- Date
- December 20, 1989, 08:20 local (14:20 UTC)
- Place
- Creola, AL
- Injuries
- 1 uninjured
- Damage
- Substantial damage
- Phase of flight
- Maneuvering
- Aircraft
- N106SRBell TH-1
- Weather
- Visual (VMC) · Day
- Status
- Completed · report October 7, 1992
- Report
- Approved by Office Director
- FAA report
- 19891220052119A
- Case key
- 8191
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 loss of engine power due to a #21 bearing failure. The bearing failed as a result of inadequate maintenance. A factor in the accident was the pilot operating the helicopter within the avoid operating envelope.
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 engine failed while the pilot was hovering at 110 ft during an external load operation. The pilot released the load and autorotated into a swampy area. Engine teardown showed evidence of seizure and heavy wear at the #21 bearing assembly roller/shaft interface. Metallurgical exam revealed a breakdown of the tungsten carbide and cobalt coating repair. The detonation gun (dgun) repair buildup on the bearing/seal journal, seo T53-LO-R0035, was used in 1969, and canceled in 1970. The procedure was not approved or practiced by Lycoming, and the manufacturer recommended that parts repaired iaw the seo not be installed in engines. The pilot was operating within the 'avoid operation' area of the airspeed velocity chart.
Aircraft
- Registration
- N106SR
- Reported as
- Bell TH-1
- Category
- Helicopter
- Serial number
- 157806
- Airframe hours
- 8,403
- Engine
- Lycoming T53-L13B, 1,100 horsepower, turbo shaft
- Damage
- Substantial damage
- Flight
- Other work use · Part 91
- Registered owner
- Scott Paper Company
- Airworthiness certificate
- Special, Restricted (Special)
- Last inspection
- 100 hour · November 29, 1989 · 80 hours before
- Departed
- Mt Vernon, AL
- Destination
- Mobile, AL
Flight crew
As NTSB recorded them. NTSB leaves out names.
- Role
- Pilot
- Age
- 42
- Certificate
- Commercial
- Airplane ratings
- Single-engine land
- Instrument ratings
- Helicopter
- Medical
- Class 1, Valid Medical--no waivers/lim.
- Flight hours
- 15,534 total · 3,629 in this make and model · 296 in the last 90 days · 56 in the last 30 days · 3 in the last 24 hours
Weather
- Conditions
- Visual (VMC) · Day
- Wind
- 360° at 10 knots
- Visibility
- 10 statute miles
- Lowest ceiling
- 3,000 ft overcast
- Temperature
- 39 °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.