对于以目视飞行规则飞行的飞机，是飞机将到达机场上空的估计时间。

For VFR flights, the time at which it is estimated that the aircraft will arrive over the aerodrome.

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受管制空域，一个范围明确的空域。在该空域内，仪表飞行规则飞行和目视飞行规则飞行有空中交通管制服务。

CONTROLLED airspace, an airspace of defined dimensions within which air traffic control service is provided to IFR flights and to VFR flights in accordance with the airspace classification.

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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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