What happened
On March 10, 2000, a Yakovlev YAK 52, registration LY-EST, was performing a recreational aerobatic flight near the Casarrubios del Monte airfield in Toledo, Spain. The flight, which included the pilot and one passenger, had been underway for approximately 40 minutes.
At approximately 17:30 local time, the pilot communicated his intention to perform a low pass over the runway before landing. After flying over the threshold of runway 08, the pilot initiated a steep climb at a 45-degree angle, reaching an altitude of roughly 300 feet. The aircraft then entered an inverted roll, maintaining an inverted attitude for approximately 25 to 30 seconds. During this period, the aircraft progressively lost altitude while following the runway axis. Just before impact, the aircraft leveled out from its inverted position, but it struck the terrain approximately 650 meters east of the runway 26 threshold. The impact caused the aircraft to slide 125 meters across a slope, resulting in a post-crash fire. The accident resulted in two fatalities.
The investigation
The investigation examined the aircraft's flight path, the wreckage, and the physiological factors affecting the pilot. Investigators noted that the aircraft's flight path involved high levels of vertical acceleration, with instrument indicators suggesting loads of +4g and -4g.
Analysis of the wreckage showed that the aircraft struck the ground with significant violence at an estimated speed of 200 km/h. The investigation also noted that the pilot's seatbelt, a three-point harness, was not sufficiently tight, which may have allowed the pilot to shift away from the controls during high-G maneuvers. Furthermore, the aircraft's airworthiness certificate from its country of registration did not explicitly authorize aerobatic flight within Spanish airspace.
Findings
- The primary cause of the accident was the sudden incapacitation of the pilot due to a loss of consciousness induced by high vertical acceleration during aerobatic maneuvers.
- The pilot's physiological tolerance to G-forces was likely reduced by several factors, including advanced age, smoking, and the recent ingestion of a heavy meal, which can divert blood flow away from the brain.
- The aircraft maintained an inverted attitude for an abnormally long duration (20–30 seconds), which is inconsistent with controlled flight and suggests the pilot was unresponsive.
- The aircraft was performing maneuvers that subjected the occupants to high vertical loads.
- The aircraft's registration status did not permit aerobatic operations in Spanish airspace.