Individually Owned: 150,657
Corporate Owned: 137,281
Aircraft Accident/Incident Report
Haena, Hawaii 96713
Sunday, March 11, 2007 12:59 HST
NTSB Narrative Summary Released at Completion of Accident
The helicopter pilot reported that he was conducting a Part 135 air tour flight with 4 passengers on board the helicopter. The helicopter was about 1,500 feet above ground level with about 80 - 85 knots of airspeed when within a split-second he heard two loud "bangs." The nose of the helicopter pitched down and the helicopter yawed to the right. He applied left pedal but without effect. He attempted to "get more forward airspeed," but each time he did the helicopter nosed over and yawed to the right. The right yaw developed into a tight spin, and he realized that he "lost his tail rotor." The pilot executed an autorotation to a clearing located at a campground. The helicopter impacted the trees at the western edge of the clearing during the autorotation. The helicopter impacted the terrain on its right, front side. Inspection of the helicopter revealed that the tail rotor output shaft and the tail rotor blades separated from the tail rotor gearbox. The tail rotor assembly was inspected at the National Transportation Safety Board's Materials Laboratory. The inspection revealed that the tail rotor blade assembly fractured through the root fitting in the general area that coincided with a hole for the blade retention bolt. The root fitting contained a 1-inch nominal diameter longitudinal hub bore with a tapered (conical) hole bottom. A relief radius was located between the hub bore and the conical hole bottom. The inspection revealed crack arrest marks typical of a fatigue cracking that emanated from multiple origins at the relief radius between the hub bore and conical hole bottom. The relief radius measured approximately 0.001 inch, much less than specified by the engineering drawing (0.12 inch and 0.15 inch). On April 26, 2007, McDonnell Helicopters, Inc. (MDHI) issued mandatory Service Bulletin (SB) 369D-204, 369E-099, 369F-084, 369H-247, titled "Tail Rotor Blade Assembly, One Time Inspection." According to MDHI SB, before further flight, the tail rotor should be removed from helicopter models 369 (Army YOH-6A), 369 (Army OH-6A), 369H, 369HM, 369HS, 369HE, 369D, 369E, 369F, and 369FF. The hub bore should be visually examined with a flashlight. If the relief radius does not contain a smooth transition between the bore and conical bottom hole, the root fitting should be removed from service. On April 27, 2007, the Federal Aviation Administration issued emergency Airworthiness Directive (AD) 2007-09-51 that mandated inspection of the root fittings per the MDHI SB.
NTSB Probable Cause Narrative
The fatigue failure of the tail rotor blade root fitting due to a manufacturing defect which resulted in the separation of the tail rotor system and loss of tail rotor control. A contributing factor to the accident were the trees that the helicopter struck during the autorotation.
Event Information
| Type of Event | Accident |
| Event Date | 3/11/2007 |
| Event Day of the Week | Sunday |
| Time of Event | 1259 |
| Event Time Zone | Hawaii Standard Time |
| Event City | Haena |
| Event State | HAWAII |
| Event Country | -- |
| Zipcode of the event site | 96713 |
| Event Date Year | 2007 |
| Event Date Month | 3 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | 221314N |
| Event Location Longitude | 1593312W |
| 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 | 1153 Hawaii Standard Time |
| Direction of event from weather observation facility (degrees) | 130 |
| Weather Observation Facility ID | PHLI |
| Elevation of weather observation facility | 153 |
| Distance of event from weather observation facility (units?) | 17 |
| Time Zone of the weather observation | HST |
| Lighting Conditions | Day |
