What happened
On June 20, 2009, at approximately 11:13 UTC, an L 60S aircraft, registration OK-MJL, was performing a parachute jump operation at Chrudim Airport. After a successful initial flight, the aircraft took off for a second jump with a pilot and three passengers.
As the aircraft approached the deployment point at an altitude of approximately 1,050–1,100 m AGL, the aircraft experienced a sudden change in pitch and a left bank, followed by a right-hand roll and a loss of altitude. The aircraft entered a right-hand spin. During the first two rotations, the pilot ordered the passengers to exit the aircraft. The three skydivers successfully egressed the aircraft at an altitude of roughly 250–300 m AGL.
As the aircraft continued its descent, it entered a steep spiral dive. At approximately 100 m AGL, the aircraft transitioned into an inverted position and struck the ground at an angle of approximately 30 degrees. The impact resulted in the fatal injury of the pilot and a subsequent post-crash fire that destroyed the aircraft.
The investigation
The ÚZPLN investigation examined the aircraft's technical condition, the pilot's experience, and the aircraft's weight and balance. Investigators found that the aircraft's center of gravity (CG) was calculated at 34.4% SAT, which was 1.9% beyond the aft limit of the allowable range (26–32.5% SAT).
Technical examination of the wreckage revealed a broken rudder control cable. Forensic analysis showed that several strands of the cable had been damaged due to high pressure and friction within the rudder segment. This failure likely occurred when the pilot applied forceful rudder inputs in an attempt to recover from the spin. Additionally, investigators noted the absence of rudder stop bolts on the nose gear, which increased stress on the rudder control system.
Findings
- The aircraft's center of gravity was outside the permitted aft limit due to the weight and positioning of the passengers.
- The pilot likely failed to follow the procedures established in the L 60S flight manual for parachute jump operations, specifically regarding airspeed and flap configuration.
- The pilot likely reduced engine power during the approach to the drop zone, bringing the airspeed close to the aircraft's stall speed while the flaps were in the retracted position.
- A secondary failure of the rudder control cable occurred during the pilot's attempt to recover the aircraft from the spin.
- The pilot was fully aware of the situation and attempted to manage the emergency by ordering the passengers to exit.