What happened
On September 14, 2016, an Embraer ERJ-175 operated by PLL LOT SA experienced an incident during its approach to landing at Moscow Sheremetyevo Airport. During the approach, the aircraft's Ram Air Turbine (RAT), which serves as an emergency power source, deployed automatically without command.
Despite the unexpected deployment of the emergency generator, the flight crew performed a normal landing at the airport. Following the landing, the airline's Maintenance Control Center (MCC) was notified of the malfunction.
The investigation
An investigation was conducted by the operator. Following the incident, an Alitalia line mechanic was summoned to the aircraft. Utilizing the Aircraft Maintenance Manual (AMM), the mechanic successfully retracted the RAT. The return flight to Warsaw proceeded with a delay but was completed without further operational disruptions. An Aviation Safety Report (ASR) was filed regarding the event.