What happened
On July 22, 2008, at 12:47 CDT, an Embraer Regional Jet 145, operating as American Eagle flight 4298 (N624AE), was departing runway 32L from taxiway M at Chicago O'Hare International Airport (ORD). Simultaneously, a Learjet 60, registration N252RP, was on final approach for runway 9R.
At 12:43 CDT, the tower local control controller instructed the E145 to taxi into position and hold on runway 3/2L, providing a wake turbulence advisory and an expected delay. At 12:44 CDT, the pilot of the N252RP reported being over the runway 9R outer marker and was cleared to land with instructions to plan a left turn on runway 32R during the landing roll.
At 12:45 CDT, the E145 was cleared for takeoff. As the E145 commenced its takeoff roll, the North Local Controller recognized a potential conflict and instructed the controller working the LC-10 position to "Stay low."
At 12:46 CDT, the North Local Controller instructed the N252RP to execute a go-around and maintain 4,000 feet due to the departing E145 traffic. During the go-around, the pilot of the N252RP observed the E145 on the takeoff roll. The LC-10 controller then advised the E145 crew to "stay low" due to traffic above them. Radar data and ASDE-X replay showed the N252RP passed over runway 32L with approximately 150 feet of lateral separation and 325 feet of vertical separation above the E145. The E145 pilot reported leveling the aircraft at approximately 200 feet above the runway to avoid a collision.
There were no injuries and no damage to either aircraft.
Findings
- The vertical separation between the two aircraft was approximately 200 feet.
- The ASDE-X system did not generate a visual or aural alert during the event because crossing runway logic was not installed.
- The weather at the time was visual meteorological conditions with 10 miles of visibility.