First Officer: In commercial aviation, the first officer is the second pilot (sometimes referred to as the "co-pilot") of an aircraft. The first officer is second-in-command of the aircraft, to the captain who is the legal commander. In the event of incapacitation of the captain, the first officer will assume command of the aircraft.
The Flight Engineer: is primarily concerned with the operation and monitoring of all aircraft systems, and is required to diagnose and where possible rectify or eliminate any faults that may arise.




