Individually Owned: 150,657
Corporate Owned: 137,281
Chicago O'hare Intl Airport
Aircraft Accident/Incident Report
Chicago, Illinois 60666
Tuesady, October 9, 2007 20:30 CDT
NTSB Narrative Summary Released at Completion of Accident
The airplane's left main landing gear inboard and outboard anti skid tachometers wiring were reversed during scheduled maintenance at a vendor. During landing, the inboard left main landing gear's wheels went to a high braking level and the outboard wheel did not apply braking. The airplane sustained minor damage when it exited the runway and impacted runway lighting. Post incident examination of the airplane and brake components revealed no further anomalies. The vendor that performed the scheduled maintenance indicated that their personnel did not understand that the built in test equipment test they performed did not check for cross-wired tachometers. A different specified test called out in the airplane maintenance manual and in an operator's reference document indicated this specified check would verify a cross-wired condition. The operator reported that the reference documentation associated with the scheduled maintenance involving both of the left main landing gear's tachometers was unclear and that the procedure for that maintenance was revised.
NTSB Probable Cause Narrative
The misrouted and reversed antiskid wiring by vendor maintenance personnel leading to the runway excursion. Contributing to the incident were the runway sign, the vendor's maintenance personnel not understanding the entire maintenance procedures in the dual tachometer replacement, and the operator's maintenance procedures being unclear to the maintenance personnel.
Event Information
| Type of Event | Incident |
| Event Date | 10/9/2007 |
| Event Day of the Week | Tuesday |
| Time of Event | 2030 |
| Event Time Zone | Central Daylight Time |
| Event City | Chicago |
| Event State | ILLINOIS |
| Event Country | -- |
| Zipcode of the event site | 60666 |
| Event Date Year | 2007 |
| Event Date Month | 10 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | 415807N |
| Event Location Longitude | 0875428W |
| Event Location Airport | CHICAGO O'HARE INTL |
| Event Location Nearest Airport ID | ORD |
| 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 | 668 |
| Weather Briefing Completeness | -- |
| Investigator's weather source | Weather Observation Facility |
| Time of the weather observation | 1951 Central Daylight Time |
| Direction of event from weather observation facility (degrees) | -- |
| Weather Observation Facility ID | ORD |
| Elevation of weather observation facility | 668 |
| 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 | -- |
| 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) | 10 |
| Air Temperature at event time (in degrees celsius) | 16 |
| Dew Point at event time (in degress fahrenheit) | 4 |
| Wind Direction (degrees magnetic) | 300 |
| Variable Wind Indicator | Wind direction could be determined |
| Wind Speed (knots) | 17 |
| Wind Velocity Indicator | -- |
| Wind Gust Indicator | Gusting |
| Wind Gust (knots) | 23 |
| Altimeter Setting at event time (in. Hg) | 29.91 |
| Density Altitude (feet) | -- |
| Intensity of Precipitation | -- |
| METAR weather report | KORD 100051Z 30017G23KT 10SM CLR 16/04 A2991 RMK S |
| Event Highest Injury | Minor |
| On Ground, Fatal Injuries | -- |
| On Ground, Minor Injuries | -- |
| On Ground, Serious Injuries | -- |
| Injury Total Fatal | -- |
| Injury Total Minor | 2 |
| Injury Total None | 125 |
| Injury Total Serious | -- |
| Injury Total All | 2 |
| Investigating Agency | NTSB |
| NTSB Docket Number (internal use) | 24761 |
| NTSB Notification Source | FAA |
| NTSB Notification Date | Oct 9 2007 12:00AM |
| NTSB Notification Time | -- |
| Fiche Number and/or location -used to find docket information | -- |
| Date of most recent change to record | Oct 9 2008 4:44PM |
| User who most recently changed record | male |
| Basic weather conditions | Visual Meteorological Cond |
| FAA District Office | O'Hare FSDO |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N431UA |
| NTSB Number | CHI08IA026 |
| 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 | A320-232 |
| Aircraft Series Identifier | -- |
| Aircraft Serial Number | 571 |
| Certified Max Gross Weight | 169750 |
| 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 | 146 |
| Number of Engines | 2 |
| Fixed gear or retractable gear | Retractable |
| Aircraft, Type of Last Inspection | Continuous Airworthiness |
| Date of Last Inspection | Oct 1 2007 12:00AM |
| Airframe hours since last inspection | -- |
| Airframe Hours | 41163 |
| ELT Installed | Yes |
| ELT Activated | Unknown |
| ELT Aided Location of Event Site | Unknown |
| ELT Type | -- |
| Aircraft Owner Name | U S BANK NA TRUSTEE |
| Aircraft Owner Street Address | 25 ASYLUM AVE FL 23 |
| Aircraft Owner City | HARTFORD |
| Aircraft Owner State | CT |
| Aircraft Owner Country | USA |
| Aircraft Owner Zipcode | 06103 |
| Operator is an individual? | No |
| Operator Name | UNITED AIR LINES INC |
| Operator Same as Owner? | No |
| Operator Is Doing Business As | -- |
| Operator Address Same as Owner? | No |
| Operator Street Address | -- |
| Operator City | Chicago |
| Operator State | IL |
| Operator Country | USA |
| Operator Zip code | 60666 |
| Operator Code | UALA |
| 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 | SEA |
| Departure City | SEATTLE |
| Departure State | WA |
| Departure Country | USA |
| Departure Time | 1649 |
| Departure Time Zone | CDT |
| Destination Same as Local Flt | crash at destination city |
| Destination Airport Code | -- |
| Destination City | Chicago |
| Destination State | IL |
| Destination Country | USA |
| Specific Phase of Flight | Landing |
| Report sent to ICAO? | -- |
| Evacuation occurred | -- |
| Date of most recent change to record | Dec 16 2008 12:01PM |
| User who most recently changed record | johb |
| Since inspection or accident | Last Inspection |
| Event Location Runway Number and Location | 22R |
| Runway Length | 7500 |
| Runway Width | 150 |
| Sight Seeing flight | No |
| Air Medical Flight | No |
| Medical Flight | -- |