What happened
Condor Flight 610, operated by a McDonnell Douglas DC-10 with German registration D-AASO, was approximately two hours late as the crew prepared for departure. The flight was eventually cleared for takeoff with specific instructions to cross the five DME fix on the Standard Instrument Departure (SID) at or above 3,000 feet. Although the initial takeoff clearance was canceled, it was reissued about one minute later with the same altitude restrictions.
At the time of departure, the flight was exactly two hours overdue. Consequently, the air traffic control computer system dropped the flight plan data tag and block, as programmed to handle unused or overdue plans. After taking off, Flight 610 contacted departure control. The controller observed only a primary transponder target and noted that no altitude data was available for the aircraft.
Simultaneously, a Piper PA-42 with registration N900MP was conducting an Instrument Flight Rules (IFR) arrival for a visual approach to Pal-Waukee Airport at 2,800 feet. The two aircraft converged and passed each other with approximately 2 miles of horizontal separation and only 200 feet of vertical separation.
The investigation
Interviews with the air traffic controllers revealed that they had intended to climb Flight 610 to 5,000 feet as provided by the SID. However, this error was not noted because the flight plan data tag had been dropped from the computer display due to the flight's overdue status.
Findings
The incident highlights a critical failure in automated system monitoring where overdue flights lose their associated data tags, leading to controllers losing situational awareness of assigned altitudes. The lack of altitude data for the departing DC-10 contributed to the reduced vertical separation from the arriving Piper aircraft.