Casualties unknown

Two Aircraft Cleared for Takeoff on Crossing Runways at Chicago O'Hare (N635US)

Chicago, IL, US

On February 19, 1988, a Boeing 747-227B (registration N635US) was involved in an aviation accident near Chicago, IL. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive; 7 related events involving the same aircraft type or operator are linked below.

Sourcesthe U.S. National Transportation Safety Board (NTSB) historical archivePrimary reportUpdated 2026-06-10Data APIEditorial standards
Boeing 747-227B
Photo: Tosaka / CC BY 3.0, via Wikimedia Commons

Northwest Flight 3 (Boeing 747) and Air Wisconsin Flight 925 (BAE 146) were cleared for takeoff on crossing runways at Chicago-O'Hare, passing with an estimated 3000-4000 ft separation. The tower supervisor had not ensured coordination between local control positions.

Incident Details

On an unspecified date, Northwest Airlines Flight 3, a Boeing 747 registered as N635US, was cleared for takeoff on Runway 14R at Chicago-O'Hare International Airport. Simultaneously, Air Wisconsin Flight 925, a BAE 146 registered as N602AW, was cleared for takeoff on Runway 22L. The two aircraft subsequently passed each other with an estimated separation of 3000 to 4000 feet.

Contributing Factors

According to the investigation, the operational error occurred after the tower supervisor had not assured coordination between the North and South Local Control positions. At the time of the incident, the tower supervisor was acting as both the supervisor and the tower cab coordinator.

Aircraft and Operator Information

Northwest Airlines operated the Boeing 747 (N635US) on Flight 3. Air Wisconsin operated the BAE 146 (N602AW) on Flight 925. Both aircraft were cleared for takeoff at the same time on intersecting runways.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001213X25026. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.