Aircraft Accident/Incident Report

Walnut Creek, California 94598
Monday, February 21, 1994 10:15 PST

NTSB Narrative Summary Released at Completion of Accident

THE HELICOPTER WAS OBSERVED FLYING LOW IN A GRADUAL DESCENT OVER A RESIDENTIAL AREA HEADING TOWARD AN OPEN FIELD. WITNESSES SAID THE HELICOPTER NOISE LEVEL WAS QUIET, BUT NOT SOUNDLESS. AT 200 FEET ABOVE THE GROUND, THE HELICOPTER ROLLED LEFT TO AN INVERTED FLIGHT ATTITUDE AND THEN DESCENDED IN A NOSE-DOWN ATTITUDE. WRECKAGE EXAMINATION DID NOT FIND ANY PREIMPACT MECHANICAL FAILURES WITH THE HELICOPTER'S FLIGHT CONTROL OR DRIVE SYSTEMS. SIGNATURES ON THE INTERNAL ROTATING COMPONENTS OF BOTH ENGINES, THE DRIVE SYSTEM, MAIN ROTOR BLADES, AND TAIL ROTOR BLADES WERE INDICATIVE OF LOW RPM. EXAMINATION OF THE ENGINE FUEL SYSTEM REVEALED EVIDENCE OF FOREIGN PARTICLES IN THE FLOW DIVIDER AND FUEL NOZZLES. POSTACCIDENT FUEL SAMPLES FROM THE REFUELING TRUCK WERE TESTED IN A LABORATORY. ACCORDING TO THE LAB REPORT, THE FUEL HAD A TENDENCY TO ABSORB AND RETAIN WATER, AND A PRESENCE OF MICROBIAL CONTAMINATION WAS NOTED. IN ADDITION TO THE LAB TESTS, FUEL SAMPLES FROM THE OPERATORS REFUELING TRUCKS WERE INDEPENDENTLY TESTED WITH WATER DETECTION PASTE AND TESTED POSITIVE FOR WATER.

NTSB Probable Cause Narrative

Inadequate fuel quality control procedures by the helicopter operator resulting in fuel contamination and a loss of engine power. The pilot's decision to extend the autorotative glide to avoid striking residential homes, which resulted in low main rotor rpm and a subsequent in-flight loss of control, is also causal in this accident. A factor in the accident was the unsuitable nature of the residential area over which the loss of power occurred for a successful forced landing.

Event Information

Type of Event Accident
Event Date 2/21/1994
Event Day of the Week Monday
Time of Event 1015
Event Time Zone Pacific Standard Time
Event City WALNUT CREEK
Event State CALIFORNIA
Event Country --
Zipcode of the event site 94598
Event Date Year 1994
Event Date Month 2
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 Unknown
Investigator's weather source Weather Observation Facility
Time of the weather observation 1020 Pacific Standard Time
Direction of event from weather observation facility (degrees) 180
Weather Observation Facility ID CCR
Elevation of weather observation facility 23
Distance of event from weather observation facility (units?) 6
Time Zone of the weather observation PST
Lighting Conditions Day
Lowest Ceiling Height 5000
Lowest Non-Ceiling Height 2500
Sky/Lowest/Cloud Conditions Scattered
Sky Condition for Lowest Ceiling Broken
Visibility Runway Visual Range (Feet) 0
Visibility Runway Visual Value (Statute Miles) 0
Visibility (Statute Miles) 20
Air Temperature at event time (in degrees celsius) 11
Dew Point at event time (in degress fahrenheit) 8
Wind Direction (degrees magnetic) 200
Variable Wind Indicator Unknown
Wind Speed (knots) 11
Wind Velocity Indicator Unknown
Wind Gust Indicator Not Gusting
Wind Gust (knots) 0
Altimeter Setting at event time (in. Hg) 30
Density Altitude (feet) --
Intensity of Precipitation Light
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 3
Injury Total Minor --
Injury Total None --
Injury Total Serious --
Injury Total All 3
Investigating Agency NTSB
NTSB Docket Number (internal use) 1548
NTSB Notification Source --
NTSB Notification Date Feb 21 1994 12:00AM
NTSB Notification Time 1050
Fiche Number and/or location -used to find docket information IMAGE
Date of most recent change to record Dec 6 2000 10:40AM
User who most recently changed record dbo
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N581BG
NTSB Number LAX94FA130
Missing Aircraft Indicator N
Federal Aviation Reg. Part Part 91: General Aviation
Type of Flight Plan filed Company VFR
Flight plan Was Activated? --
Damage Destroyed
Aircraft Fire Ground
Aircraft Explosion None
Aircraft Manufacturer's Full Name SIKORSKY
Aircraft Model S-58T
Aircraft Series Identifier S-58T
Aircraft Serial Number 58-1487
Certified Max Gross Weight 12500
Aircraft Category Helicopter
Aircraft Registration Class U.S. Registered/U.S. Soil
Aircraft is a homebuilt? No
Flight Crew Seats --
Cabin Crew Seats --
Passenger Seats --
Total number of seats on the aircraft 11
Number of Engines 2
Fixed gear or retractable gear Fixed
Aircraft, Type of Last Inspection AAIP
Date of Last Inspection --
Airframe hours since last inspection 15
Airframe Hours 12735
ELT Installed Yes
ELT Activated Unknown
ELT Aided Location of Event Site Unknown
ELT Type --
Aircraft Owner Name AIR ONE, INC
Aircraft Owner Street Address 1144 COLEMAN AVE
Aircraft Owner City SAN JOSE
Aircraft Owner State CA
Aircraft Owner Country
Aircraft Owner Zipcode 95110
Operator is an individual? --
Operator Name AIR ONE, INC
Operator Same as Owner? Yes
Operator Is Doing Business As --
Operator Address Same as Owner? Yes
Operator Street Address 1144 COLEMAN AVE
Operator City SAN JOSE
Operator State CA
Operator Country
Operator Zip code 95110
Operator Code ONRG
Owner has at least one certificate Yes - certificate holder
Other Operator of large aircraft? No
Certified for Part 133 or 137 Operation External Load
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) Unknown
Second Pilot on Board No
Departure Point Same as Event No
Departure Airport Code
Departure City CONCORD
Departure State CA
Departure Country
Departure Time 1010
Departure Time Zone PST
Destination Same as Local Flt --
Destination Airport Code SJC
Destination City SAN JOSE
Destination State CA
Destination Country
Specific Phase of Flight Cruise
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 --