| Lowest Ceiling Height | 3700 |
| Lowest Non-Ceiling Height | 2800 |
| Sky/Lowest/Cloud Conditions | Scattered |
| Sky Condition for Lowest Ceiling | Overcast |
| Visibility Runway Visual Range (Feet) | -- |
| Visibility Runway Visual Value (Statute Miles) | -- |
| Visibility (Statute Miles) | 8 |
| Air Temperature at event time (in degrees celsius) | 23 |
| Dew Point at event time (in degress fahrenheit) | 18 |
| Wind Direction (degrees magnetic) | 10 |
| Variable Wind Indicator | Wind direction could be determined |
| Wind Speed (knots) | 4 |
| Wind Velocity Indicator | -- |
| Wind Gust Indicator | Unknown |
| Wind Gust (knots) | -- |
| Altimeter Setting at event time (in. Hg) | 29.94 |
| Density Altitude (feet) | -- |
| Intensity of Precipitation | -- |
| METAR weather report | METAR PHLI 102353Z 01004KT 8SM -RA SCT028 OVC037 2 |
| 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 | 1 |
| Injury Total Serious | 3 |
| Injury Total All | 4 |
| Investigating Agency | NTSB |
| NTSB Docket Number (internal use) | 23901 |
| NTSB Notification Source | FAA |
| NTSB Notification Date | Mar 11 2007 12:00AM |
| NTSB Notification Time | -- |
| Fiche Number and/or location -used to find docket information | DMS |
| Date of most recent change to record | Jul 30 2008 9:00AM |
| User who most recently changed record | NTSB\johb |
| Basic weather conditions | Visual Meteorological Cond |
| FAA District Office | FAA Honolulu FSDO |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N911VC |
| NTSB Number | CHI07MA083 |
| Missing Aircraft Indicator | -- |
| Federal Aviation Reg. Part | Part 135: Air Taxi & Commuter |
| 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 | McDonnell Douglas |
| Aircraft Model | 369FF |
| Aircraft Series Identifier | -- |
| Aircraft Serial Number | 0049FF |
| Certified Max Gross Weight | 3100 |
| 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 | Feb 1 2007 12:00AM |
| Airframe hours since last inspection | 43 |
| Airframe Hours | 7799 |
| ELT Installed | Yes |
| ELT Activated | No |
| ELT Aided Location of Event Site | No |
| ELT Type | -- |
| Aircraft Owner Name | Smoky Mountain Helicopters, Inc. |
| Aircraft Owner Street Address | 2979 Barley Mill Rd. |
| Aircraft Owner City | Yorklyn |
| Aircraft Owner State | DE |
| Aircraft Owner Country | USA |
| Aircraft Owner Zipcode | 19736 |
| Operator is an individual? | No |
| Operator Name | Inter-Island Helicopter Inc. |
| Operator Same as Owner? | No |
| Operator Is Doing Business As | -- |
| Operator Address Same as Owner? | No |
| Operator Street Address | P.O. Box 156 |
| Operator City | Hanapepe |
| Operator State | HI |
| Operator Country | USA |
| Operator Zip code | 96716 |
| Operator Code | -- |
| Owner has at least one certificate | -- |
| 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 | Non-scheduled |
| Indicates Domestic or International Flight | Domestic |
| Operator carrying Pax/Cargo/Mail | Passenger Only |
| Type of Flying (Per_Bus / Primary) | -- |
| Second Pilot on Board | No |
| Departure Point Same as Event | No |
| Departure Airport Code | PAK |
| Departure City | Hanapepe |
| Departure State | HI |
| Departure Country | USA |
| Departure Time | 1210 |
| Departure Time Zone | HST |
| Destination Same as Local Flt | dest & departure same, accident can occur anywhere |
| Destination Airport Code | -- |
| Destination City | -- |
| Destination State | -- |
| Destination Country | -- |
| Specific Phase of Flight | Cruise |
| Report sent to ICAO? | -- |
| Evacuation occurred | -- |
| Date of most recent change to record | Jul 9 2008 5:35PM |
| User who most recently changed record | BOWL |
| Since inspection or accident | Time of Accident |
| Event Location Runway Number and Location | NA |
| Runway Length | -- |
| Runway Width | -- |
| Sight Seeing flight | Yes |
| Air Medical Flight | No |
| Medical Flight | -- |