Individually Owned: 150,657
Corporate Owned: 137,281
Aircraft Accident/Incident Report
Parlier, California 93648
Wednesday, February 17, 2010 14:50 PST
NTSB Narrative Summary Released at Completion of Accident
The helicopter pilot was on the first leg of a ferry flight. The helicopter was 3.2 hours out of its 2,200-hour overhaul. The pilot reported that he was in straight-and-level flight and he initiated a right turn. The helicopter immediately rolled to the right and entered a low-G condition. The pilot responded appropriately and righted the helicopter. He then conducted a power-on landing. As the main rotor system came to a stop, one of the blades impacted the tailboom. Post landing examination of the rotorhead revealed that the pitch change link on the red main rotor blade had fractured, the spindle tusk had sheared off, and damage to both elastomeric teeter stops was evident. Metallurgical examination of the spindle tusk determined that it failed in a downward direction relative to the rotor blade due to shear overstress. Examination of the pitch change link determined that it failed due to overstress characterized by reverse bending numerous times to failure. Witness marks on the pitch link and pitch change arm indicated that the angle of the blade at the time of the pitch link failure was 45-degrees downward, an angle that could be achieved if the spindle tusk had already been fractured. According to Robinson Helicopter Company, this angle could also be obtained during extreme teeter of the hub/blade during a mast bumping event. A Robinson Helicopter Company publication notes, "Pushing the cyclic forward following a pull-up or rapid climb, or even from level flight, produces a low-G (weightless) flight condition. If the helicopter is still pitching forward when the pilot applies aft cyclic to reload the rotor, the rotor disk may tilt aft relative to the fuselage before it is reloaded. The main rotor torque reaction will then combine with tail rotor thrust to produce a powerful right rolling moment to the fuselage. With no lift from the rotor, there is no lateral control to stop the rapid right roll and mast bumping can occur."
NTSB Probable Cause Narrative
The pilot inadvertently entered a low-G condition during cruise flight, which resulted in a momentary loss of control of the helicopter and mast bumping.
Event Information
| Type of Event | Accident |
| Event Date | 2/17/2010 |
| Event Day of the Week | Wednesday |
| Time of Event | 1450 |
| Event Time Zone | Pacific Standard Time |
| Event City | Parlier |
| Event State | CALIFORNIA |
| Event Country | -- |
| Zipcode of the event site | 93648 |
| Event Date Year | 2010 |
| Event Date Month | 2 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | 373725N |
| Event Location Longitude | 1193025W |
| 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 | 1453 Pacific Standard Time |
| Direction of event from weather observation facility (degrees) | 300 |
| Weather Observation Facility ID | FAT |
| Elevation of weather observation facility | 336 |
| Distance of event from weather observation facility (units?) | 15 |
| Time Zone of the weather observation | PST |
| Lighting Conditions | Day |
| Lowest Ceiling Height | -- |
| Lowest Non-Ceiling Height | -- |
| Sky/Lowest/Cloud Conditions | Few |
| Sky Condition for Lowest Ceiling | None |
| Visibility Runway Visual Range (Feet) | -- |
| Visibility Runway Visual Value (Statute Miles) | -- |
| Visibility (Statute Miles) | 5 |
| Air Temperature at event time (in degrees celsius) | 21 |
| Dew Point at event time (in degress fahrenheit) | 11 |
| Wind Direction (degrees magnetic) | -- |
| Variable Wind Indicator | -- |
| Wind Speed (knots) | -- |
| Wind Velocity Indicator | Calm |
| Wind Gust Indicator | -- |
| Wind Gust (knots) | -- |
| Altimeter Setting at event time (in. Hg) | 29.95 |
| Density Altitude (feet) | -- |
| Intensity of Precipitation | -- |
| METAR weather report | -- |
| Event Highest Injury | None |
| On Ground, Fatal Injuries | -- |
| On Ground, Minor Injuries | -- |
| On Ground, Serious Injuries | -- |
| Injury Total Fatal | -- |
| Injury Total Minor | -- |
| Injury Total None | 2 |
| Injury Total Serious | -- |
| Injury Total All | -- |
| Investigating Agency | NTSB |
| NTSB Docket Number (internal use) | 27069 |
| NTSB Notification Source | FAA Com Center |
| NTSB Notification Date | -- |
| NTSB Notification Time | -- |
| Fiche Number and/or location -used to find docket information | -- |
| Date of most recent change to record | Jun 17 2010 1:01PM |
| User who most recently changed record | stam |
| Basic weather conditions | Visual Meteorological Cond |
| FAA District Office | -- |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N313DA |
| NTSB Number | WPR10LA138 |
| Missing Aircraft Indicator | -- |
| Federal Aviation Reg. Part | Part 91: General Aviation |
| Type of Flight Plan filed | None |
| Flight plan Was Activated? | No |
| Damage | Substantial |
| Aircraft Fire | None |
| Aircraft Explosion | None |
| Aircraft Manufacturer's Full Name | ROBINSON HELICOPTER |
| Aircraft Model | R22 BETA |
| Aircraft Series Identifier | -- |
| Aircraft Serial Number | 3860 |
| Certified Max Gross Weight | 1370 |
| 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 | 2 |
| Number of Engines | 1 |
| Fixed gear or retractable gear | Fixed |
| Aircraft, Type of Last Inspection | Annual |
| Date of Last Inspection | Feb 1 2010 12:00AM |
| Airframe hours since last inspection | 3 |
| Airframe Hours | 3 |
| ELT Installed | Yes |
| ELT Activated | No |
| ELT Aided Location of Event Site | No |
| ELT Type | C91 |
| Aircraft Owner Name | HELIMARK LLC |
| Aircraft Owner Street Address | 771 S CARSON ST STE 4 |
| Aircraft Owner City | CARSON CITY |
| Aircraft Owner State | NV |
| Aircraft Owner Country | USA |
| Aircraft Owner Zipcode | 89701 |
| Operator is an individual? | No |
| Operator Name | Richard Coe |
| Operator Same as Owner? | No |
| Operator Is Doing Business As | -- |
| Operator Address Same as Owner? | No |
| Operator Street Address | -- |
| Operator City | Las Vegas |
| Operator State | NV |
| Operator Country | USA |
| 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 | -- |
| 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 | FAT |
| Departure City | Fresno |
| Departure State | CA |
| Departure Country | USA |
| Departure Time | 1430 |
| Departure Time Zone | PST |
| Destination Same as Local Flt | -- |
| Destination Airport Code | BFL |
| Destination City | Bakersfield |
| Destination State | CA |
| Destination Country | USA |
| Specific Phase of Flight | -- |
| Report sent to ICAO? | -- |
| Evacuation occurred | -- |
| Date of most recent change to record | Jun 17 2010 12:13PM |
| User who most recently changed record | stam |
| Since inspection or accident | Last Inspection |
| Event Location Runway Number and Location | N/A |
| Runway Length | -- |
| Runway Width | -- |
| Sight Seeing flight | No |
| Air Medical Flight | No |
| Medical Flight | -- |