- Date
- July 10, 1990, 16:59 local (20:59 UTC)
- Place
- Teterboro, NJ
- Injuries
- 3 uninjured
- Damage
- Substantial damage
- Phase of flight
- Maneuvering
- Aircraft
- N73LMBell 206 B3
- Weather
- Visual (VMC) · Day
- Status
- Completed · report November 23, 1992
- Report
- Approved by Office Director
- FAA report
- 19900710027779A
- Case key
- 36539
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
Failed power turbine shaft. Factors in the accident were corrosion on the power turbine shaft and inadequate manufacturer's service bulletins.
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 was hovering when he heard a whine in the engine that increased in intensity. He saw torque fluctuations, heard an explosion, and autorotated to the ramp. Investigation showed the power turbine inner shaft failed in torsion due to corrosion on the inner surface and this allowed the third stage turbine wheel to go into overspeed and fail. Allison issued three service bulletins on the power turbine inner shaft. None of them used calendar time for compliance, only engine total time. The helicopter was 11 years old with 2146 hrs tt airframe and engine. The first scheduled work on the power turbine occurs at 3550 hrs.
Aircraft
- Registration
- N73LM
- Reported as
- Bell 206 B3
- Category
- Helicopter
- Serial number
- 2835
- Airframe hours
- 2,146
- Engine
- Allison 250-C20B, 317 horsepower, turbo shaft
- Damage
- Substantial damage
- Fire
- In-Flight
- Flight
- Part 135
- Operator
- Annapolis Aviation, doing business as Freedom Air
- Registered owner
- Annapolis Sea Going Institute
- Airworthiness certificate
- Standard, Normal
- Last inspection
- 100 hour · June 28, 1990 · 19 hours before
- Departed
- TEB
- Destination
- BWI · Baltimore, MD
- Flight plan
- VFR
- Airport
- TEB · Teterboro
Flight crew
As NTSB recorded them. NTSB leaves out names.
- Role
- Pilot
- Age
- 40
- Certificate
- Commercial
- Airplane ratings
- Single-engine land
- Instrument ratings
- Helicopter
- Medical
- Class 2, Valid Medical--no waivers/lim.
- Seat
- Right
- Flight hours
- 3,458 total · 3,000 in this make and model · 3,176 as pilot in command · 74 in the last 90 days · 47 in the last 30 days · 3 in the last 24 hours
Weather
- Conditions
- Visual (VMC) · Day
- Wind
- 300° at 10 knots
- Visibility
- 15 statute miles
- Lowest ceiling
- 10,000 ft broken
- Temperature
- 84 °F, dew point 63 °F
- Altimeter
- 29.00 inHg
- Observed at
- TEB
FAA reports on this event · 1
The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.