- Date
- April 4, 1990, 13:58 local (20:58 UTC)
- Place
- La Verne, CA
- Injuries
- 2 uninjured
- Damage
- Substantial damage
- Phase of flight
- Landing
- Aircraft
- N739BBell 47G
- Weather
- Visual (VMC) · Day
- Status
- Completed · report March 12, 1993
- Report
- Approved by Office Director
- FAA report
- 19900404013889A
- Case key
- 26770
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 helicopter's rotor system being allowed to underspeed as a result of improper use of flight controls by the dual student; improper supervision by the certified flight instructor; and delayed remedial action by the certified flight instructor which allowed the in flight collision with the runway.
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
According to the instructor pilot, the aircraft began to vibrate during termination of a power recovery autorotation. He stated that when the commercially rated student pilot applied power, the engine developed power, but the rotor RPM decayed. The aircraft collided with the runway. The instructor pilot was late in taking the controls and recovering the aircraft. An FAA airworthiness inspector examined the helicopter and found no pre-impact mechanical malfunctions or failures.
Aircraft
- Registration
- N739B
- Reported as
- Bell 47G
- Category
- Helicopter
- Serial number
- 85
- Engine
- Lycoming VO-435, 220 horsepower, reciprocating
- Damage
- Substantial damage
- Flight
- Instructional · Part 91
- Operator
- Airborne Helicopters
- Airport
- POC · Brackett, runway 26R, 3,661 × 75 ft, asphalt
Flight crew
As NTSB recorded them. NTSB leaves out names.
- Role
- Pilot
- Age
- 40
- Certificates
- Commercial, Flight instructor
- Airplane ratings
- Single-engine land, Multi-engine land
- Instrument ratings
- Airplane
- Medical
- Class 2, Valid Medical--no waivers/lim.
- Flight hours
- 2,000 total
Weather
- Conditions
- Visual (VMC) · Day
- Wind
- 30° at 5 knots
- Visibility
- 12 statute miles
- Lowest ceiling
- 2,500 ft broken
- Temperature
- 64 °F, dew point 55 °F
- Observed at
- ONT, 12 nm away
FAA reports on this event · 1
The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.