# NTSB LAX92LA006: Bentley Mongoose A, N7143K, Boulder City, NV, October 5, 1991

- Type: NTSB accident investigation
- Classification: Accident · Fatal · Limited investigation · Final report
- Date: October 5, 1991, 14:48 local (21:48 UTC)
- Place: Boulder City, NV
- Coordinates: 35.990245, -114.809921 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=35.9902&lon=-114.8099&mi=10
- Phase of flight: [Takeoff](https://openairdocs.org/ntsb-phases/300) (OpenAirDocs' grouping)
- Highest injury: Fatal
- Injuries: 2 fatal
- Status: Completed, report April 8, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 27468
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX92LA006
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/27468/pdf
- Page: https://openairdocs.org/ntsb/LAX92LA006

## Probable cause

THE PILOT'S SELECTION OF AN INADEQUATE TAKEOFF AREA WHICH WAS TOO SHORT FOR THE PREVAILING CONDITIONS.

## Sequence of events

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

- On ground/water encounter with terrain/water, takeoff - roll/run
  - terrain condition - berm
  - preflight planning/preparation - poor, pilot in command (cause)
  - unsuitable terrain or takeoff/landing/taxi area - selected, pilot in command (cause)

## Analysis

THE PLT'S MED CERT WAS EXPIRED & HE DID NOT HOLD A ROTORCRAFT CATEGORY RATING.  DRG AN EXAM OF THE WRECKAGE, STRONG ROTATIONAL SIGNATURES WERE EVIDENT ON BOTH THE PROP & MAIN ROTOR BLADES.  NO ACFT SYS ABNORMALITIES WERE FND DRG THE EXAM OF THE WRECKAGE.  WHEEL TRACKS & IMPACT GND SCARS WERE FND ON THE DRY LAKE BED SURFACE.  THREE TIRE TRACKS MATCHING THE DIMENSIONAL GEOMETRY OF THE LNDG GEAR WERE FND EXTENDING FOR A DISTANCE OF ABOUT 150 YDS. AN ADDITIONAL 15 YDS OF MAIN GEAR ONLY TRACKS WERE FND, WHICH TERMINATED AT A BERM.  HVY GOUGE MARKS WERE NOTED ON THE TOP OF THE BERM, WHICH MATCHED ALL 3 LNDG GEAR. ABOUT 105 YDS BEYOND THE BERM, A GND IMPACT CRATER WAS OBSERVED, FOLLOWED BY A DISTURBANCE IN THE DIRT WHICH CULMINATED IN THE GYROCOPTER WRECKAGE.  THE GYROCOPTER HAD NOT BEEN ISSUED AN AIRWORTHINESS CERTIFICATE IN ANY CATEGORY.

## Aircraft

- Registration: [N7143K](https://openairdocs.org/deregistered/N7143K-2011-05-18), registration cancelled 2011-05-18, S/N 1 (OpenAirDocs)
- Reported make and model: BENTLEY MONGOOSE A
- Registry model: [Bentley Richard F MONGOOSE A](https://openairdocs.org/model/bentley-richard-f-mongoose-a) (registry code 13015GS) (OpenAirDocs)
- Category: Gyroplane, amateur-built
- Serial number: 1
- Airframe hours: 113
- Engines: ROTAX 582 65 horsepower reciprocating
- Damage: Destroyed
- Flight: Personal, Part 91
- Operator: Bentley, Richard F
- Registered owner: Bentley, Richard F
- Airworthiness certificate: Special, Experimental (Special)
- Last inspection: Unknown, January 2, 2000
- Destination: NONE
- Airport: NONE, Dry Lake

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 35; private; airplane ratings: single-engine land; medical: class 3, expired; seat: front; toxicology performed; flight hours: 200 total, 113 in this make and model

## Weather

- Conditions: Visual (VMC), Day
- Wind: 50° at 5 knots
- Visibility: 50 statute miles
- Lowest ceiling: none

## FAA reports on this event (1)

The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs).

- [Accident 19911005044919A](https://openairdocs.org/incident/19911005044919A), Oct 5, 1991: Amtr MONGOOSE A, Boulder City, NV, Destroyed, 2 fatal. Unrated private pilot crashed experimental gyrocopter attempting takeoff from dry lake bed.

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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