Individually Owned: 150,657
Corporate Owned: 137,281
Aircraft Accident/Incident Report
Lost Hills, California 93249
Tuesady, August 24, 1999 23:00 PDT
NTSB Narrative Summary Released at Completion of Accident
During the takeoff initial climb as the helicopter accelerated through 25 to 30 miles per hour, the 90-degree gearbox fractured through the center of the gearbox case and separated from the tailboom. The pilot was able to slow the spin rate and performed a hovering autorotation. A portion of the tail boom impacted a barbed wire fence as the helicopter settled vertically. Metallurgical examination of the gearbox case fractures disclosed overload features. Internal examination of the gearbox and gears showed that the pinion and gear teeth had disengaged. The disengagement lasted a short period of time. As a result of the disengaged gear and pinion rotating against each other, the gearbox case became overloaded and subsequently separated. The wear patterns on the pinion and gear teeth drive side did not meet the patterns specified in the maintenance manual; the patterns extended off the toe ends and the tips of the teeth. The gearbox, which is an 'on-condition' component, was last overhauled or repaired in 1984. There is no requirement for an internal inspection of the tail rotor gearbox during routine or annual maintenance inspections.
NTSB Probable Cause Narrative
Failure and separation of the 90-degree gearbox as a result of the disengagement of the pinion and gear teeth. The cause(s) of the pinion and gear disengagement were undetermined.
Event Information
| Type of Event | Accident |
| Event Date | 8/24/1999 |
| Event Day of the Week | Tuesday |
| Time of Event | 2300 |
| Event Time Zone | Pacific Daylight Time |
| Event City | LOST HILLS |
| Event State | CALIFORNIA |
| Event Country | -- |
| Zipcode of the event site | 93249 |
| Event Date Year | 1999 |
| Event Date Month | 8 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | |
| Event Location Longitude | |
| 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 | Unknown |
| Investigator's weather source | Weather Observation Facility |
| Time of the weather observation | 2256 Pacific Daylight Time |
| Direction of event from weather observation facility (degrees) | 120 |
| Weather Observation Facility ID | BFL |
| Elevation of weather observation facility | 507 |
| Distance of event from weather observation facility (units?) | 34 |
| Time Zone of the weather observation | PDT |
| Lighting Conditions | Night/Bright |
| Lowest Ceiling Height | 0 |
| Lowest Non-Ceiling Height | 0 |
| Sky/Lowest/Cloud Conditions | Clear |
| Sky Condition for Lowest Ceiling | Unknown |
| Visibility Runway Visual Range (Feet) | 0 |
| Visibility Runway Visual Value (Statute Miles) | 0 |
| Visibility (Statute Miles) | 10 |
| Air Temperature at event time (in degrees celsius) | 24 |
| Dew Point at event time (in degress fahrenheit) | 14 |
| Wind Direction (degrees magnetic) | 210 |
| Variable Wind Indicator | Unknown |
| Wind Speed (knots) | 4 |
| Wind Velocity Indicator | Unknown |
| Wind Gust Indicator | Not Gusting |
| Wind Gust (knots) | 0 |
| Altimeter Setting at event time (in. Hg) | 29 |
| Density Altitude (feet) | -- |
| Intensity of Precipitation | Unknown |
| METAR weather report | -- |
| Event Highest Injury | None |
| On Ground, Fatal Injuries | 0 |
| On Ground, Minor Injuries | 0 |
| On Ground, Serious Injuries | 0 |
| Injury Total Fatal | -- |
| Injury Total Minor | -- |
| Injury Total None | 1 |
| Injury Total Serious | -- |
| Injury Total All | -- |
| Investigating Agency | NTSB |
| NTSB Docket Number (internal use) | 1721 |
| NTSB Notification Source | -- |
| NTSB Notification Date | Aug 25 1999 12:00AM |
| NTSB Notification Time | 30 |
| Fiche Number and/or location -used to find docket information | IMAGE |
| Date of most recent change to record | Aug 14 2001 1:55PM |
| User who most recently changed record | MONR |
| Basic weather conditions | Visual Meteorological Cond |
| FAA District Office | -- |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N999SJ |
| NTSB Number | LAX99LA283 |
| Missing Aircraft Indicator | N |
| 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 | UH-1B |
| Aircraft Series Identifier | UH-1B |
| Aircraft Serial Number | 1025 |
| Certified Max Gross Weight | 8500 |
| Aircraft Category | Helicopter |
| Aircraft Registration Class | U.S. Registered/U.S. Soil |
| 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 | Apr 24 1999 12:00AM |
| Airframe hours since last inspection | 43 |
| Airframe Hours | 7856 |
| ELT Installed | Unknown |
| ELT Activated | Unknown |
| ELT Aided Location of Event Site | Unknown |
| ELT Type | -- |
| Aircraft Owner Name | SAN JOAQUIN HELICOPTERS |
| Aircraft Owner Street Address | 1408 S. LEXINGTON |
| Aircraft Owner City | DELANO |
| Aircraft Owner State | CA |
| Aircraft Owner Country | |
| Aircraft Owner Zipcode | 93215 |
| Operator is an individual? | -- |
| Operator Name | |
| Operator Same as Owner? | Yes |
| Operator Is Doing Business As | -- |
| Operator Address Same as Owner? | Yes |
| Operator Street Address | |
| Operator City | |
| Operator State | |
| Operator Country | |
| Operator Zip code | |
| Operator Code | CUFE |
| Owner has at least one certificate | Yes - certificate holder |
| 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 | Unknown |
| Indicates Domestic or International Flight | Unknown |
| Operator carrying Pax/Cargo/Mail | Unknown |
| Type of Flying (Per_Bus / Primary) | Aerial Application |
| Second Pilot on Board | No |
| Departure Point Same as Event | Yes |
| Departure Airport Code | |
| Departure City | |
| Departure State | |
| Departure Country | |
| Departure Time | 2258 |
| Departure Time Zone | PDT |
| 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 | Takeoff |
| Report sent to ICAO? | -- |
| Evacuation occurred | -- |
| Date of most recent change to record | Jan 14 2001 10:25AM |
| User who most recently changed record | dbo |
| Since inspection or accident | -- |
| Event Location Runway Number and Location | 0 |
| Runway Length | -- |
| Runway Width | -- |
| Sight Seeing flight | No |
| Air Medical Flight | No |
| Medical Flight | -- |