Final answer:
Two possible ways of returning static pressure to the flight instruments should the primary static system fail during flight are using an alternate static source or utilizing the pitot-static system.
Step-by-step explanation:
When the primary static system fails during flight, there are two possible ways to return static pressure to the flight instruments. The first method is by using an alternate static source. This is a backup system that provides a separate source of outside air pressure to the instruments.
Pilots can select the alternate static source by adjusting a control in the cockpit. This ensures that the instruments continue to receive accurate static pressure even if the primary system fails.
The second method is by using the pitot-static system. This system is made up of two components: the pitot tube and the static port. The pitot tube measures the impact pressure of the airflow, while the static port measures the static pressure. In normal operations, the pitot tube and static port are connected to the flight instruments.
However, if the primary static system fails, pilots can switch to using the pitot-static system to measure static pressure and provide accurate readings to the flight instruments.