Individually Owned: 150,657
Corporate Owned: 137,281
Hector International Airport
Aircraft Accident/Incident Report
Fargo, North Dakota 58104
Saturday, October 20, 2007 20:07 CDT
NTSB Narrative Summary Released at Completion of Accident
Shortly after departure, the flightcrew received a Brake and Steering Control Unit (BSCU) channel 2 fault message. Upon reaching 10,000 feet, the crew reset the BSCU per the cockpit operational manual (COM); however, the BSCU channel 2 fault returned and they could not turn off the auto brakes, nor could they change the brake setting from “Maximum.” The crew confirmed that they had “yellow” brake pressure (alternate brakes and parking brake), and believed that they would be landing with alternate brakes. Because turning the antiskid and nosewheel steering to the “Off” position would also turn off maximum braking, they discussed landing with the antiskid and nosewheel steering selected “Off” if necessary. When the crew extended the landing gear during the first approach, they received a landing gear shock absorber fault indication and the auto throttles and autopilot turned off. The crew then contacted air traffic control (ATC) and requested a climb to assess the situation. The captain stated that the landing gear remained down and the flaps were raised. The first officer continued to perform the procedures in the COM and contacted maintenance control to inform them of the landing gear shock absorber fault. The autopilot and auto throttles remained inoperative.
The flight crew then requested and received vectors to final approach. The captain stated that they set the flaps to full and completed the landing checklist. He stated that they planned to keep the brake pressure low during the landing and continue the landing roll with manual braking until they came to a stop. They then intended to turn the nosewheel steering on and taxi to the gate. The captain stated they anticipated an uneventful landing and did not advise ATC of the situation. After landing, the crew felt a vibration when the nosewheel touched down and ATC informed them of flames near the nose gear. The airplane came to rest on the runway with the nose gear strut turned 90 degrees to the direction of landing. The lower half of both the nose gear tire and wheel assembly was ground away due to runway contact. The nose gear was the only part of the airplane that sustained damage.
Postincident examination and testing of the nose landing gear systems revealed an unidentified and intermittent failure of an integrated circuit on the BSCU monitor board. This failure most likely resulted in frozen BSCU System 1 analog and discrete outputs. If the BSCU System 1 commands had frozen, the BSCU System 2 would have been able to detect the System 1 failure but would not have been able to take control. As a result of this incident, the aircraft and the nose gear manufacturers established a program intended to increase the reliability of the BSCU. Each issued a service bulletin for modification of the BSCU software and both the Federal Aviation Administration and European Aviation Safety Agency issued Airworthiness Directives that made compliance with the service bulletin mandatory.
NTSB Probable Cause Narrative
The failure of the Brake and Steering Control Unit, which allowed the nose landing gear to turn to the 90-degree position.
Event Information
| Type of Event | Incident |
| Event Date | 10/20/2007 |
| Event Day of the Week | Saturday |
| Time of Event | 2007 |
| Event Time Zone | Central Daylight Time |
| Event City | Fargo |
| Event State | NORTH DAKOTA |
| Event Country | -- |
| Zipcode of the event site | 58104 |
| Event Date Year | 2007 |
| Event Date Month | 10 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | 465514N |
| Event Location Longitude | 0964857W |
| Event Location Airport | Hector International |
| Event Location Nearest Airport ID | FAR |
| Indicates whether the acc/inc occurred off or on an airport | On Airport |
| 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 | 1953 Central Daylight Time |
| Direction of event from weather observation facility (degrees) | -- |
| Weather Observation Facility ID | FAR |
