What requirement must aircrew be familiar with regarding fuel?

Familiarity with fuel sampling procedures is essential for aircrew because these procedures ensure the safety and performance of the aircraft. Fuel sampling involves taking samples of aviation fuel to check for contamination or quality issues that could affect engine performance or operational safety. This practice helps identify the presence of water, sediment, or microbial growth in the fuel, which can lead to engine malfunctions or diminished efficiency. Understanding these procedures allows aircrew to act proactively and mitigate risks associated with fuel quality, thus ensuring the aircraft is safe for operation.

The other options, while relevant in the context of aircraft operations and maintenance, do not specifically relate to the immediate requirement for aircrew to manage fuel-related safety and performance concerns. Understanding fuel sampling is fundamentally critical as it directly impacts the safety and reliability of flight operations.