Serious incident to the Socata TB-20 ''Trinidad'' registered F-GGNZ and the Beechcraft 58 ''Baron'' registered F-GNSE on 13/10/2016 at Saint-Yan (Saône-et-Loire)
Quasi collision entre un avion dans le circuit d'aérodrome et un avion au décollage, tous deux en instruction
The pilot of the TB-20 took off for a local VFR flight from Saint Yan airport, with an instructor and another student pilot on board. On his return from the flight, he completed a first left-hand aerodrome traffic circuit to runway 33L, then slightly extended his climb to complete a U-shaped landing circuit to runway 33L. He was in radio contact with the tower controller.
The pilot of a TB-10, also operated by ENAC, took off from runway 33R for right-hand aerodrome traffic circuits. At the tower controller’s request, he extended the climb-out. When he requested a right turn, the controller instructed him to turn left into a remote crosswind leg.
At the holding point for runway 33R, the pilot of the Beechcraft 58 (Be-58) was preparing for an IFR training flight to Clermont-Ferrand (Puy-de-Dôme). He received clearance for departure from the ground controller for an omnidirectional departure towards RIMOR. This clearance was conditional on maintaining visual contact with the TB-10 that had just taken off. When the tower controller thought that the TB-10 was no longer in conflict, he cleared the Be-58 for take-off. The pilot took off then turned left in accordance with his clearance. He did not receive any information about the TB-20.
When the pilot of the TB-20 was on the downwind leg and the pilot of the Be-58 had turned left heading south-west, the pilot of the TB-20 suddenly saw the Be-58 approaching on his left. He performed a sudden evasive action. The Be-58 passed a few metres above the TB-20. The occupants of the Be-58 did not see the TB-20 and continued the flight. The instructor of the TB-20 requested to abort the flight and landed on runway 33R. He filed an AIRPROX report.
The investigation showed that the tower controller had an incorrect representation of the situation: in particular, he confused the TB-20 with the TB-10 in climb-out.
Poor visibility caused him to turn his attention to the radar display, which lagged behind the actual situation. He identified several potential conflicts based on an incorrect representation. For example, he identified a potential conflict between the Be-58 and the TB-10 in climb-out and asked the TB-10 to extend its climb on the centreline before clearing the Be-58 for take-off.
The crew of the TB-10 in climb-out for a right-hand circuit with clouds ahead, requested a right turn. The controller instructed them to turn left, not right. He thought he was talking to the crew of the TB-20, of whose position he had an inaccurate representation. He then announced to the crew of the Be-58 that the preceding aircraft was no longer in conflict and cleared them for take-off.
When the controller saw that the TB-10 had turned left into a crosswind leg, he initially thought that there was a conflict between the TB-10 and the TB-20. He did not identify the danger of the TB-20 and Be-58 crossing paths.