Aircraft Accident/Incident Report

Moorpark, California 93030
Sunday, October 4, 1998 15:15 PDT

NTSB Narrative Summary Released at Completion of Accident

The helicopter did not return from an afternoon local area flight and the wreckage was located early the following morning. Both main rotor blades, the tail rotor assembly, the tail boom, and a section of the tail rotor drive shaft were found in a debris field approximately 1/8 mile from the fuselage wreckage. Both main rotor blades separated from the hub outboard of the root doubler and exhibited leading edge damage near the tip and downward bending. Additionally, the 'A' blade was bent smoothly aft approximately 30 degrees over its span. The tail boom was separated from the fuselage approximately 2 feet forward of the tail rotor gearbox. The separation exhibited a diagonal slicing appearance from upper forward to lower aft on the boom. The tail rotor drive shaft was separated at the same fuselage station as the tail boom, and the shaft had a dented appearance which resembled the leading edge radius of the main rotor blade. The main rotor mast exhibited a mast-bumping dent on one side of the mast at the hub attachment but no similar dent on the opposite side. Examination of the aircraft did not reveal any mechanical malfunction of the engine or flight control system.

NTSB Probable Cause Narrative

The improper use of the cyclic flight control by the pilot, which resulted in low g flight load condition, which resulted in rotor disk divergence (mast bumping), and the main rotor blade striking and severing the tail boom.

Event Information

Type of Event Accident
Event Date 10/4/1998
Event Day of the Week Sunday
Time of Event 1515
Event Time Zone Pacific Daylight Time
Event City MOORPARK
Event State CALIFORNIA
Event Country --
Zipcode of the event site 93030
Event Date Year 1998
Event Date Month 10
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude
Event Location Longitude
Event Location Airport
Event Location Nearest Airport ID
Indicates whether the acc/inc occurred off or on an airport Off Airport/Airstrip
Distance from airport in statute miles --
Degrees magnetic from airport --
Airport Elevation --
Weather Briefing Completeness Not pertinent
Investigator's weather source Weather Observation Facility
Time of the weather observation 1551 Pacific Daylight Time
Direction of event from weather observation facility (degrees) 240
Weather Observation Facility ID OXR
Elevation of weather observation facility 43
Distance of event from weather observation facility (units?) 20
Time Zone of the weather observation PDT
Lighting Conditions Day
Lowest Ceiling Height 0
Lowest Non-Ceiling Height 0
Sky/Lowest/Cloud Conditions Clear
Sky Condition for Lowest Ceiling None
Visibility Runway Visual Range (Feet) 0
Visibility Runway Visual Value (Statute Miles) 0
Visibility (Statute Miles) 10
Air Temperature at event time (in degrees celsius) 16
Dew Point at event time (in degress fahrenheit) 7
Wind Direction (degrees magnetic) 30
Variable Wind Indicator Unknown
Wind Speed (knots) 6
Wind Velocity Indicator Unknown
Wind Gust Indicator Not Gusting
Wind Gust (knots) 0
Altimeter Setting at event time (in. Hg) 29
Density Altitude (feet) --
Intensity of Precipitation Unknown
METAR weather report --
Event Highest Injury Fatal
On Ground, Fatal Injuries 0
On Ground, Minor Injuries 0
On Ground, Serious Injuries 0
Injury Total Fatal 1
Injury Total Minor --
Injury Total None --
Injury Total Serious --
Injury Total All 1
Investigating Agency NTSB
NTSB Docket Number (internal use) 1924
NTSB Notification Source --
NTSB Notification Date Oct 5 1998 12:00AM
NTSB Notification Time 523
Fiche Number and/or location -used to find docket information IMAGE
Date of most recent change to record Dec 11 2000 11:50AM
User who most recently changed record dbo
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N418MB
NTSB Number LAX99LA004
Missing Aircraft Indicator N
Federal Aviation Reg. Part Part 91: General Aviation
Type of Flight Plan filed None
Flight plan Was Activated? --
Damage Destroyed
Aircraft Fire None
Aircraft Explosion None
Aircraft Manufacturer's Full Name Burson
Aircraft Model REVOLUTION MINI 500
Aircraft Series Identifier REVOLUTION
Aircraft Serial Number 0279
Certified Max Gross Weight 840
Aircraft Category Helicopter
Aircraft Registration Class U.S. Registered/U.S. Soil
Aircraft is a homebuilt? Yes
Flight Crew Seats --
Cabin Crew Seats --
Passenger Seats --
Total number of seats on the aircraft 1
Number of Engines 1
Fixed gear or retractable gear Fixed
Aircraft, Type of Last Inspection Annual
Date of Last Inspection Apr 18 1998 12:00AM
Airframe hours since last inspection 33
Airframe Hours 33
ELT Installed Yes
ELT Activated No
ELT Aided Location of Event Site Unknown
ELT Type --
Aircraft Owner Name WILLIAM MARK BURSON
Aircraft Owner Street Address 3276 TEXAS AVENUE
Aircraft Owner City SIMI VALLEY
Aircraft Owner State CA
Aircraft Owner Country
Aircraft Owner Zipcode 93063
Operator is an individual? --
Operator Name
Operator Same as Owner? Yes
Operator Is Doing Business As --
Operator Address Same as Owner? Yes
Operator Street Address
Operator City
Operator State
Operator Country
Operator Zip code
Operator Code
Owner has at least one certificate None
Other Operator of large aircraft? No
Certified for Part 133 or 137 Operation Unknown
Operator Certificate Number --
Indicates whether an air carrier operation was scheduled or not --
Indicates Domestic or International Flight --
Operator carrying Pax/Cargo/Mail --
Type of Flying (Per_Bus / Primary) Personal
Second Pilot on Board No
Departure Point Same as Event Yes
Departure Airport Code
Departure City
Departure State
Departure Country
Departure Time 1430
Departure Time Zone PDT
Destination Same as Local Flt dest & departure same, accident can occur anywhere
Destination Airport Code
Destination City
Destination State
Destination Country
Specific Phase of Flight Maneuvering
Report sent to ICAO? --
Evacuation occurred --
Date of most recent change to record Jan 2 2001 10:34AM
User who most recently changed record dbo
Since inspection or accident --
Event Location Runway Number and Location 0
Runway Length --
Runway Width --
Sight Seeing flight No
Air Medical Flight No
Medical Flight --