Aircraft Accident/Incident Report

Shafter, California 93263
Friday, January 22, 2010 9:09 PST

NTSB Narrative Summary Released at Completion of Accident

The pilot reported that he was maneuvering the helicopter to make an aerial application pass. At approximately 80 feet above ground level, he heard a muffled "crack/bang" and the helicopter immediately yawed and he experienced lateral vibrations in the cyclic. The pilot then initiated a forced landing with the shaking becoming more violent. The helicopter subsequently landed hard with the engine still running. The main rotor blades contacted and severed the tail boom, and the engine separated from its mounts. Postaccident examination of the helicopter revealed that a main rotor counterweight was missing. Examination of the broken counterweight rod end showed evidence of corrosion over approximately 45 percent of the diameter of the rod end. Maintenance records indicate that a Service Bulletin to inspect main rotor counterweight rods for pit corrosion had not been complied with. The Service Bulletin states that after an initial inspection of the main rotor counterweight rods, recurrent inspections should be accomplished every 300 hours of time in service.

NTSB Probable Cause Narrative

The loss of a main rotor blade counterweight due to corrosion. Contributing to the accident was the failure of the operator to perform the initial and recurrent inspections required by a Service Bulletin to detect the corrosion in the counterweight.

Event Information

Type of Event Accident
Event Date 1/22/2010
Event Day of the Week Friday
Time of Event 909
Event Time Zone Pacific Standard Time
Event City Shafter
Event State CALIFORNIA
Event Country --
Zipcode of the event site 93263
Event Date Year 2010
Event Date Month 1
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude 352824N
Event Location Longitude 1191434W
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 --
Investigator's weather source Weather Observation Facility
Time of the weather observation 854 Pacific Standard Time
Direction of event from weather observation facility (degrees) 105
Weather Observation Facility ID BFL
Elevation of weather observation facility 424
Distance of event from weather observation facility (units?) 10
Time Zone of the weather observation PST
Lighting Conditions Day
Lowest Ceiling Height 4400
Lowest Non-Ceiling Height 3500
Sky/Lowest/Cloud Conditions Few
Sky Condition for Lowest Ceiling Broken
Visibility Runway Visual Range (Feet) --
Visibility Runway Visual Value (Statute Miles) --
Visibility (Statute Miles) 10
Air Temperature at event time (in degrees celsius) 8
Dew Point at event time (in degress fahrenheit) 4
Wind Direction (degrees magnetic) 90
Variable Wind Indicator Wind direction could be determined
Wind Speed (knots) 7
Wind Velocity Indicator --
Wind Gust Indicator Not Gusting
Wind Gust (knots) --
Altimeter Setting at event time (in. Hg) 29.46
Density Altitude (feet) --
Intensity of Precipitation --
METAR weather report --
Event Highest Injury Minor
On Ground, Fatal Injuries --
On Ground, Minor Injuries --
On Ground, Serious Injuries --
Injury Total Fatal --
Injury Total Minor 1
Injury Total None --
Injury Total Serious --
Injury Total All 1
Investigating Agency NTSB
NTSB Docket Number (internal use) 27522
NTSB Notification Source FAA Operations Center
NTSB Notification Date --
NTSB Notification Time --
Fiche Number and/or location -used to find docket information --
Date of most recent change to record Oct 1 2010 4:29PM
User who most recently changed record coos
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N28938
NTSB Number WPR10LA117
Missing Aircraft Indicator --
Federal Aviation Reg. Part Part 137: Agricultural
Type of Flight Plan filed None
Flight plan Was Activated? --
Damage Substantial
Aircraft Fire None
Aircraft Explosion None
Aircraft Manufacturer's Full Name BELL
Aircraft Model 47G-4A
Aircraft Series Identifier --
Aircraft Serial Number 7728
Certified Max Gross Weight --
Aircraft Category Helicopter
Aircraft Registration Class --
Aircraft is a homebuilt? No
Flight Crew Seats --
Cabin Crew Seats --
Passenger Seats --
Total number of seats on the aircraft 3
Number of Engines 1
Fixed gear or retractable gear Fixed
Aircraft, Type of Last Inspection Continuous Airworthiness
Date of Last Inspection --
Airframe hours since last inspection --
Airframe Hours 7207
ELT Installed No
ELT Activated No
ELT Aided Location of Event Site No
ELT Type --
Aircraft Owner Name INLAND CROP DUSTERS INC
Aircraft Owner Street Address 5001 STEARMAN AVE
Aircraft Owner City SHAFTER
Aircraft Owner State CA
Aircraft Owner Country USA
Aircraft Owner Zipcode 93263-4030
Operator is an individual? No
Operator Name INLAND CROP DUSTERS INC
Operator Same as Owner? Yes
Operator Is Doing Business As --
Operator Address Same as Owner? Yes
Operator Street Address 5001 STEARMAN AVE
Operator City SHAFTER
Operator State CA
Operator Country USA
Operator Zip code 93263-4030
Operator Code --
Owner has at least one certificate None
Other Operator of large aircraft? No
Certified for Part 133 or 137 Operation Agriculture
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) Aerial Application
Second Pilot on Board No
Departure Point Same as Event No
Departure Airport Code MIT
Departure City Shafter
Departure State CA
Departure Country USA
Departure Time 850
Departure Time Zone PST
Destination Same as Local Flt dest & departure same, accident can occur anywhere
Destination Airport Code MIT
Destination City Shafter
Destination State CA
Destination Country USA
Specific Phase of Flight --
Report sent to ICAO? --
Evacuation occurred --
Date of most recent change to record Oct 1 2010 4:29PM
User who most recently changed record coos
Since inspection or accident --
Event Location Runway Number and Location N/A
Runway Length --
Runway Width --
Sight Seeing flight No
Air Medical Flight No
Medical Flight --