段落A

An accident that occurred in the skies over the Grand Canyon in 1956 resulted in the establishment of the Federal Aviation Administration (FAA) to regulate and oversee the operation of aircraft in the skies over the United States, which were becoming quite congested. The resulting structure of air traffic control has greatly increased the safety of flight in the United States, and similar air traffic control procedures are also in place over much of the rest of the world.

段落A

1956年，大峡谷上空的一起事故导致了联邦航空管理局（Federal Aviation Administration，简称FAA）的成立，以监管和管理美国上空飞行器的运营，因为这些空域正在变得非常拥挤。随后建立的空中交通管制系统极大地提高了美国飞行的安全性，类似的空中交通管制程序也在世界其他地区得到应用。

段落B

Rudimentary air traffic control (ATC) existed well before the Grand Canyon disaster. As early as the 1920s, the earliest air traffic controllers manually guided aircraft in the vicinity of the airports, using lights and flags, while beacons and flashing lights were placed along cross-country routes to establish the earliest airways. However, this purely visual system was useless in bad weather, and, by the 1930s, radio communication was coming into use for ATC. The first region to have something approximating today’s ATC was New York City, with other major metropolitan areas following soon after.

段落B

大峡谷灾难之前，还存在着基本的空中交通管制（ATC）。早在1920年代，最早的空中交通管制员就通过使用灯光和旗帜，在机场附近手动引导飞机，同时在跨国航线上设置灯塔和闪光灯来建立最早的航线。然而，纯视觉系统在恶劣天气下毫无用处，到了1930年代，无线电通信开始被用于空中交通管制。第一个拥有类似于今天ATC的地区是纽约市，其他主要都会区很快也相继建立了类似的系统。

段落C

In the 1940s, ATC centres could and did take advantage of the newly developed radar and improved radio communication brought about by the Second World War, but the system remained rudimentary. It was only after the creation of the FAA that full-scale regulation of America’s airspace took place, and this was fortuitous, for the advent of the jet engine suddenly resulted in a large number of very fast planes, reducing pilots’ margin of error and practically demanding some set of rules to keep everyone well separated and operating safely in the air.

段落C

在二战中，ATC中心能够并且确实利用新开发的雷达和改进的无线电通信，但系统仍然很基础。直到FAA的创建后，美国空域的全面监管才开始进行，这是幸运的，因为喷气发动机的出现突然导致了大量飞行速度非常快的飞机，减少了飞行员的错误容许度，实际上需要一套规则来保持每个人在空中保持足够的间隔和安全运行。

段落D

Many people think that ATC consists of a row of controllers sitting in front of their radar screens at the nation’s airports, telling arriving and departing traffic what to do. This is a very incomplete part of the picture. The FAA realised that the airspace over the United States would at any time have many different kinds of planes, flying for many different purposes, in a variety of weather conditions, and the same kind of structure was needed to accommodate all of them.

段落D

许多人认为ATC由一排控制员坐在国家机场的雷达屏幕前，告诉到来和离开的飞机该做什么。这只是这个画面的很小一部分。FAA意识到，美国上空将同时存在许多不同种类的飞机，以及各种目的地的飞机，处于各种天气条件下飞行，所以需要相应的结构来适应它们。

段落E

To meet this challenge, the following elements were put into effect. First, ATC extends over virtually the entire United States. In general, from 365m above the ground and higher, the entire country is blanketed by controlled airspace. In certain areas, mainly near airports, controlled airspace extends down to 215m above the ground, and, in the immediate vicinity of an airport, all the way down to the surface. Controlled airspace is that airspace in which FAA regulations apply. Elsewhere, in uncontrolled airspace, pilots are bound by fewer regulations. In this way, the recreational pilot who simply wishes to go flying for a while without all the restrictions imposed by the FAA has only to stay in uncontrolled airspace, below 365m, while the pilot who does want the protection afforded by ATC can easily enter the controlled airspace.

