What happened
During a flight intended to drop eight parachutists from 13,000 feet, an aircraft experienced a sudden and catastrophic loss of control. As the aircraft approached the airport, the pilot requested a higher jump altitude due to cloud cover. During the approach, the aircraft's airspeed began to decrease. Approximately one kilometer from the designated jump point, the aircraft abruptly veered left and entered a steep descent.
In a dive exceeding 45 degrees, the aircraft descended 1,500 meters over a distance of less than one kilometer. The structural integrity of the aircraft type was compromised as airspeed and g-forces surpassed permissible limits, causing the plane to break up in mid-air. From an altitude of 2,000 meters, the wreckage fell nearly vertically at a velocity of approximately 60 m/s. The high g-forces and rapid rotations likely prevented the occupants from deploying their parachutes. All individuals on board sustained fatal injuries upon impact.
The investigation
SHK investigators examined the flight's operational parameters and the aircraft's stability. They found that the pilot lacked sufficient experience regarding both standard flight and parachute-specific operations. Crucially, the load sheet provided to the pilot lacked essential data regarding the individual weights of the parachutists or the total load mass, making it impossible to verify the aircraft's center of gravity.
The investigation established that the aircraft was tail-heavy, and the shifting center of gravity caused significant instability. Furthermore, the pilot faced a heavy workload while attempting to navigate to a precise point under difficult weather conditions. The presence of heavy clouds and the potential for hypoxia at high altitudes were also considered factors that may have impaired the pilot's capabilities.
Findings
- The aircraft became uncontrollable due to a combination of low airspeed, unstable flight caused by a tail-heavy configuration, and adverse weather conditions.
- The pilot's limited experience in managing flight without visual references and handling shifting centers of gravity prevented the recovery of the aircraft.
- A lack of standardized training and a lack of operational support systems contributed to the accident.
- There was no established system for determining the center of gravity before or during the jump operations.
Safety action
- EASA is advised to consider implementing formal training programs for pilots involved in parachute operations and to review mass and balance documentation approval procedures for such aircraft.
- The Swedish Transport Agency is recommended to ensure that appropriate loading instructions are implemented and followed for parachute jumps.
- Measures should be taken to ensure parachutists understand the impact of weight shifts on aircraft stability and that pilots receive the necessary support to maintain flight safety rules.