Which option correctly states the determination rule for the overwater minimum engine oil quantity?

• A. The minimum is always 60% (12 quarts).
• B. The minimum is always the 7 quarts + 1 quart per total flight hour.
• C. The minimum is the lesser of 60% (12 quarts) and the formula.
• D. The minimum is the greater of 60% (12 quarts) and the 7 quarts + 1 quart per total flight hour formula.

Answer: (D)

The rule tests how to set the overwater minimum engine oil quantity by balancing a fixed baseline against a duration-based requirement. The fixed baseline is 60% of capacity, which equals 12 quarts. The duration-based rule starts at 7 quarts and adds 1 quart for every total flight hour. To determine the minimum, you take the greater of these two values. This ensures you have at least 12 quarts for shorter flights, while letting the requirement rise for longer missions to maintain proper lubrication. For example, a 4-hour flight needs 7 + 4 = 11 quarts, so you carry 12 quarts. A 6-hour flight needs 7 + 6 = 13 quarts, so you carry 13 quarts. Relying only on the fixed 12 quarts would under-protect longer flights, and relying only on the formula would under-protect shorter ones. Therefore, the correct approach is to use the greater of the fixed 60% (12 quarts) and the 7 quarts plus 1 quart per total flight hour formula.