Individually Owned: 150,657
Corporate Owned: 137,281
Aircraft Accident/Incident Report
Anchorage, Alaska 99502
Sunday, December 5, 2004 14:00 AST
NTSB Narrative Summary Released at Completion of Accident
The 14 CFR Part 129 non-scheduled international cargo flight had a rapid decompression at 30,000 feet msl, and returned to the takeoff airport. An examination revealed an elliptical tear in the right side of the pressure bulkhead web separating the electronics service bay from the nose wheel well. The tear extended about 12-inches along a horizontal rivet line, with both ends of the torn skin turned downward approximately 80-90 degrees. The damaged area (STA 260-280, WL 160-170) was excised from the structure, and an examination of the fracture mechanism was conducted. The fracture examination disclosed that the web fracture was initiated by fatigue from multiple origins on the outboard web surface within the pressure vessel. Ten separate fatigue cracks propagated through the full web thickness before the onset of rapid ductile tearing. Each fatigue crack formed adjacent to a fastener hole common with the WL 170 beam, and was in line with the edge of the bonded strip doublers on the inboard surface (wheel well side). The web material met all the engineering specifications. At the time of the incident, the airplane had logged 58,185 flight hours, and 27,243 cycles/landings. Inspection criteria for the affected area is contained in a manufacturer's Service Bulletin and their Alert Revisions 1 thru 4. Following the examination of the incident airplane, Alert Revision 4 was amended to specify more frequent inspections of the affected area.
NTSB Probable Cause Narrative
The fatigue and subsequent fracture of a portion of the airplane's pressure bulkhead, which resulted in a rapid decompression during cruise flight.
Event Information
| Type of Event | Incident |
| Event Date | 12/5/2004 |
| Event Day of the Week | Sunday |
| Time of Event | 1400 |
| Event Time Zone | Atlantic Standard Time |
| Event City | Anchorage |
| Event State | ALASKA |
| Event Country | -- |
| Zipcode of the event site | 99502 |
| Event Date Year | 2004 |
| Event Date Month | 12 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | 611028N |
| Event Location Longitude | 1495947W |
| 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 | 1353 Atlantic Standard Time |
| Direction of event from weather observation facility (degrees) | -- |
| Weather Observation Facility ID | PANC |
| Elevation of weather observation facility | 152 |
| Distance of event from weather observation facility (units?) | -- |
| Time Zone of the weather observation | AST |
| Lighting Conditions | Day |
| Lowest Ceiling Height | 1100 |
| Lowest Non-Ceiling Height | 400 |
| Sky/Lowest/Cloud Conditions | Scattered |
| Sky Condition for Lowest Ceiling | Broken |
| Visibility Runway Visual Range (Feet) | -- |
| Visibility Runway Visual Value (Statute Miles) | -- |
| Visibility (Statute Miles) | 7 |
| Air Temperature at event time (in degrees celsius) | -11 |
| Dew Point at event time (in degress fahrenheit) | -12 |
| Wind Direction (degrees magnetic) | 30 |
| Variable Wind Indicator | Wind direction could be determined |
| Wind Speed (knots) | 5 |
| Wind Velocity Indicator | -- |
| Wind Gust Indicator | Not Gusting |
| Wind Gust (knots) | -- |
| Altimeter Setting at event time (in. Hg) | 29.65 |
| 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 | 3 |
| Injury Total Serious | -- |
| Injury Total All | -- |
| Investigating Agency | NTSB |
| NTSB Docket Number (internal use) | 19618 |
| NTSB Notification Source | FAA Anchorage, ROC |
| NTSB Notification Date | Dec 5 2004 12:00AM |
| NTSB Notification Time | 1415 |
| Fiche Number and/or location -used to find docket information | DMS |
| Date of most recent change to record | Feb 28 2006 4:11PM |
| User who most recently changed record | NTSB\JOHB |
| Basic weather conditions | Visual Meteorological Cond |
| FAA District Office | Anchorage, FSDO-03 |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | JA8158 |
| NTSB Number | ANC05IA016 |
| Missing Aircraft Indicator | -- |
| Federal Aviation Reg. Part | Part 129: Foreign |
| Type of Flight Plan filed | IFR |
| Flight plan Was Activated? | Yes |
| Damage | Minor |
| Aircraft Fire | None |
| Aircraft Explosion | None |
| Aircraft Manufacturer's Full Name | Boeing |
| Aircraft Model | 747SR-146B SF |
| Aircraft Series Identifier | -- |
| Aircraft Serial Number | 22711 |
| Certified Max Gross Weight | 750000 |
| Aircraft Category | Airplane |
| Aircraft Registration Class | -- |
| Aircraft is a homebuilt? | No |
| Flight Crew Seats | -- |
| Cabin Crew Seats | -- |
| Passenger Seats | -- |
| Total number of seats on the aircraft | 13 |
| Number of Engines | 4 |
| Fixed gear or retractable gear | Retractable |
| Aircraft, Type of Last Inspection | Continuous Airworthiness |
| Date of Last Inspection | -- |
| Airframe hours since last inspection | -- |
| Airframe Hours | 58179 |
| ELT Installed | Yes |
| ELT Activated | No |
| ELT Aided Location of Event Site | No |
| ELT Type | -- |
| Aircraft Owner Name | NIPPON CARGO AIRLINES |
| Aircraft Owner Street Address | Shiodome City Center 8F 5-2,Higashi-Shinbashi, |
| Aircraft Owner City | Minato-Ku, Tokyo |
| Aircraft Owner State | -- |
| Aircraft Owner Country | JA |
| Aircraft Owner Zipcode | 105-7108 |
| 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 | -- |
| Operator Zip code | -- |
| Operator Code | NIPF |
| 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 | International |
| Operator carrying Pax/Cargo/Mail | Cargo |
| Type of Flying (Per_Bus / Primary) | -- |
| Second Pilot on Board | Yes |
| Departure Point Same as Event | Yes |
| Departure Airport Code | PANC |
| Departure City | Anchorage |
| Departure State | AK |
| Departure Country | USA |
| Departure Time | -- |
| Departure Time Zone | ADT |
| Destination Same as Local Flt | -- |
| Destination Airport Code | NRT |
| Destination City | Tokyo-Narita |
| Destination State | -- |
| Destination Country | JA |
| Specific Phase of Flight | Cruise - normal |
| Report sent to ICAO? | Yes |
| Evacuation occurred | No |
| Date of most recent change to record | Sep 21 2005 1:28PM |
| User who most recently changed record | PETL |
| Since inspection or accident | Time of Accident |
| Event Location Runway Number and Location | NA |
| Runway Length | -- |
| Runway Width | -- |
| Sight Seeing flight | No |
| Air Medical Flight | No |
| Medical Flight | -- |