What happened
On October 5, 2017, at 04:50 UTC, an Airbus A312-200 was climbing through FL100 after departing from Warsaw Chopin Airport (EPKT). During this phase of flight, the crew received two specific system alerts: an indication that the aft cargo door was open and a flight control aileron detection servo fault.
Following the alerts, the aircraft entered a holding pattern at FL100. After consulting with Maintenance Control Center (MCC), the crew decided to return to EPKT. To manage the aircraft's weight, the crew performed a fuel burn-off procedure. The aircraft subsequently landed at EPKT at 06:48. Due to the fuel management process, the landing weight was 76,500 kg, which was 1,000 kg above the maximum landing weight (MLW). The crew followed the overweight checklist during the approach.
The investigation
The investigation focused on the cause of the cockpit alerts and the impact of the landing weight. Upon landing, maintenance personnel conducted inspections of the aircraft systems. The investigation confirmed that the aft cargo door indication was caused by a faulty proximity sensor (32NV) responsible for signaling the door's closed status. Regarding the flight control alert, no malfunctions were detected in the aileron detection servo system.
Furthermore, technicians inspected the aircraft for signs of a hard landing resulting from the 1,000 kg exceedance of the MLW. Following the Aircraft Maintenance Manual (AMM) protocols, no structural damage or hard landing evidence was found. The aircraft was cleared for flight under the Minimum Equipment List (MEL) regarding the sensor fault.