Incident Overview
On 31 March 2019 at approximately 12:13 UTC, a serious incident involving a potential collision occurred between two aircraft at Letňany Airport (LKLT). The aircraft were a Cessna 172S, registration OK-COK, and a Bristell ELSA, registration OK-WAR 18. Both aircraft subsequently landed without damage. The incident was investigated by the Czech Accident Investigation Institute (ÚZPLN).
Flight Details
The Bristell ELSA was conducting a VFR flight from Ústí nad Labem to LKLT. At 12:08:37, the pilot reported at Neratovice, approximately 16 km from the airport, requesting direct entry to the control zone for landing. The AFIS controller instructed the pilot to continue to the circuit for runway 05R. The pilot acknowledged and proceeded toward the second circuit turn of runway 05R.
The Cessna 172S, with an instructor and a student pilot, was performing circuit training on runway 05R. At 12:09:32, the instructor reported position in the third circuit turn. The AFIS controller informed them they were first for landing on runway 05. After a low pass, the crew began the first circuit turn at 12:13:14 at an altitude of 1900 ft AMSL.
Near Collision
According to operational records, the potential collision resulted from the aircraft approaching each other initially head-on without the pilots' awareness. The Cessna 172S, at 80 kt after the first turn, and the Bristell, entering the second turn at 90 kt, converged. At 12:13:19, the vertical separation was approximately 125 ft. At 12:13:23, the Bristell passed about 75 m in front of the Cessna, with a height difference of 125 ft. The student pilot in the Cessna spotted the Bristell passing below. The instructor immediately executed a 360° turn to create separation. The Bristell pilot, who had begun descending from 1800 ft AMSL, reported seeing the Cessna and asked if they wanted to go ahead. The instructor announced a 360° turn downwind.
Pilot Statements
The Bristell pilot stated that upon seeing the Cessna, he turned right and descended from 1850 ft to 1700 ft. He admitted it was his fault for not giving way, but noted he lacked current information on the Cessna's position, had been blinded by the sun, and was focused on entering the circuit and making radio calls. He acknowledged he should have requested more detailed traffic information and reported his circuit entry earlier.
The instructor in the Cessna reported that after a low pass, the student was practicing circuit procedures. The instructor was monitoring for traffic from the Mike point but did not see the Bristell until the student alerted him just before the second turn. The Bristell entered the circuit without any radio call.
AFIS Communication
The AFIS controller stated that the Bristell pilot reported inbound from Neratovice and was instructed to continue to the circuit for runway 05R. The controller did not provide traffic information because the Bristell was not visible from the AFIS position.