Individually Owned: 150,657
Corporate Owned: 137,281
O'hare International Airport
Aircraft Accident/Incident Report
Chicago, Illinois 60018
Monday, September 22, 2008 13:42 CDT
NTSB Narrative Summary Released at Completion of Accident
While performing the cockpit preflight, the captain noticed that the standby horizon was unpowered. After cycling the Standby Power Selector and the Battery Switch, the captain noted that five status messages were displayed on the engine indicating and crew alert system (EICAS) screen, although he could not remember the specific messages. Maintenance personnel subsequently cleared the messages and told the crew they were "good to go," without making a logbook entry. Approximately 30 minutes after takeoff several cockpit lights flickered; multiple EICAS messages appeared, including the AIR/GRD SYS caution message; the Standby Power OFF light illuminated; the autopilot disconnect warning sounded; and the autothrottles disconnected. The first officer referenced the STANDBY BUS OFF procedure in the QRH, turning the Standby Power selector to the BAT position. The QRH states that when BAT is selected the battery will provide bus power for approximately 30 minutes. Although the QRH did not instruct the crew to divert to the nearest suitable airport, it indicates that the battery will supply bus power for approximately 30 minutes and the captain reported to maintenance that the battery would be depleted. After consulting with company maintenance specialists, the crew elected to continue the flight. Battery power was depleted and numerous essential aircraft systems began to fail about 2 hours and 24 minutes after the flight crew switched the Standby Power selector to the BAT position. These systems included the stabilizer trim, the captain’s instrumentation, thrust reversers, anti-skid and others. The flight diverted to the closest airport, an emergency was declared, and the airplane was cleared to land on the 7,500-foot-long runway; the captain stated that due to problems controlling the airplane, he did not want to circle to land on a longer runway. The airplane touched down hard about 2,500 feet down the runway. The crew determined they were going to overrun the end of the runway, so the captain veered the airplane off the left side of the runway into the grass, where the airplane came to rest with seven of the eight main gear tires either blown out or deflated. Postaccident investigation revealed erosion on the B contacts within the K106 relay; a failure of the K106 electrical relay would result in the events described by the crew.
NTSB Probable Cause Narrative
The failure of an electrical relay due to eroded contacts and the flight crew's decision to continue a flight that was operating on battery power.
Event Information
| Type of Event | Incident |
| Event Date | 9/22/2008 |
| Event Day of the Week | Monday |
| Time of Event | 1342 |
| Event Time Zone | Central Daylight Time |
| Event City | Chicago |
| Event State | ILLINOIS |
| Event Country | -- |
| Zipcode of the event site | 60018 |
| Event Date Year | 2008 |
| Event Date Month | 9 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | 415843N |
| Event Location Longitude | 0875417W |
| Event Location Airport | O'Hare International Airport |
| 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 | -- |
| Weather Briefing Completeness | -- |
| Investigator's weather source | Weather Observation Facility |
| Time of the weather observation | 1351 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 | Day |
| Lowest Ceiling Height | 25000 |
| Lowest Non-Ceiling Height | 5000 |
| Sky/Lowest/Cloud Conditions | Few |
| Sky Condition for Lowest Ceiling | Broken |
| Visibility Runway Visual Range (Feet) | -- |
| Visibility Runway Visual Value (Statute Miles) | -- |
| Visibility (Statute Miles) | 10 |
| Air Temperature at event time (in degrees celsius) | 27 |
| Dew Point at event time (in degress fahrenheit) | 16 |
| Wind Direction (degrees magnetic) | -- |
| Variable Wind Indicator | Variable |
| Wind Speed (knots) | 6 |
| Wind Velocity Indicator | -- |
| Wind Gust Indicator | Not Gusting |
| Wind Gust (knots) | -- |
| Altimeter Setting at event time (in. Hg) | 30.32 |
| 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 | 192 |
| Injury Total Serious | -- |
| Injury Total All | -- |
| Investigating Agency | NTSB |
| NTSB Docket Number (internal use) | 26784 |
| NTSB Notification Source | FAA |
| NTSB Notification Date | -- |
| NTSB Notification Time | -- |
| Fiche Number and/or location -used to find docket information | -- |
| Date of most recent change to record | Jul 23 2010 4:26PM |
| User who most recently changed record | broda |
| Basic weather conditions | -- |
| FAA District Office | -- |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N197AN |
| NTSB Number | CHI08IA292 |
| 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 | BOEING |
| Aircraft Model | 757-223 |
| Aircraft Series Identifier | -- |
| Aircraft Serial Number | NT975 |
| Certified Max Gross Weight | 251000 |
| Aircraft Category | Airplane |
| Aircraft Registration Class | -- |
| Aircraft is a homebuilt? | No |
| Flight Crew Seats | 2 |
| Cabin Crew Seats | 7 |
| Passenger Seats | 188 |
| Total number of seats on the aircraft | 197 |
| Number of Engines | 2 |
| Fixed gear or retractable gear | Retractable |
| Aircraft, Type of Last Inspection | Continuous Airworthiness |
| Date of Last Inspection | Sep 21 2008 12:00AM |
| Airframe hours since last inspection | 3 |
| Airframe Hours | 22094 |
| ELT Installed | Yes |
| ELT Activated | No |
| ELT Aided Location of Event Site | No |
| ELT Type | C126 |
| Aircraft Owner Name | American Airlines, Inc. |
| Aircraft Owner Street Address | 433 Amon Carter Blvd |
| Aircraft Owner City | Ft. Worth |
| Aircraft Owner State | TX |
| Aircraft Owner Country | USA |
| Aircraft Owner Zipcode | 76155 |
| Operator is an individual? | No |
| Operator Name | American Airlines, Inc. |
| Operator Same as Owner? | Yes |
| Operator Is Doing Business As | -- |
| Operator Address Same as Owner? | Yes |
| Operator Street Address | 433 Amon Carter Blvd |
| Operator City | Ft. Worth |
| Operator State | TX |
| Operator Country | USA |
| Operator Zip code | 76155 |
| Operator Code | AALA |
| 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 | 801 |
| Departure Time Zone | PDT |
| Destination Same as Local Flt | -- |
| Destination Airport Code | JFK |
| Destination City | New York |
| Destination State | NY |
| Destination Country | USA |
| Specific Phase of Flight | -- |
| Report sent to ICAO? | -- |
| Evacuation occurred | -- |
| Date of most recent change to record | Aug 25 2010 10:54AM |
| User who most recently changed record | broda |
| Since inspection or accident | Time of Accident |
| Event Location Runway Number and Location | 22R |
| Runway Length | 7500 |
| Runway Width | 150 |
| Sight Seeing flight | No |
| Air Medical Flight | No |
| Medical Flight | -- |