Accident Overview
A twin-engine aircraft was conducting a local skydiving mission with 17 skydivers and two pilots aboard. After takeoff, while climbing, both engines simultaneously suffered a total power loss. The commander reported that the failure did not induce any yaw, and the only warning lights that illuminated were those indicating double engine failure. Following the power loss, airspeed decayed rapidly, leading the commander to suspect that the automatic outboard wing spoilers had also deployed.
Forced Landing
Realizing that a forced landing was the only option, the commander initiated a steep descent to maintain airspeed and turned 90 degrees to the right to position the aircraft for a landing in a large field of corn stubble. The aircraft landed heavily in a slightly nose-up attitude with a slight right bank at an estimated speed of 170 km/h (92 knots). It slid to a stop, sustaining substantial damage to the fuselage, landing gear, wing struts, propellers, and wings.
Occupant Evacuation
All 19 occupants evacuated the cabin after the aircraft came to rest. None were injured.
Investigation Findings
The official investigation reported several findings. A latent defect in the electrical system caused the simultaneous total power loss when the flaps were retracted at 500 feet AGL during climb-out, along with automatic operation of both asymmetric spoiler systems. This defect was traced to progressive loosening of a single earthing screw that provided a common earth point for the flap electric signaling and propeller auto-feathering systems. The loosening resulted in high resistance to earth, causing both propellers to feather when flap retraction was selected, automatic closure of both engine fuel shut-off valves within the fuel control units, and extension of both outboard spoilers.
During manufacture in Poland, a single earthing point was installed that did not comply with the design requirements issued by the Antonov Design Bureau, which required dual combined earthing terminals for the flap signaling and propeller auto-feathering systems. Additionally, the Antonov Design Bureau had never cleared that aircraft type for flight with the aft clam-shell doors removed or for parachute training. The aircraft had been incorrectly granted an Aerial Work Permit for parachuting operations in the UK by the Department of Transport, assisted by the CAA, based on implicit reliance on submitted documentation that was later proven invalid.