Accident Details
On 27 September 2021, at approximately 18:50 local time, an unregistered powered deltaplane crashed near Kuusiku Airfield in Estonia. The aircraft struck trees near the end of the runway and fell among them. The pilot, a 46-year-old male, sustained minor injuries. The aircraft was destroyed.
Aircraft and Pilot Information
The aircraft consisted of an Aeros Stranger 2 wing, an Aeros cart, and a Rotax 582E engine. It was not registered and did not have a valid airworthiness certificate. The pilot did not hold a UL class A pilot license for ultralight aircraft but had approximately 150 hours of flight experience on a different deltaplane model (LaMouette Chronos 14). On the Aeros Stranger 2, he had only one hour of experience at the time of the accident.
Sequence of Events
At around 18:00, the pilot began training flights at Kuusiku Airfield. He performed touch-and-go landings on the upwind side of the runway, climbing to about 150 meters on each circuit. At approximately 18:48, during a touch-and-go, the pilot noticed another deltaplane with a passenger approaching the runway from the downwind side. He decided to give way, abort his landing, and perform a left turn while increasing altitude. He pushed the throttle to maximum, pulled the bar, and then leaned it to the right. The aircraft banked left and began losing altitude rapidly. The pilot then moved the bar left, but the descent did not stop. At an altitude of about 15 meters, the aircraft hit trees near the runway end and crashed.
Investigation Findings
The Safety Investigation Bureau (OJK) examined the wreckage and determined that all damage was caused by impact with trees and the ground. No technical failures or in-flight breakups were identified. The pilot could not recall checking the airspeed during the maneuver. Based on the factual evidence, the investigation concluded that the pilot exceeded the critical angle of attack for the prevailing airspeed, causing the wing to stall.
Probable Cause
The pilot allowed the wing to exceed the critical angle of attack at the prevailing airspeed, leading to an aerodynamic stall, loss of altitude, and collision with trees.