Cat. 2 investigation report: simplified-format report, adapted to the circumstances of the occurrence and the investigation stakes.
When a Boeing 717 on an ILS approach was at 3 NM from the threshold of runway 05, and without other traffic to be managed on the frequency, the LOC controller proposed an immediate take-off to the crew of the CRJ700 who were approaching the holding point. Despite the information concerning the Boeing 717’s distance from the threshold and the GND controller’s comment which suggested that the separation between the two aeroplanes would not be ensured, the LOC controller remained confident in his choice to give priority to the take-off of the CRJ700 rather than to the landing of the Boeing 717. Observing that the CRJ700 would not have crossed the opposite end of the runway by the time they landed, the crew of the Boeing 717 executed a missed approach at a height of 240 ft and at 0.58 NM from the threshold of runway 05. The initial strategy of the LOC controller mainly relied on the capability of the crew of the CRJ700 to immediately follow his instructions. In the dynamic flight phases with a high workload and with a difference in acceleration between the two aeroplanes, it was difficult for the crews to perceive, analyse and follow the instructions from the LOC controller, especially since they were given in different languages. The difficulty with following the progress of each aeroplane from the control tower and the late appearance of the information on his radar screen did not allow the LOC controller to adapt his strategy. Moreover, the Boeing 717’s deviation to the west due to the crew selecting a heading which was different to the runway magnetic heading, accentuated the horizontal closing in of the two aeroplanes after the left turn made by the CRJ700.
The compliance with the TCAS resolution advisories by the two crews resolved the conflict.