N/A Airport
Aircraft Accident/Incident Report

Philip, South Dakota 57567
Saturday, October 1, 2011 12:55 MDT

NTSB Narrative Summary Released at Completion of Accident

The helicopter was on a cross-country flight when it experienced a separation of the main rotor mast 8 inches below the teeter bolt, and the main rotor blade assembly separated from the flying helicopter. Subsequently, the helicopter impacted terrain and a postimpact fire ensued. Examination of the mast revealed fracture features consistent with overload failure and mechanical damage indicative of mast bumping. An examination of the airframe, engine, and remaining systems revealed no preimpact anomalies. The reason for the mast bumping event could not be determined due to the amount of thermal damage to the wreckage.

NTSB Probable Cause Narrative

The in-flight separation of the main rotor mast following a mast bumping event. The reason for the mast bumping event could not be determined due to postaccident damage.

Event Information

Type of Event Accident
Event Date 10/1/2011
Event Day of the Week Saturday
Time of Event 1255
Event Time Zone Mountain Daylight Time
Event City Philip
Event State SOUTH DAKOTA
Event Country --
Zipcode of the event site 57567
Event Date Year 2011
Event Date Month 10
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude 440104N
Event Location Longitude 1013804W
Event Location Airport N/A
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 1255 Mountain Daylight Time
Direction of event from weather observation facility (degrees) 40
Weather Observation Facility ID PHP
Elevation of weather observation facility 2209
Distance of event from weather observation facility (units?) 3
Time Zone of the weather observation MDT
Lighting Conditions Day
Lowest Ceiling Height --
Lowest Non-Ceiling Height --
Sky/Lowest/Cloud Conditions Clear
Sky Condition for Lowest Ceiling None
Visibility Runway Visual Range (Feet) --
Visibility Runway Visual Value (Statute Miles) --
Visibility (Statute Miles) 10
Air Temperature at event time (in degrees celsius) 29
Dew Point at event time (in degress fahrenheit) 4
Wind Direction (degrees magnetic) 150
Variable Wind Indicator Wind direction could be determined
Wind Speed (knots) 6
Wind Velocity Indicator --
Wind Gust Indicator Not Gusting
Wind Gust (knots) --
Altimeter Setting at event time (in. Hg) 30
Density Altitude (feet) --
Intensity of Precipitation --
METAR weather report METAR KPHP 011855Z AUTO 15006KT 10SM CLR 29/04 A30
Event Highest Injury Fatal
On Ground, Fatal Injuries --
On Ground, Minor Injuries --
On Ground, Serious Injuries --
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) 32488
NTSB Notification Source FAA
NTSB Notification Date --
NTSB Notification Time --
Fiche Number and/or location -used to find docket information --
Date of most recent change to record Feb 28 2014 4:12PM
User who most recently changed record lebt
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N266CY
NTSB Number CEN12FA001
Missing Aircraft Indicator --
Federal Aviation Reg. Part Part 91: General Aviation
Type of Flight Plan filed None
Flight plan Was Activated? --
Damage Destroyed
Aircraft Fire Ground
Aircraft Explosion None
Aircraft Manufacturer's Full Name ROBINSON HELICOPTER CO
Aircraft Model R66
Aircraft Series Identifier --
Aircraft Serial Number 0010
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 5
Number of Engines 1
Fixed gear or retractable gear Fixed
Aircraft, Type of Last Inspection 100 Hour
Date of Last Inspection Jun 6 2011 12:00AM
Airframe hours since last inspection 83
Airframe Hours 120
ELT Installed Yes
ELT Activated No
ELT Aided Location of Event Site Unknown
ELT Type Unknown
Aircraft Owner Name P P & J LLC
Aircraft Owner Street Address PO BOX 908
Aircraft Owner City GILLETTE
Aircraft Owner State WY
Aircraft Owner Country USA
Aircraft Owner Zipcode 82717-0908
Operator is an individual? No
Operator Name P P & J LLC
Operator Same as Owner? Yes
Operator Is Doing Business As --
Operator Address Same as Owner? Yes
Operator Street Address PO BOX 908
Operator City GILLETTE
Operator State WY
Operator Country USA
Operator Zip code 82717-0908
Operator Code --
Owner has at least one certificate None
Other Operator of large aircraft? --
Certified for Part 133 or 137 Operation --
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 No
Departure Airport Code GCC
Departure City Gillette
Departure State WY
Departure Country USA
Departure Time 1105
Departure Time Zone MDT
Destination Same as Local Flt --
Destination Airport Code ICR
Destination City Winner
Destination State SD
Destination Country USA
Specific Phase of Flight --
Report sent to ICAO? --
Evacuation occurred --
Date of most recent change to record Feb 28 2014 4:22PM
User who most recently changed record lebt
Since inspection or accident Time of Accident
Event Location Runway Number and Location N/A
Runway Length --
Runway Width --
Sight Seeing flight No
Air Medical Flight No
Medical Flight --