What happened
On a return flight from Barcelona to Kaliningrad, a Boeing 737-3Y0, registration EI-DON, operated by KD Avia, encountered technical difficulties during its night approach. The flight, carrying 138 passengers and six crew members, was descending in heavy rain and gusty crosswinds. During the deployment of flaps, the crew received a flap asymmetry warning. In an attempt to resolve the alert, the captain took control and adjusted the flaps to a 2-degree position, which stopped the warning.
After notifying Kaliningrad controllers of the mechanical issue, the crew followed the Quick Reference Handbook (QRH). During this process, the co-pilot engaged the flap and gear inhibit switches, which inadvertently deactivated the ground-proximity warning system (GPWS). As the aircraft prepared for a high-speed landing, the crew calculated a landing speed of 161 knots.
During the final stages of the approach, a landing gear warning horn sounded due to the specific combination of engine power and flap settings. Although the horn sounded again when power was reduced to idle, the crew did not respond to the alert. Consequently, the aircraft performed a gear-up landing, sliding for 1,440 meters along the runway before coming to a stop. There were no fatalities reported in the accident.
Findings
Investigations into the mechanical failure revealed that a faulty Flap Position Transmitter was responsible for the asymmetry warning. While the flaps had actually reached the commanded position, the sensor provided incorrect data to the system. Notably, this specific sensor had been replaced earlier on the same day, and the aircraft EI-DON had experienced similar issues in the past.