| Elevation of weather observation facility | 902 |
| Distance of event from weather observation facility (units?) | -- |
| Time Zone of the weather observation | CDT |
| Lighting Conditions | Night |
| Lowest Ceiling Height | -- |
| Lowest Non-Ceiling Height | 10000 |
| Sky/Lowest/Cloud Conditions | Few |
| 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) | 12 |
| Dew Point at event time (in degress fahrenheit) | 6 |
| Wind Direction (degrees magnetic) | 250 |
| Variable Wind Indicator | Wind direction could be determined |
| Wind Speed (knots) | 4 |
| Wind Velocity Indicator | -- |
| Wind Gust Indicator | Not Gusting |
| Wind Gust (knots) | -- |
| Altimeter Setting at event time (in. Hg) | 29.55 |
| 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 | 138 |
| Injury Total Serious | -- |
| Injury Total All | -- |
| Investigating Agency | NTSB |
| NTSB Docket Number (internal use) | 27818 |
| NTSB Notification Source | NWA |
| NTSB Notification Date | Oct 20 2007 12:00AM |
| NTSB Notification Time | -- |
| Fiche Number and/or location -used to find docket information | -- |
| Date of most recent change to record | Jan 27 2011 12:25PM |
| User who most recently changed record | broda |
| Basic weather conditions | Visual Meteorological Cond |
| FAA District Office | Fargo, ND FSDO |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N331NW |
| NTSB Number | CHI08IA022 |
| Missing Aircraft Indicator | -- |
| Federal Aviation Reg. Part | Part 121: Air Carrier |
| Type of Flight Plan filed | IFR |
| Flight plan Was Activated? | Yes |
| Damage | Minor |
| Aircraft Fire | None |
| Aircraft Explosion | None |
| Aircraft Manufacturer's Full Name | Airbus Industrie |
| Aircraft Model | A320-211 |
| Aircraft Series Identifier | -- |
| Aircraft Serial Number | 318 |
| Certified Max Gross Weight | 166400 |
| Aircraft Category | Airplane |
| Aircraft Registration Class | -- |
| Aircraft is a homebuilt? | No |
| Flight Crew Seats | 4 |
| Cabin Crew Seats | 5 |
| Passenger Seats | 148 |
| Total number of seats on the aircraft | 157 |
| Number of Engines | 2 |
| Fixed gear or retractable gear | Retractable |
| Aircraft, Type of Last Inspection | Continuous Airworthiness |
| Date of Last Inspection | Oct 15 2007 12:00AM |
| Airframe hours since last inspection | 48 |
| Airframe Hours | 47672 |
| ELT Installed | Yes |
| ELT Activated | No |
| ELT Aided Location of Event Site | No |
| ELT Type | Unknown |
| Aircraft Owner Name | Northwest Airlines |
| Aircraft Owner Street Address | 5101 Northwest Drive |
| Aircraft Owner City | St. Paul |
| Aircraft Owner State | MN |
| Aircraft Owner Country | USA |
| Aircraft Owner Zipcode | 55111 |
| Operator is an individual? | No |
| Operator Name | Northwest Airlines |
| Operator Same as Owner? | Yes |
| Operator Is Doing Business As | -- |
| Operator Address Same as Owner? | Yes |
| Operator Street Address | 5101 Northwest Drive |
| Operator City | St. Paul |
| Operator State | MN |
| Operator Country | USA |
| Operator Zip code | 55111 |
| Operator Code | NWAA |
| Owner has at least one certificate | Yes - certificate holder |
| 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 | Scheduled |
| Indicates Domestic or International Flight | Domestic |
| Operator carrying Pax/Cargo/Mail | Passenger Only |
| Type of Flying (Per_Bus / Primary) | -- |
| Second Pilot on Board | Yes |
| Departure Point Same as Event | No |
| Departure Airport Code | MSP |
| Departure City | MINNEAPOLIS |
| Departure State | MN |
| Departure Country | USA |
| Departure Time | 1911 |
| Departure Time Zone | CDT |
| Destination Same as Local Flt | crash at destination city |
| Destination Airport Code | FAR |
| Destination City | Fargo |
| Destination State | ND |
| Destination Country | USA |
| Specific Phase of Flight | Landing - roll |
| Report sent to ICAO? | -- |
| Evacuation occurred | -- |
| Date of most recent change to record | Oct 29 2010 12:05PM |
| User who most recently changed record | sulp |
| Since inspection or accident | Time of Accident |
| Event Location Runway Number and Location | 18 |
| Runway Length | 9000 |
| Runway Width | 150 |
| Sight Seeing flight | No |
| Air Medical Flight | No |
| Medical Flight | -- |