- Date
- October 3, 1994, 15:20 local (20:20 UTC)
- Place
- Decatur, IL
- Injuries
- 2 minor
- Damage
- Substantial damage
- Phase of flight
- Enroute
- Aircraft
- N5193BBell 47G2
- Weather
- Visual (VMC) · Day
- Status
- Completed · report June 19, 1995
- Report
- Approved by Office Director
- FAA report
- 19941003032719A
- Case key
- 9770
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 failure of the roller springs in the freewheeling unit of the transmission which caused the unit to disengage.
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 pilot stated that after completing a line patrol, he made a climbing left turn to return to the airport. At approximately 50 to 75 feet above the ground, the pilot heard a strange sound, the engine began to overspeed, and the helicopter began to descend. He lowered the collective and placed the helicopter into an autorotation to make a forced landing on a road. The helicopter touched down hard and was damaged. A postaccident investigation revealed 13 of 32 roller springs inside the freewheeling unit of the transmission were broken causing the unit to become disengaged.
Factual narrative
On October 3, 1994, at 1520 central daylight time, a Bell 47G2, N5193B, sustained substantial damage following a loss of engine power and subsequent forced landing on a road near Decatur, Illinois. The commercial pilot and passenger reported minor injuries. The local 14 CFR Part 91 flight operated in visual meteorological conditions without a flight plan.
The pilot stated he began a climbing left turn to return to Decatur Airport after completing a line patrol. At approximately 50 to 75 feet above the ground, the pilot stated he heard a strange sound, the engine began to overspeed, and the helicopter began to descend. He lowered the collective and placed the helicopter into an autorotation to make a forced landing. The helicopter landed hard on a road.
The helicopter logbook shows the last inspection was a 100 hour inspection performed on September 23, 1994. The helicopter has logged 33 hours since the inspection.
A postaccident examination of the engine and transmission revealed 13 of the 32 roller springs were broken inside the freewheeling unit of the transmission. Eight of the 13 broken springs were located in the 270 degree to 360 degree quadrant; a total of 10 were located in the 180 degree to 360 degree quadrant; and the remaining three were dispersed throughout the one degree to 180 degree quadrant. All pieces of the broken springs were self-contained within the freewheeling unit. There were no discrepancies noted to any other component.
Aircraft
- Registration
- N5193B
- Reported as
- Bell 47G2
- Category
- Helicopter
- Serial number
- 2174
- Airframe hours
- 6,413
- Engine
- Lycoming VO-435-A1F, 150 horsepower, reciprocating
- Damage
- Substantial damage
- Flight
- Aerial observation · Part 91
- Registered owner
- Fostaire Helicopters
- Airworthiness certificate
- Standard, Normal
- Last inspection
- 100 hour · September 23, 1994 · 33 hours before
- Departed
- DEC · IL
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
- 30
- Certificates
- Commercial, Flight instructor
- Instrument ratings
- Helicopter
- Medical
- Class 2, Valid Medical--no waivers/lim.
- Seat
- Left
- Flight hours
- 3,500 total · 3,450 as pilot in command · 100 in the last 90 days · 40 in the last 30 days · 5 in the last 24 hours
Weather
- Conditions
- Visual (VMC) · Day
- Wind
- 80° at 11 knots
- Visibility
- 10 statute miles
- Lowest ceiling
- None
- Temperature
- 70 °F
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 N5193B · 6
Matched to the same aircraft by N-number and date.