What happened
On June 21, 2017, a training flight was being conducted at Kętrzyn-Wilamowo Airport (EPKE) involving a student pilot and an instructor. The flight was part of a navigation training program for the student to obtain a UACP qualification. The aircraft, a 3Xtrim 450 – Ultra 23, was performing a landing on runway 25.
As the aircraft approached the threshold, it encountered a sudden upward surge of air. This caused the left wing to lift abruptly, inducing a right bank and a deviation from the runway centerline. In an attempt to correct the roll, the student pilot applied extreme left aileron input. The instructor attempted to intervene, but the student held the control stick so forcefully in the left position that the plastic handle broke.
The aircraft made a hard landing approximately 20 meters beyond the threshold, impacting the right main landing gear. The impact caused the right main gear to break, leading to a sequence of further impacts where the aircraft's wings struck the ground. The aircraft eventually slid along the runway, with the broken main gear digging into the surface. The accident resulted in extensive damage to the landing gear, engine cowlings, exhaust system, propeller, and engine mounts, as well as damage to the cockpit glazing. The crew exited the aircraft without injuries.
The investigation
The investigation, conducted by the operator, initially classified the event as an incident but later reclassified it as an accident. Investigators examined the flight path, the aircraft's structural failure, and the meteorological conditions at the time of the landing.
Findings
- The primary cause of the accident was the aircraft entering an asymmetric thermal updraft (thermal bubble) during the final approach, which violently lifted the left wing.
- The student pilot's reaction was delayed and overly aggressive, involving extreme and sustained left aileron input that contributed to the unstable flight path and subsequent hard landing.
- Contributing factors included strong turbulence during the approach and the pilot's handling of the sudden roll.
Safety action
Following the accident, the operator reviewed the event with all pilots operating from EPKE and reminded trainees of the importance of analyzing meteorological reports alongside real-time weather observations. Additionally, it was noted that during flights in the 3Xtrim 450 – Ultra 23, higher approach and rotation speeds should be utilized when cumulus clouds and high turbulence are expected.