- Date
- May 12, 1989, 15:00 local (20:00 UTC)
- Place
- Shelbyville, TN
- Injuries
- 1 uninjured
- Damage
- Substantial damage
- Phase of flight
- Maneuvering
- Aircraft
- N908BBell 47
- Weather
- Visual (VMC) · Day
- Status
- Completed · report June 30, 1992
- Report
- Approved by Office Director
- FAA report
- 19890512011449A
- Case key
- 7844
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
Failure in the rotor drive system for unknown reasons. Contributing to the accident was the pilot's inability to perform an autorotation.
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
Investigation revealed that the helicopter was engaged in aerial application. During a procedure turn around there was a loud explosive noise & engine RPM exceeded rotor RPM. The pilot reduced the throttle & tried to enter an autorotation. Rotor RPM had decayed & a hard landing resulted. Most probable cause for the loss of rotor RPM was a disconnect between the engine & the main rotor for unknown reasons.
Aircraft
- Registration
- N908B
- Reported as
- Bell 47
- Category
- Helicopter
- Serial number
- 479
- Engine
- Lycoming VO-435-A1B, reciprocating
- Damage
- Substantial damage
- Flight
- Aerial application · Part 137
- Operator
- L. Lanier, doing business as Valley Flying Service
- Registered owner
- Unknown
- Airworthiness certificate
- Special, Restricted (Special)
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
- 44
- Certificate
- Commercial
- Airplane ratings
- Single-engine sea
- Medical
- Class 2, Valid Medical--no waivers/lim.
- Seat
- Right
- Flight hours
- 9,000 total · 1,000 in this make and model
Weather
- Conditions
- Visual (VMC) · Day
- Visibility
- 10 statute miles
- Lowest ceiling
- None
- Temperature
- 81 °F, dew point -0 °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 N908B · 7
Matched to the same aircraft by N-number and date.