Final answer:
The operational requirement that must be observed when ferrying a large, turbine engine powered airplane with one inoperative engine is maintaining a safe center of gravity.
Step-by-step explanation:
When ferrying a large, turbine engine powered airplane with one inoperative engine, the operational requirement that must be observed is maintaining a safe center of gravity. The center of gravity is the point where the weight of the aircraft is balanced. In a twin-engine aircraft, if one engine is inoperative, it creates an imbalance in the thrust produced by the engines, which can lead to a shift in the center of gravity. Pilots must carefully monitor the fuel distribution and adjust the cargo placement to ensure the center of gravity remains within safe limits.