How many flapper valves are installed in each wing tank?

The correct information regarding the number of flapper valves installed in each wing tank is nine. This design helps to maintain fuel management and stability within the wings during flight. Flapper valves are critical for ensuring that fuel can move effectively and that the tanks can operate correctly under varied airflow and pressure conditions.

Having nine flapper valves serves multiple purposes: they help prevent fuel from sloshing excessively during maneuvers, enhance the efficiency of fuel transfer between tanks, and contribute to the overall safety and performance of the aircraft. Proper understanding of flapper valve functionality is crucial for pilots and maintenance crews, as it directly impacts fuel management strategies and aircraft handling characteristics.

In contrast, other options such as six, ten, and twelve do not reflect the actual design and engineering specifications of the fuel system in the aircraft, thereby leading to misunderstandings regarding the aircraft's operational capabilities. Therefore, knowing that there are nine flapper valves in each wing tank is essential for aircraft systems comprehension.