Individually Owned: 150,657
Corporate Owned: 137,281
N/A Airport
Aircraft Accident/Incident Report
Tehachapi, California 93561
Sunday, September 4, 2011 15:00 PDT
NTSB Narrative Summary Released at Completion of Accident
During an external load operation to drop water on a fire, the helicopter was about 100 feet above ground level at 10 knots when the engine rpm light illuminated and the low rotor rpm horn sounded. The emergency procedures section of the flight manual states that in the event of an engine failure or low rpm, a red light will illuminate and an audio signal will sound when the audio switch is in the AUDIO position. The flight manual instructs the pilot to immediately execute an autorotative descent. The pilot released the water, and made a left-pedal turn to exit the canyon and move away from the fire. He checked his engine rotor rpm gauge and saw that the needles had split: the rotor needle was at the 4-5 o'clock position, and the engine needle was at the 6-o'clock position, which he stated indicated maximum rpm. He maneuvered to establish an autorotation into a landing zone. The helicopter sustained substantial damage to the airframe and tail boom as the result of a hard landing, which collapsed the landing skid.
Postaccident examination discovered that the N2 tachometer drive shaft was sheered as a result of torsional overstress. The N2 tachometer drive delivers engine rpm readings to the cockpit engine tachometer; failure of the N2 tachometer drive would send erroneous engine rpm readings to the cockpit. Accordingly, the pilot's instruments indicated that there was an engine overspeed, but the warning lights and audio were indicating a low power condition. The pilot elected to perform an autorotative landing in accordance with the flight manual instructions for a low rotor rpm.
NTSB Probable Cause Narrative
The pilot's inability to adequately execute an emergency autorotation due to the flight's low altitude during external load operations, which resulted in a hard landing. Contributing to the accident was a torsionally overstressed tachometer shaft, which sent erroneous engine rpm readings to the cockpit.
Event Information
| Type of Event | Accident |
| Event Date | 9/4/2011 |
| Event Day of the Week | Sunday |
| Time of Event | 1500 |
| Event Time Zone | Pacific Daylight Time |
| Event City | Tehachapi |
| Event State | CALIFORNIA |
| Event Country | -- |
| Zipcode of the event site | 93561 |
| Event Date Year | 2011 |
| Event Date Month | 9 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | 350352N |
| Event Location Longitude | 1182525W |
| 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 | 1455 Pacific Daylight Time |
| Direction of event from weather observation facility (degrees) | -- |
| Weather Observation Facility ID | KTSP |
| Elevation of weather observation facility | 4001 |
| Distance of event from weather observation facility (units?) | -- |
| Time Zone of the weather observation | PDT |
| 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) | 30 |
| Dew Point at event time (in degress fahrenheit) | -2 |
| Wind Direction (degrees magnetic) | 310 |
| Variable Wind Indicator | Wind direction could be determined |
| Wind Speed (knots) | 13 |
| Wind Velocity Indicator | -- |
| Wind Gust Indicator | Gusting |
| Wind Gust (knots) | 19 |
| Altimeter Setting at event time (in. Hg) | 30.03 |
| 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) | 33156 |
| 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 | Aug 21 2014 3:55PM |
| User who most recently changed record | plah |
| Basic weather conditions | Visual Meteorological Cond |
| FAA District Office | -- |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N205WW |
| NTSB Number | WPR11GA431 |
| Missing Aircraft Indicator | -- |
| Federal Aviation Reg. Part | Part 133: Rotorcraft Ext. Load |
| Type of Flight Plan filed | Company VFR |
| Flight plan Was Activated? | Yes |
| Damage | Substantial |
| Aircraft Fire | None |
| Aircraft Explosion | None |
| Aircraft Manufacturer's Full Name | BELL |
| Aircraft Model | 205 |
| Aircraft Series Identifier | A1 |
| Aircraft Serial Number | 30329 |
| Certified Max Gross Weight | 10500 |
| 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 | 11 |
| Number of Engines | 1 |
| Fixed gear or retractable gear | Fixed |
| Aircraft, Type of Last Inspection | 100 Hour |
| Date of Last Inspection | Aug 31 2011 12:00AM |
| Airframe hours since last inspection | 89 |
| Airframe Hours | 3560 |
| ELT Installed | Yes |
| ELT Activated | No |
| ELT Aided Location of Event Site | Unknown |
| ELT Type | Unknown |
| Aircraft Owner Name | Blades LLC |
| Aircraft Owner Street Address | -- |
| Aircraft Owner City | Renton |
| Aircraft Owner State | WA |
| Aircraft Owner Country | USA |
| Aircraft Owner Zipcode | 98057 |
| Operator is an individual? | No |
| Operator Name | Kern County |
| Operator Same as Owner? | No |
| Operator Is Doing Business As | -- |
| Operator Address Same as Owner? | No |
| Operator Street Address | -- |
| Operator City | Bakersfield |
| Operator State | CA |
| Operator Country | USA |
| Operator Zip code | -- |
| Operator Code | -- |
| Owner has at least one certificate | Yes - certificate holder |
| 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) | -- |
| Second Pilot on Board | No |
| Departure Point Same as Event | Yes |
| Departure Airport Code | -- |
| Departure City | Tehachapi |
| Departure State | CA |
| Departure Country | USA |
| Departure Time | 1355 |
| Departure Time Zone | PDT |
| Destination Same as Local Flt | dest & departure same, accident can occur anywhere |
| Destination Airport Code | -- |
| Destination City | Tehachapi |
| Destination State | CA |
| Destination Country | USA |
| Specific Phase of Flight | -- |
| Report sent to ICAO? | -- |
| Evacuation occurred | -- |
| Date of most recent change to record | Sep 23 2014 7:35PM |
| User who most recently changed record | coos |
| 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 | -- |