Airprox between SWR3962 and EWG583 near Kloten (D-BCRT)

Incident overview On 19 September 2000, an airprox occurred between SWR3962 and EWG583 approximately 5 NM west/southwest of the KLO DVOR/DME. The incident was recorded at 07:37 UTC. ## Aircraft and operations The first aircraft was SWR3962, a Boeing MD-83 registered HB-ISZ, operated by Swissair on a scheduled flight from Zürich to Basel. The second aircraft was EWG583, an ATR42-300 registered D-BCRT, operated by Eurowings on a scheduled flight from Zürich to Dortmund. ## Sequence of events EWG583 departed Zürich at 07:33:24 UTC and was cleared on the B3Y departure route. SWR3962 departed at 07:34:55 UTC on the H3Y departure route. Both aircraft were in radio contact with Zurich Departure Control on 125.950 MHz and were operating under instrument flight rules in Class C airspace. As SWR3962 climbed toward FL60, the crew received a TCAS resolution advisory and reduced their climb rate. EWG583 was not equipped with TCAS. The aircraft came within 1.7 NM horizontally and 600 ft vertically. ## Findings and cause The report found that the departure interval was 91 seconds, although the TACO system had suggested 3 minutes. The departure controller allowed the faster jet to depart behind the slower turboprop. The departure control controller initially assessed the situation as unproblematic but did not intervene. The probable cause was the controller's misjudgment of the traffic situation and passive behavior, with the unusually short departure interval contributing to the incident.