段落E

为了应对这一挑战，采取了如下措施。首先，空中交通管制遍布整个美国。一般来说，从离地面365米以上的高度开始，整个国家都是受控空域。在某些区域，主要是机场附近，受控空域延伸到离地面215米，并且在机场的附近一直延伸到地面。受控空域是指适用FAA规定的空域。在其他地区，飞行员需要遵守较少的规定来驾驶在无控制空域中飞行。这样，只想简单地进行飞行而不受FAA施加的所有限制的休闲飞行员，只需停留在离地面365米以下的无控制空域内，而想要得到ATC保护的飞行员可以轻松进入受控空域。

段落F

The FAA then recognised two types of operating environments. In good meteorological conditions, flying would be permitted under Visual Flight Rules (VFR), which suggests a strong reliance on visual cues to maintain an acceptable level of safety. Poor visibility necessitated a set of Instrumental Flight Rules (IFR), under which the pilot relied on altitude and navigational information provided by the plane’s instrument panel to fly safely. 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. 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.

段落F

然后，FAA认识到存在两种不同的操作环境。在良好的气象条件下，允许进行目视飞行规则（Visual Flight Rules，简称VFR）飞行，这意味着强烈依赖视觉线索来保持安全水平。低能见度则需要一套仪表飞行规则（Instrumental Flight Rules，简称IFR），在这种规则下，飞行员依靠飞机仪表板提供的高度和导航信息来安全飞行。在晴天时，控制空域中的飞行员可以选择VFR或IFR飞行计划，而FAA的规定被设计成同时适用于VFR和IFR飞行操作。然而，飞行员只有在持有超过基本飞行员执照的仪表评级时才能选择进行IFR飞行。

段落G

Controlled airspace is divided into several different types, designated by letters of the alphabet. Uncontrolled airspace is designated Class F, while controlled airspace below 5, 490m above sea level and not in the vicinity of an airport is Class E. All airspace above 5, 490m is designated Class A. The reason for the division of Class E and Class A airspace stems from the type of planes operating in them. Generally, Class E airspace is where one finds general aviation aircraft (few of which can climb above 5, 490m anyway), and commercial turboprop aircraft. Above 5, 490m is the realm of the heavy jets, since jet engines operate more efficiently at higher altitudes. 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. This is because ATC control of the entire space is essential. Three other types of airspace, Classes D, C and B, govern the vicinity of airports. These correspond roughly to small municipal, medium-sized metropolitan and major metropolitan airports respectively, and encompass an increasingly rigorous set of regulations. For example, all a VFR pilot has to do to enter Class C airspace is establish two-way radio contact with ATC. No explicit permission from ATC to enter is needed, although the pilot must continue to obey all regulations governing VFR flight. To enter Class B airspace, such as on approach to a major metropolitan airport, an explicit ATC clearance is required. The private pilot who cruises without permission into this airspace risks losing their license.

段落G

受控空域被划分为几种不同类型，由字母表示。无控制空域被指定为F类空域，而海平面以上至5490米处且不靠近机场的受控空域被划定为E类空域。所有高于5490米的空域被指定为A类空域。将E类和A类空域区分开的原因在于它们中操作的飞机类型。一般而言，E类空域是通用航空飞机（其中很少有飞机能够爬升到5490米以上），以及商业涡轮螺旋桨飞机的领域。高于5490米的空域则属于大型喷气式飞机，因为喷气发动机在较高高度上运行更高效。E类和A类空域的区别在于A类空域中的所有操作都是IFR，飞行员必须具备仪表评级，即在飞机仪表方面熟练并取得许可。这是因为ATC对整个空域的控制是必要的。还有三种其他类型的空域，D类、C类和B类，用来管理机场附近的空域。它们大致对应于小型市政机场、中型都会机场和大型都会机场，并包含越来越严格的规定。例如，要进入C类空域，只需与ATC建立双向无线电联系，不需要ATC的明确许可即可进入，尽管飞行员必须继续遵守所有关于VFR飞行的规定。要进入B类空域，例如在接近大型都会机场时，需要明确的ATC许可。未经许可而进入这种空域的私人飞行员可能会失去执照。