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 aircraftinstrumentation.
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。
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For example, one organization may aspire to be the foremost manufacturer of aircraftinstrumentation in North America, while another may want to become a leading global drug distributor.
NACTS is a computerized aircraft, threat and target tracking system that is the "great-grandson" of the air Combat Maneuvering Instrumentation system, or ACMI.