What happened
On April 10, 2018, at approximately 17:05 UTC, a Cessna 152, registration OK-HAD, and a Bristell ELSA, registration OK-WAR 18, were involved in a serious near-collision during the landing phase at Letňany Airport (LKLT).
Both aircraft had departed from the airport and were performing VFR flight. While approaching the airport via point MIKE, the Cessuna 152 significantly deviated from its intended course, turning approximately 70 degrees to the right. This maneuver caused the aircraft to cross the trajectory of the Bristell ELSA and eventually position itself behind and below the lead aircraft.
As the Bristell ELSA was on its final approach to runway 23R, the Cessna 152 approached at a much higher speed (approximately 100 kt compared to the lead aircraft's 70 kt) and at a lower altitude. Approximately 0.9 km before the threshold of runway 23L, the Cessna 152 flew underneath the Bristell ELSA with a vertical separation of only about 10 to 15 meters. The pilot of the Bristell ELSA performed an immediate evasive maneuver to runway 23L to avoid the collision. The pilot of the Cessna 152 realized the danger only at the last moment and landed to the right of runway 23R, off the paved surface.
The investigation
The ÚZPLN investigation examined the flight tracks, radio communications, and the actions of the flight crew and AFIS dispatcher. The investigation established that the Cessna 152 pilot had received information regarding preceding traffic and her landing sequence but failed to maintain adequate separation. The investigation also noted that the AFIS dispatcher, due to sun glare on the tower windows, was unable to visually confirm the position of the Cessna 152 and therefore did not issue a verbal warning.
Findings
- The primary cause of the incident was the improper distribution of attention by the pilot of the Cessna 152, which resulted in a failure to timely detect the imminent collision with the aircraft ahead.
- The Cessna 152 approached the Bristell ELSA from behind and below on a nearly parallel trajectory with a significant speed differential.
- The pilot of the Cessna 152 was likely focused on the landing configuration and checklist, causing the lead aircraft to move into a blind spot.
- The aircraft were not equipped with electronic collision avoidance systems, such as FLARM.
- Environmental factors, including sun glare at the tower, prevented the AFIS dispatcher from visually identifying the trailing aircraft and issuing a warning.