LAX91LA359 · Benson/Ambrocini/Wentzel B-8MJ
Benson/Ambrocini/Wentzel B-8MJ · Accident: loss of control in flight during initial climb
Event
- NTSB case
- LAX91LA359
- Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
- Accident
- InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
- Completed
- API-reported fatalities
- 1 · all aircraft and ground
- Ground fatalities
- 0
- OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
- General aviation
- WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
- Visual Meteorological Cond
Benson/Ambrocini/Wentzel B-8MJ
- Aircraft type
- Benson/ambrocini/wentzel B-8
- Category
- Gyroplane
- RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
- N8241
- Operator
- Wentzel, Alfred S. · private individual
- Onboard fatalities
- Unknown
- Route
- From not recordedTo not recorded
- Aircraft age
- Not recorded
- Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
- Part 91: General Aviation
- Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
- Initial climb
- First occurrenceThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
- Loss of control in flight
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Substantial
Cause areas
- Pilot in command › Aircraft control, not maintained
- Pilot in command › Flight controls, improper use of
- Pilot in command › Rotation, excessive
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
THE NON HELICOPTER RATED PILOT WAS USING AN UNAPPROVED TAKEOFF AND LANDING AREA BETWEEN HANGERS ON THE AIRPORT. NUMEROUS MAINTENANCE AND CERTIFICATION IRREGULARITIES WERE FOUND. THE GYROCOPTER HAD NOT HAD AN ANNUALLY REQUIRED CONDITION INSPECTION SINCE 1986. NUMEROUS GROUND WITNESSES REPORTED THAT AFTER THE PILOT COMPLETED THE MODIFICATIONS, HE MADE ONE ABORTED ATTEMPT TO TAKEOFF. THE PILOT WAS NEXT SEEN TO TAXI THE GYROCOPTER BACK TO HIS HANGAR WHERE HE MADE SOME MINOR ADJUSTMENTS TO THE ROTOR SYSTEM. THE PILOT THEN TAXIED THE AIRCRAFT BACK TO THE ORIGINAL TAKEOFF SPOT, SPUN UP THE ROTOR SYSTEM AND INITIATED ANOTHER TAKEOFF. THE WITNESSES SAW THE MACHINE LIFT OFF IN A STEEPER THAN NORMAL NOSE HIGH ATTITUDE, THEN THE ROTOR BLADES BEGAN TO WAVE ERRATICALLY 'LIKE SPAGHETTI.' THE GYROCOPTER HIT THE GROUND ON ITS WHEELS AND ROLLED INTO A PICKUP TRUCK. THE GYROCOPTER WAS EXAMINED BY AN FAA AIRWORTHINESS INSPECTOR FAMILIAR WITH THE MACHINES. HE REPORTED THAT HE FOUND NO IDENTIFIABLE PREIMPACT MALFUNCTIONS OR FAILURES.
Probable cause
THE PILOT'S OVER ROTATION OF THE GYROCOPTER DURING THE TAKEOFF SEQUENCE WHICH RESULTED IN A LOSS OF CONTROL. CONTRIBUTING TO THE ACCIDENT WAS THE POOR MAINTENANCE PRACTICES PERFORMED ON THE MACHINE.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record LAX91LA359
- Event ID
- 20001212X17901
- Case number
- LAX91LA359
- Dataset
- historical-pre2008
- Source SHA-256
- 89e2df6d848e7ab3b42e7d7c7a03ff403303057a26ca04c95b3ea67201c3ce74
Source notes (4)
- Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
- Filled from the NTSB case API where the bulk record had no value: investigation status. Values present in the bulk record are kept.
- The date is the local date, which is the same as the UTC date the NTSB stores.
- API snapshot SHA-256: 4dcc31751aeafc098d6a7e2585d32e77c9cc0a5f640e3b75fa8ee6a1155976b1; retrieved 2026-09-21T01:37:51.808Z.