On August 6, 2000 at 1300 central daylight time (CDT), an American Eagle ATR-42-2000, operating as flight 159 (EGF159) sustained no damage during a near midair collision with a United Airlines B-747 operating as flight 895 (UAL895) after takeoff from runway 22L at the O'Hare International Airport (ORD), Chicago, Illinois. The B-747 had been cleared for takeoff from runway 14R by the south local controller. EGF159 was subsequently cleared for takeoff on runway 22L by the third local control position (3LC). When EGF159 was rotating, the pilots observed the B-747 that was to their right, and airborne. EGF159 leveled off at 100 feet above ground level (agl) and the B-747 flew over the top of EGF159 with about 400 feet of vertical separation. Once the B-747 had passed, EGF159 resumed the climb and continued en route to it destination, Bloomington, Illinois. The flightcrew of UAL895 did not observe EGF159; nor did they receive an alert from the tower. The two pilots, flight attendant, and 46 passengers were not injured. UAL895 continued en route to Hong Kong. The two pilots, two augment pilots, 18 flight attendants, and 292 passengers were not injured. Visual meteorological conditions prevailed and both airplanes were operating on IFR flight plans. At 1754:04, the third local control (3LC) position that controlled runway 22L responded to a call from the driver of City of Chicago vehicle 845. The driver replied, "we're on delta and mike [taxiways] we're supposed to have a fox on two two left." The 3LC controller replied, "I've had no reports". When the driver of vehicle 845 asked if they should make a check of the runway, the controller responded, "I can't right now". At 1754:16, the flightcrew of UAL895 inquired of the south local controller that controlled 14R, "do you have any idea how long it'll be for eight ninety-five". The south local controller replied, "I'm trying to find out right now for you sir if you'll standby please". At 1754:41, the 3LC controller transmitted, "alright city eight four five just hold short of the two two left I'll get you on the runway as soon as this arrivals down". The driver acknowledged the call. At 1754:36, the 3LC controller transmitted, "city eight forty five I guess it's a box out there go ahead and ahh proceed on two two left let me know when you're done". The driver acknowledged the instruction. At 1757:09, the 3LC controller transmitted, "eagle flight one fifty nine two two left taxi into position and hold". The flightcrew acknowledged the instruction. At 1757:06, a conversation between the driver of city vehicle 845 and the 3LC controller ensued regarding the position of the debris on the runway. At 1757:21, the south local controller advised the flightcrew of UAL895, "...runway one four right taxi into position and hold traffic on an eight mile final the wind two one zero at eight traffic departs runway two seven left". The flightcrew acknowledged the clearance. At 1757:59, the driver of vehicle 845 advised the 3LC controller, "okay roger we just did the first sweep we didn't see anything we'll do a second one when you give us the chance". The 3LC controller replied, "city eight four five proceed on ahh four right let me know when you're done". At 1758:53, the south local controller transmitted, "United eight ninety-five heavy runway one four right turn left heading zero niner zero cleared for takeoff". At 1759:20, the driver of vehicle 845 advised, "tower...I'm gonna exit on sierra four I'm gonna standby in case you need me on sierra". The 3LC controller replied, "city eight four five thank you advise when you're clear". At 1759:30, the driver advised, "eight four five clear of two two left". At 1759:33, the 3LC controller transmitted, "eagle one fifty nine turn left heading one eight zero two two left cleared for takeoff". At 1759:37, the flightcrew acknowledged their takeoff clearance and the assigned heading. The 3LC controller was then relieved. At 1800:16, the relieving 3LC controller transmitted, "eagle one fifty nine traffic departing fourteen right". At 1800:19, the flightcrew replied, "ah we have him in sight sir". At 1800:20, the relieving controller at the south local control position transmitted, "United eight ninety five heavy contact departure one two five point zero so long". At 1801:10, the 3LC controller transmitted, "eagle one fifty nine come back to a two hundred heading if you would right to two zero zero and departures on one two seven point four two hundred on the heading". The flightcrew acknowledged the instructions. At 1800:24, the flightcrew of UAL895 transmitted, "twenty five zero for departure United eight ninety five heavy and ahh be advised there's ah quite a few hesitations in airspeed on takeoff". The south local controller acknowledged their transmission. The incident was classified by the air traffic control facility as an operational error. Following the incident, the facility developed new coordination measures between the air traffic controllers in the tower. (See Air Traffic Group Chairman's Factual Report)