Aircraft Accident/Incident Report

Chicago, Illinois 60018
Thursday, March 23, 2006 9:07 CST

NTSB Narrative Summary Released at Completion of Accident

On March 23, 2006, at 0907 Central Standard Time, a runway incursion occurred between United Airlines (UAL) flight 604, a Boeing 737-300, and UAL1520, an A-320, at Chicago O'Hare International Airport (ORD) during daylight visual meteorological conditions. The north local controller cleared UAL604 for takeoff from runway 4L while UAL1520 was crossing the runway. The UAL604 co-pilot looked out the window and saw the A320 moving at a fast rate toward the runway, aborted the takeoff, and advised the controller that they were aborting their takeoff for the crossing traffic. The co-pilot stated that they did not get above taxi speed during their departure. Separation was lost with closest proximity of approximately 600 feet, the distance from approach end of runway 4L to taxiway H. AMASS did not activate.

NTSB Probable Cause Narrative

The probable cause of this incident was the ORD tower local controller's failure to provide sufficient separation between two aircraft departing intersecting runways. Contributing to the incident was the ORD local monitor's failure to monitor the situating and advise the local controller of the developing situation.

Event Information

Type of Event Incident
Event Date 3/23/2006
Event Day of the Week Thursday
Time of Event 907
Event Time Zone Central Standard Time
Event City Chicago
Event State ILLINOIS
Event Country --
Zipcode of the event site 60018
Event Date Year 2006
Event Date Month 3
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude --
Event Location Longitude --
Event Location Airport --
Event Location Nearest Airport ID --
Indicates whether the acc/inc occurred off or on an 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
Direction of event from weather observation facility (degrees) --
Weather Observation Facility ID KORD
Elevation of weather observation facility --
Distance of event from weather observation facility (units?) --
Time Zone of the weather observation --
Lighting Conditions --
Lowest Ceiling Height 2600
Lowest Non-Ceiling Height --
Sky/Lowest/Cloud Conditions --
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) 4
Dew Point at event time (in degress fahrenheit) -3
Wind Direction (degrees magnetic) 70
Variable Wind Indicator Wind direction could be determined
Wind Speed (knots) 4
Wind Velocity Indicator --
Wind Gust Indicator Unknown
Wind Gust (knots) --
Altimeter Setting at event time (in. Hg) 30.25
Density Altitude (feet) --
Intensity of Precipitation --
METAR weather report --
Event Highest Injury None
On Ground, Fatal Injuries 0
On Ground, Minor Injuries 0
On Ground, Serious Injuries 0
Injury Total Fatal --
Injury Total Minor --
Injury Total None 121
Injury Total Serious --
Injury Total All --
Investigating Agency NTSB
NTSB Docket Number (internal use) 22752
NTSB Notification Source FAA
NTSB Notification Date Mar 23 2006 12:00AM
NTSB Notification Time --
Fiche Number and/or location -used to find docket information DMS
Date of most recent change to record Nov 30 2007 3:42PM
User who most recently changed record NTSB\lema
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft #2

Aircraft Registration Number -- --
NTSB Number OPS06IA007A OPS06IA007B
Missing Aircraft Indicator -- --
Federal Aviation Reg. Part -- --
Type of Flight Plan filed IFR IFR
Flight plan Was Activated? Yes Yes
Damage None None
Aircraft Fire None None
Aircraft Explosion None None
Aircraft Manufacturer's Full Name Boeing Airbus Industrie
Aircraft Model 737-300 320-200
Aircraft Series Identifier -- --
Aircraft Serial Number -- --
Certified Max Gross Weight -- --
Aircraft Category Airplane Airplane
Aircraft Registration Class -- --
Aircraft is a homebuilt? No No
Flight Crew Seats -- --
Cabin Crew Seats -- --
Passenger Seats -- --
Total number of seats on the aircraft -- --
Number of Engines -- --
Fixed gear or retractable gear Fixed Fixed
Aircraft, Type of Last Inspection -- --
Date of Last Inspection -- --
Airframe hours since last inspection -- --
Airframe Hours -- --
ELT Installed -- --
ELT Activated -- --
ELT Aided Location of Event Site -- --
ELT Type -- --
Aircraft Owner Name -- --
Aircraft Owner Street Address -- --
Aircraft Owner City -- --
Aircraft Owner State -- --
Aircraft Owner Country -- --
Aircraft Owner Zipcode -- --
Operator is an individual? -- --
Operator Name -- --
Operator Same as Owner? -- --
Operator Is Doing Business As -- --
Operator Address Same as Owner? -- --
Operator Street Address P.O. Box 66100 P.O. Box 66100
Operator City Chicago Chicago
Operator State IL IL
Operator Country USA USA
Operator Zip code 60666 60666
Operator Code UALA UALA
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 Scheduled Scheduled
Indicates Domestic or International Flight Domestic Domestic
Operator carrying Pax/Cargo/Mail Passenger Only Passenger Only
Type of Flying (Per_Bus / Primary) -- --
Second Pilot on Board -- --
Departure Point Same as Event Yes Yes
Departure Airport Code KORD KORD
Departure City Chicago Chicago
Departure State IL IL
Departure Country USA USA
Departure Time -- --
Departure Time Zone CST CST
Destination Same as Local Flt -- --
Destination Airport Code KDCA KMCO
Destination City Washington Orlando
Destination State DC FL
Destination Country USA USA
Specific Phase of Flight Takeoff - aborted Taxi - to takeoff
Report sent to ICAO? -- --
Evacuation occurred -- --
Date of most recent change to record Nov 19 2007 6:59PM Nov 19 2007 6:59PM
User who most recently changed record ROWS ROWS
Since inspection or accident -- --
Event Location Runway Number and Location -- --
Runway Length -- --
Runway Width -- --
Sight Seeing flight No No
Air Medical Flight No No
Medical Flight -- --