight
- Not recorded
- Aircraft damage
- Substantial
- Weather
- VMC
- Light
- Day
- NTSB number
- MKC90LA088
People
1 person was seriously injured.
| On board | Died | Serious | Minor | Uninjured |
|---|---|---|---|---|
| 1 | 0 | 1 | 0 | 0 |
Probable cause
A SLIPPING ROTOR DRIVE CLUTCH ASSEMBLY DUE TO IMPROPER MAINTENANCE BY COMPANY PERSONNEL. CONTRIBUTING FACTORS WERE STATIC WIRES IN THE PATH.
Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.
Read the full NTSB narrative
WHILE FERRYING THE HELICOPTER TO CONDUCT AN AERIAL APPLICATION OPERATION, THE PLT SAID THAT THE ENGINE BEGAN TO OVERSPEED. THE PLT ENTERED AN AUTOROTATION TO REDUCE ENGINE RPM, BUT HAD TO CLEAR POWER LINES. USING THE ROTOR RPM TO CLEAR THE POWER LINES, THE ROTOR RPM DECAYED AND THE ACFT DROPPED IN FROM ABOUT 50 TO 75 FEET AGL. POST ACCIDENT INVESTIGATION REVEALED A MALFUNCTIONING MAIN TRANSMISSION CENTRIFUGAL CLUTCH. THE POWERPLANT TEST FAILED TO REVEAL ANY MALFUNCTION. AN ANNUAL INSPECTION HAD BEEN PERFORMED 6 DAYS AND 4 HOURS OF FLIGHT TIME PRIOR TO THE ACCIDENT.
Quoted verbatim from the NTSB record.
Other Bell 47 accidents
| Date | Aircraft | Location | Operator | Outcome | Died |
|---|---|---|---|---|---|
| 1 Nov 1990 | Bell 47J-2 | Gatlinburg, Tennessee, United States | Pigeon Forge Helicopters, Inc. | Serious injuries | - |
| 4 May 1990 | Bell 47G | Riverside, California, United States | Riverside Air Service | Minor injuries | - |
| 16 Jun 1990 | Bell 47G-3B1 | Cedar Rapids, Iowa, United States | Badger Helicopters, Inc. | Fatal | 3 |
| 2 Apr 1990 | Bell 47G-3B-2 | Hillsboro, Oregon, United States | Western Helicopter Service | Serious injuries | - |
| 15 Nov 1990 | Bell 47-G3-B | Nantucket, Massachusetts, United States | Firefly, Inc. | No injuries | - |
| 2 Sep 1990 | Bell 47G-3B1 | Canon City, Colorado, United States | - | Minor injuries | - |
All 1,633 records for this type
Other accidents in this area
| Date | Aircraft | Location | Operator | Outcome | Died |
|---|---|---|---|---|---|
| 14 Jul 1990 | Piper PA-28-140 | Grand Marais, Minnesota, United States | - | Fatal | 3 |
| 1 Mar 1990 | Beechcraft B36TC | Inver Grove Hgt, Minnesota, United States | - | Fatal | 1 |
| 30 Aug 1990 | Beechcraft A23A | St Paul, Minnesota, United States | Black Sheep Flying Club | Fatal | 1 |
| 2 Sep 1990 | Cessna 172N | Pine City, Minnesota, United States | Aero Center One | Fatal | 1 |
| 7 Jan 1990 | Mancini ROTORWAY EXEC | Mountain Iron, Minnesota, United States | Mancini, Geno F. | No injuries | - |
| 7 Jan 1990 | Cessna 172 | St Cloud, Minnesota, United States | Anoka Flight Training | No injuries | - |