What should be checked post-flight regarding the fuel system?

The post-flight check of the fuel system is crucial for ensuring the aircraft's performance and safety for future flights. One of the key elements to be examined is the oil quantity and fuel filter bypass valve. Checking the oil quantity verifies that the engine has sufficient lubrication, preventing potential damage and ensuring smooth operation.

The fuel filter bypass valve is particularly important because it ensures that the fuel system can bypass a clogged filter and continue to supply fuel to the engine if necessary. This examination can help prevent fuel starvation in flight due to obstructions in the fuel filter, which could lead to engine issues or failure.

While fuel type used, fuel pressure levels, and the number of fuel nozzles are also important aspects of the fuel system, they do not address the critical operational readiness and safety implications associated with the oil quantity and the bypass valve. Thus, the focus on the oil quantity and fuel filter bypass valve during post-flight checks helps maintain overall aircraft safety and reliability.