Yesterday, 2 forum members noticed 2 Brussels Airlines Airbus A330 aircraft (OO-SFU and OO-SFN) flying above Belgian airspace. Luchtzak.be was curious and asked the question to Brussels Airlines.
A flight number SN9xxx marks a training flight, a positioning flight or a test flight. Yesterday, brand new Airbus Flight Control Computers were installed on both aircraft. Airbus pilots joined the Brussels Airlines technical pilots* on these flights to make 100% sure everything is working fine.
* a technical pilot is there to enhance liaisons between Flight Operations and Maintenance department, the technical pilot can also collect vital details for trouble shooting purposes and give engineers a better understanding of inflight problems. If there is a technical pilot position established in an airline, the FOM (flight operations manual) will provide details about the responsibilities and the tasks dedicated to him/her. Source: pprune.org
