# NTSB LAX90LA321: Brantly Helicopter B-2B, N2159W, Novato, CA, September 12, 1990

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: September 12, 1990, 16:03 local (23:03 UTC)
- Place: Novato, CA
- Coordinates: 38.099189, -122.629005 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=38.0992&lon=-122.6290&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 2 uninjured
- Status: Completed, report February 12, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 26920
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX90LA321
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/26920/pdf
- Page: https://openairdocs.org/ntsb/LAX90LA321

## Probable cause

THE PILOT'S IMPROPER EXECUTION OF THE AUTOROTATION. CONTRIBUTING TO THIS ACCIDENT WAS THE EXCESSIVE SINK RATE AND MISJUDGING OF THE ALTITUDE.

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- In flight collision with terrain/water, descent
  - autorotation - improper, pilot in command (cause)
  - proper descent rate - excessive, pilot in command (cause)
  - altitude - misjudged, pilot in command (cause)

## Analysis

WHILE ON AN ADDED RATING FLIGHT TEST THE FAA DESIGNATED EXAMINER CALLED FOR A SIMULATED ENG FAILURE. THE PRIVATE PILOT APPLICANT IMMEDIATELY LOWERED THE COLLECTIVE AND BEGAN A 180 DEGREE TURN INTO THE WIND. WHEN THE HELICOPTER WAS ABOUT 160 DEGREES INTO THE TURN AND WAS ABOUT 50 FEET ABOVE THE GROUND THE PILOT BEGAN THE POWER RECOVERY BUT DUE TO THE HIGH SINK RATE THE SKIDS STRUCK THE SOFT DIRT OF A FRESHLY PLOWED FIELD CAUSING THE HELICOPTER TO ROLL TO THE RIGHT AND THE MAIN ROTOR BLADES TO STRIKE THE GROUND.

## Aircraft

- Registration: N2159W (not matched to a registry record)
- Reported make and model: Brantly Helicopter B-2B
- Category: Helicopter
- Serial number: 320
- Engines: LYCOMING IVO-360-A1A 180 horsepower reciprocating
- Damage: Substantial damage
- Flight: Instructional, Part 91
- Operator: Rosenberg, Kenneth P.
- Registered owner: Rosenberg, Kenneth P
- Airport: 056, Gnoss

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 49; private; medical: class 3, unknown; seat: right; flight hours: 338 total, 61 in this make and model, 234 as pilot in command, 15 in the last 90 days, 7 in the last 30 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 270° at 15 knots
- Lowest ceiling: none
- Temperature: -0 °F, dew point -0 °F

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

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