Individually Owned: 150,657
Corporate Owned: 137,281
Madera Municipal Airport
Aircraft Accident/Incident Report
Madera, California 93638
Thursday, February 19, 2004 15:20 PST
NTSB Narrative Summary Released at Completion of Accident
The pilot executed an autorotative emergency landing following the failure of the number 6 tail rotor drive shaft hangar bearing while maneuvering. The check pilot and pilot were maneuvering the helicopter when it shuddered momentarily, followed by a heavier airframe vibration. The helicopter rolled left as it climbed to 500 feet. The check pilot attempted to turn right towards the airport; however, the helicopter rolled to the left again. The check pilot regained control, shut the engine down, and completed an autorotation to a field. The tail rotor drive shaft coupling was supported by the aft hangar bearing, and inspection revealed that it had sheared in torsional overload due to an overheated and seized number 6 hangar bearing. Post accident examination revealed that the hangar bearing inner race and the balls had large heat affected zones from overheating during operation (the metal in the races ball path had been molten and then had resolidified). The grease was also black and dry, with imbedded metal particles. A series of service bulletins, alert service bulletins, and airworthiness directives (including an emergency AD issued by the FAA) had been issued beginning in October 2001 through 2004 concerning the overheating and failure of the hangar bearings. The bulletins and airworthiness directives dealt with, in part, the modification of the helicopter to include cooling ducts and changes to existing bearings to prevent overheating and eventual bearing failure. The ADs mandated inspections of the hangar bearings every 25 hours of flight; bearing replacement before further flight was called out if metal particles or "black" grease was observed at any bearing.
NTSB Probable Cause Narrative
the failure of the number 6 hangar bearing due to overheating. A factor in the accident was the operator's likely inadequate compliance with service bulletins and airworthiness directives on this issue, along with an inadequate maintenance inspection program for the bearings.
Event Information
| Type of Event | Incident |
| Event Date | 2/19/2004 |
| Event Day of the Week | Thursday |
| Time of Event | 1520 |
| Event Time Zone | Pacific Standard Time |
| Event City | Madera |
| Event State | CALIFORNIA |
| Event Country | -- |
| Zipcode of the event site | 93638 |
| Event Date Year | 2004 |
| Event Date Month | 2 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | 365919N |
| Event Location Longitude | 1200646W |
| Event Location Airport | Madera Municipal |
| Event Location Nearest Airport ID | MAE |
| Indicates whether the acc/inc occurred off or on an airport | Off Airport/Airstrip |
| Distance from airport in statute miles | 1 |
| Degrees magnetic from airport | 300 |
| Airport Elevation | 253 |
| Weather Briefing Completeness | Full |
| Investigator's weather source | Weather Observation Facility |
| Time of the weather observation | 1553 Pacific Standard Time |
| Direction of event from weather observation facility (degrees) | 300 |
| Weather Observation Facility ID | MAE |
| Elevation of weather observation facility | 253 |
| Distance of event from weather observation facility (units?) | 1 |
| Time Zone of the weather observation | PST |
| 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) | 8 |
| Air Temperature at event time (in degrees celsius) | 13 |
| Dew Point at event time (in degress fahrenheit) | 8 |
| Wind Direction (degrees magnetic) | -- |
| Variable Wind Indicator | Variable |
| Wind Speed (knots) | 3 |
| Wind Velocity Indicator | -- |
| Wind Gust Indicator | Not Gusting |
| Wind Gust (knots) | -- |
| Altimeter Setting at event time (in. Hg) | 30.13 |
| 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) | 17978 |
| NTSB Notification Source | FAA |
| NTSB Notification Date | Feb 23 2004 12:00AM |
| NTSB Notification Time | 1200 |
| Fiche Number and/or location -used to find docket information | DMS |
| Date of most recent change to record | Jul 7 2005 10:33AM |
| User who most recently changed record | NTSB\JOHB |
| Basic weather conditions | Visual Meteorological Cond |
| FAA District Office | WP-FAT-FSDO |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N601MT |
| NTSB Number | LAX04IA135 |
| Missing Aircraft Indicator | -- |
| Federal Aviation Reg. Part | Part 91: General Aviation |
| Type of Flight Plan filed | None |
| Flight plan Was Activated? | No |
| Damage | Minor |
| Aircraft Fire | None |
| Aircraft Explosion | None |
| Aircraft Manufacturer's Full Name | Bell |
| Aircraft Model | 407 |
| Aircraft Series Identifier | -- |
| Aircraft Serial Number | 53428 |
| Certified Max Gross Weight | 5250 |
| 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 | 5 |
| Number of Engines | 1 |
| Fixed gear or retractable gear | Fixed |
| Aircraft, Type of Last Inspection | Continuous Airworthiness |
| Date of Last Inspection | Jan 29 2004 12:00AM |
| Airframe hours since last inspection | 34.2 |
| Airframe Hours | 1681.3 |
| ELT Installed | Yes |
| ELT Activated | No |
| ELT Aided Location of Event Site | No |
| ELT Type | -- |
| Aircraft Owner Name | Med Trans Corp |
| Aircraft Owner Street Address | 2301 University Drive Blg 1652-48 |
| Aircraft Owner City | Bismark |
| Aircraft Owner State | ND |
| Aircraft Owner Country | USA |
| Aircraft Owner Zipcode | 58502 |
| Operator is an individual? | No |
| 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 | USA |
| Operator Zip code | -- |
| Operator Code | M3XA |
| Owner has at least one certificate | -- |
| 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) | Instructional |
| Second Pilot on Board | Yes |
| Departure Point Same as Event | Yes |
| Departure Airport Code | -- |
| Departure City | Madera |
| Departure State | CA |
| Departure Country | USA |
| Departure Time | 1400 |
| Departure Time Zone | PST |
| 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 | Maneuvering |
| Report sent to ICAO? | No |
| Evacuation occurred | No |
| Date of most recent change to record | Feb 2 2009 1:40PM |
| User who most recently changed record | johb |
| Since inspection or accident | -- |
| Event Location Runway Number and Location | 120 |
| Runway Length | 5544 |
| Runway Width | 150 |
| Sight Seeing flight | No |
| Air Medical Flight | Yes |
| Medical Flight | -- |