O'hare International Airport
Aircraft Accident/Incident Report

Chicago, Illinois 60666
Wednesday, December 1, 1999 14:31 CST

NTSB Narrative Summary Released at Completion of Accident

The airplane collided with the terminal building at the O'Hare International Airport. The captain reported he used the procedures in the BAE 146 Pilot Operating Handbook, to transfer fluid between the green and yellow hydraulic systems while the airplane was parked at the gate. He stated he then set the parking brake and checked the hydraulic system pressure. The captain reported they completed the before start, starting engines, and after engine start checklists at which time he signaled to the ramp personnel to remove the chocks. He reported the airplane then started to roll forward. He stated the parking brake was set and all four engines were running. The captain reported he tried the green braking and emergency yellow brake systems, however, the airplane continued to move. He then selected the anti-skid switch to battery and positioned the thrust levers to fuel off. The airplane traveled approximately 50 feet prior to contacting the bottom of the upper level of the terminal and a lower level door at gate B-20C. Postincident inspection of the brakes, hydraulic system, anti-skid system, squat switches, and related electrical system components failed to reveal why the airplane would have moved with the parking brake set. The initiation of the rolling event was not captured on the DFDR. The airplane is designed so that the DFDR does not record when the parking brake is set. On December 10, 1999, the operator issued an Alert Bulletin, prohibiting flight crews from performing hydraulic system fluid transfers. On August 25, 2000, the operator issued another Alert Bulletin, once again allowing flight crews to perform hydraulic system fluid transfers. On September 1, 2000, another Alert Bulletin was issued once again prohibiting flight crews from performing hydraulic system fluid transfers.

NTSB Probable Cause Narrative

An undetermined failure in the hydraulic system, which resulted in the airplane's entire braking system becoming temporarily inoperative. A factor associated with the incident was the airport terminal building that was contacted by the airplane.

Event Information

Type of Event Incident
Event Date 12/1/1999
Event Day of the Week Wednesday
Time of Event 1431
Event Time Zone Central Standard Time
Event City CHICAGO
Event State ILLINOIS
Event Country --
Zipcode of the event site 60666
Event Date Year 1999
Event Date Month 12
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude --
Event Location Longitude --
Event Location Airport O'HARE INTERNATIONAL
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 Unknown
Investigator's weather source Weather Observation Facility
Time of the weather observation 1356 Central Standard Time
Direction of event from weather observation facility (degrees) 0
Weather Observation Facility ID ORD
Elevation of weather observation facility 668
Distance of event from weather observation facility (units?) 0
Time Zone of the weather observation CST
Lighting Conditions Day
Lowest Ceiling Height 6000
Lowest Non-Ceiling Height 0
Sky/Lowest/Cloud Conditions Unknown
Sky Condition for Lowest Ceiling Overcast
Visibility Runway Visual Range (Feet) 0
Visibility Runway Visual Value (Statute Miles) 0
Visibility (Statute Miles) 10
Air Temperature at event time (in degrees celsius) 6
Dew Point at event time (in degress fahrenheit) -6
Wind Direction (degrees magnetic) 200
Variable Wind Indicator Unknown
Wind Speed (knots) 17
Wind Velocity Indicator Unknown
Wind Gust Indicator Unknown
Wind Gust (knots) 23
Altimeter Setting at event time (in. Hg) 30
Density Altitude (feet) --
Intensity of Precipitation Unknown
METAR weather report --
Event Highest Injury Minor
On Ground, Fatal Injuries 0
On Ground, Minor Injuries 1
On Ground, Serious Injuries 0
Injury Total Fatal --
Injury Total Minor 1
Injury Total None 48
Injury Total Serious --
Injury Total All 1
Investigating Agency NTSB
NTSB Docket Number (internal use) 10011
NTSB Notification Source --
NTSB Notification Date Dec 1 1999 12:00AM
NTSB Notification Time 1445
Fiche Number and/or location -used to find docket information IMAGE
Date of most recent change to record Jul 17 2001 8:35AM
User who most recently changed record MONR
Basic weather conditions Unknown
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N606AW
NTSB Number CHI00IA037
Missing Aircraft Indicator N
Federal Aviation Reg. Part Part 121: Air Carrier
Type of Flight Plan filed IFR
Flight plan Was Activated? --
Damage Minor
Aircraft Fire None
Aircraft Explosion None
Aircraft Manufacturer's Full Name British Aerospace
Aircraft Model BAE 146-200A
Aircraft Series Identifier BAE 146-20
Aircraft Serial Number E2033
Certified Max Gross Weight 91200
Aircraft Category Airplane
Aircraft Registration Class U.S. Registered/U.S. Soil
Aircraft is a homebuilt? No
Flight Crew Seats --
Cabin Crew Seats --
Passenger Seats --
Total number of seats on the aircraft 86
Number of Engines 4
Fixed gear or retractable gear Retractable
Aircraft, Type of Last Inspection Continuous Airworthiness
Date of Last Inspection Nov 27 1999 12:00AM
Airframe hours since last inspection --
Airframe Hours 27836
ELT Installed Yes
ELT Activated No
ELT Aided Location of Event Site Unknown
ELT Type --
Aircraft Owner Name WILMINGTON TRUST COMPANY
Aircraft Owner Street Address RODNEY SQUARE NORTH
Aircraft Owner City WILMINGTON
Aircraft Owner State DE
Aircraft Owner Country
Aircraft Owner Zipcode 19890
Operator is an individual? --
Operator Name AIR WISCONSIN
Operator Same as Owner? No
Operator Is Doing Business As --
Operator Address Same as Owner? No
Operator Street Address W6390 CHALLENGER DRIVE
Operator City APPLETON
Operator State WI
Operator Country
Operator Zip code 54914
Operator Code AWAA
Owner has at least one certificate Yes - certificate holder
Other Operator of large aircraft? No
Certified for Part 133 or 137 Operation Unknown
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) Unknown
Second Pilot on Board Yes
Departure Point Same as Event Yes
Departure Airport Code ORD
Departure City
Departure State
Departure Country
Departure Time 0
Departure Time Zone
Destination Same as Local Flt --
Destination Airport Code MLI
Destination City MOLINE
Destination State IL
Destination Country
Specific Phase of Flight Standing
Report sent to ICAO? --
Evacuation occurred --
Date of most recent change to record Jun 14 2001 4:03AM
User who most recently changed record dbo
Since inspection or accident --
Event Location Runway Number and Location 0
Runway Length --
Runway Width --
Sight Seeing flight No
Air Medical Flight No
Medical Flight --