然而，如果飞行员持有的仪器等级在其必须持有的基本的飞行员执照等级之上，那么飞行员只能选择仪表飞行规则。

However, a pilot can only choose to fly IFR if they possess an instrument rating which is above and beyond the basic pilot's license that must also be held.

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E 级和 A 级空域的区别在于，在 A 级空域，所有操作都需遵照仪表飞行规则，飞行员必须要有仪表等级，也就是说，要有操作航空仪表方面的技术和执照。

The difference between Class E and A airspace is that in Class A, all operations are IFR, and pilots must be instrument-rated, that is, skilled and licensed in aircraft instrumentation.

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在晴天，在管制空域内的飞行员可以选择目视飞行规则或者仪表飞行规则的飞行计划，而且联邦航空局的条例是以这样一种方式设计的：在同一空域同时适用目视飞行规则和仪表飞行规则的操作。

On a clear day, a pilot in controlled airspace can choose a VFR or IFR flight plan, and the FAA regulations were devised in a way which accommodates both VFR and IFR operations in the same airspace.

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