Description
On 22 October 2020, an airprox (serious incident) occurred near Venlo glider airfield involving two gliders: a PZL-Bielsko SZD-51-1 Junior (registration PH-980) and an Alexander Schleicher ASK 21 (registration PH-1606). Both aircraft were flying close to the circuit starting point to join the left-hand circuit for runway 29. Visibility exceeded 10 kilometres. The Junior was at an altitude of 220 metres when its pilot observed the ASK 21 approaching from the right at approximately the same altitude. The pilot of the Junior initiated a 360-degree left turn to avoid a collision. The ASK 21 made a right-hand turn toward the downwind leg. The pilot of the Junior then followed the ASK 21 into the circuit and informed the occupants of the ASK 21 via radio that he was flying behind them, low, and requested they take the outside bend. Receiving no response, on the base leg the Junior flew past and in front of the ASK 21. Both gliders completed a safe landing.
Pilot Statements and Visibility
The pilot of the Junior stated that he had only seen the ASK 21 at the last moment because the aircraft was approaching head-on. Previously, no movement of the ASK 21 had been visible to him until it turned right to join the circuit. From the perspective of the Junior, the visible surface of the ASK 21 was minimal. The instructor and trainee in the ASK 21 stated that they had not seen the Junior close to the circuit starting point. The minimal contrast between the white gliders and the pale blue-white sky was noted as a factor in the late observation or non-observation of the aircraft.
Equipment Defects
In neither aircraft had the FLARM collision avoidance system issued a warning. The FLARM in the ASK 21 was defective. The occupants of the ASK 21 had not heard the radio call from the Junior because the transmitter of the Junior's radio was not working correctly. Both defects were known before the start of the flight. The gliding club's Safety Committee (VC) investigated the occurrence and shared findings with the Dutch Safety Board. The occurrence was reported to the Dutch Safety Board on 3 April 2021.
Classification and Cause
The incident was classified as a serious incident (reference 2020096). The airprox occurred because the pilots observed each other late or not at all. The pilot of the Junior performed an adequate evasive maneuver, avoiding a collision. In accordance with right-of-way rules (SERA.3210), the Junior was required to give way to the ASK 21, as it was on the right-hand side with intersecting headings at similar altitude.