Aviation – The Future of Flight

航空——飞行的未来

Despite appearances, aircraft have changed a lot – and will soon change more, writes Geoffrey Carr.

本专题作者杰弗里·卡尔认为，尽管外观还是老样子，飞机已经发生了很大的变化，而且很快还会改变更多。

On March 10th a Boeing 737 MAX, the latest version of that firm’s bestselling narrow-bodied airliner, fell from the sky in Ethiopia. All 157 souls on board were lost. This followed the crash off the coast of Java, less than five months earlier, of another 737 MAX. The death toll then was 189. The immediate cause in both cases seems to have been a faulty sensor feeding false data to an avionic flight-management system that had, in turn, had new software which pilots had not been briefed about. The flight-management system insisted on overriding the actions of the pilots, who did not know how to respond. This precipitated a stall rather than, as intended, preventing one.

今年3月10日，一架波音737 MAX从埃塞俄比亚上空坠落，机上157人全部丧生。这距离另一架737 MAX在爪哇海岸坠毁还不到五个月，那一次共189人遇难。737 MAX是波音最畅销的窄体客机737系列的最新机型。两起事故的直接原因似乎都是有缺陷的传感器向航空电子飞行管理系统输送了错误的数据，而这个系统里又装有未向飞行员介绍过的新软件。该系统坚持否决了飞行员的操作决策，而飞行员不知道该怎么办了。原本为防止飞机失速而设计的程序反而引向了失速。

These two tragedies illuminate the tension between conservatism and innovation that lies at the heart of civil-aviation technology. As a character in “The Leopard”, a novel about the revolutionary events of Italy’s unification in the 19th century, declares: “If we want things to remain as they are, everything needs to change.” Attempts by the industry to follow that advice seem to have been what ultimately caused these crashes.

两次悲剧凸显了守旧与创新在民用航空技术核心地带的角力。就像记述19世纪意大利统一过程中的革命事件的小说《豹》（The Leopard）中的一个人物所宣称的：“如果我们希望事物保持原样，那么一切都需要改变。”航空业努力听从这一忠告，结果却似乎是从根本上导致了这些坠机事故。

The 737 goes back many years. It was conceived in the 1960s, when engines were smaller and passengers generally embarked and disembarked using staircases wheeled in for the purpose rather than airbridges connected directly to a terminal building. Small engines allowed, and staircases encouraged, a design that kept the fuselage close to the ground.

737系列诞生于很多年前。它是在上世纪60年代构想出来的，当时发动机还比较小，乘客一般会通过推到飞机旁的舷梯上下飞机，而非使用直接连接到候机楼的登机桥。发动机小让机身更贴近地面，而使用舷梯更促成了这样的设计。

By the time the 737 MAX was being planned, this had changed. Modern turbofan engines with wide air intakes required, and airbridges permitted, alterations to the airframe that also altered its handling characteristics (its trim, to use the jargon). To keep things as they were, and avoid pilots having to recertify to fly the new version, its avionic software was tweaked to make the new plane’s trim feel, to a pilot, like the old plane’s. That would have been fine as long as the sensors feeding information to those avionics worked properly and the pilots themselves knew what was going on. But they did not.

到规划737 MAX机型时，情况已经改变。使用宽进气口的现代涡轮风扇发动机要求飞机结构做出改变，而使用登机桥上下机也让这种改变成为可能。机体的改动继而改变了飞机的操纵特性（用行话说就是“配平”）。为让一切保持原样，并让飞行员无需重新认证就能驾驶新机型，波音对航空电子软件做了些调整，让飞行员在操纵新飞机时感觉和开老机型时一样。假如向这些电子软件传输信息的传感器正常运作，并且飞行员们又清楚知道在发生什么，那么这么干并没有什么问题。可惜实际上并非如此。

The case of the 737 MAX is an extreme example of conservatism at work in aircraft design. But retaining the familiar is a recurring theme. A Boeing 707, the plane that ushered in mass intercontinental air transport in the 1950s, appears to the untutored eye much like the current offerings of Boeing and Airbus, the world’s principal makers of airliners. Both old and new are portholed tubes that have two swept-back wings sticking out of their sides about halfway along. They have three stabiliser fins – two horizontal and one vertical – at the stern. Pods containing their engines hang on pylons from their wings.

737 MAX的案例是“守旧”影响飞机设计的一个极端例子。但是，保留人们已经熟悉的东西是一个反复出现的主题。上世纪50年代，波音707的出现开启了大规模洲际航空的时代。但在外行人眼中，这款飞机和波音、空客这两大飞机制造商现在的产品无甚差别。新老飞机一样都是带舷窗的大管子；机身大约一半处有两个后掠机翼向两侧伸出；机尾装有三个稳定翼——两个水平，一个垂直；装有发动机的吊舱挂在机翼下方的支架上。

 

Festina lente

欲速则不达

Attempts to change this arrangement have been proposed – most notably Boeing’s delta-winged Sonic Cruiser in the early 2000s. But apart from Concorde, a supersonic aircraft in which the delta-winged arrangement was imposed by the laws of physics, such changes have never got anywhere. Engineers know how to keep it safe, and the world’s airports have grown in synergy with it. Beneath this conservative geometry, however, airliner technology has improved enormously and is still improving. Better materials are making planes lighter and more comfortable to fly in. Better engines are making them quieter and cheaper to run. And better avionics are, despite exceptions of the sort seen so recently, making them safer .

人们已经提出过改变这种构造的尝试。最出名的是波音在本世纪初推出的三角翼“音速巡航机”（Sonic Cruiser）。但除了超音速飞机“协和号”（Concorde）因为物理定律而必须使用三角翼外，这类变化从未普及。工程师们知道如何保证安全性，而世界各地的机场也与之协同发展。然而，在几何结构大致不变的表面之下，民航技术已经大大改进，并且仍在提升。更好的材料使飞机变得更轻巧，乘坐体验更舒适。改进的发动机减少了噪音，也降低了运营成本。尽管最近出现了那种例外情形，更先进的航空电子设备让客机变得更加安全。

Those better avionics also point inexorably in one direction: to a day when most aircraft will no longer require a pilot. Airlines and their passengers and regulators may take a while to come to terms with this, so it is likely that pilots will sit in cockpits long after they are needed for anything other than the reassurance of the paying public. But armed forces are embracing a pilotless future. Surveillance and missile-carrying drones have been around for a couple of decades. The 2020s will see robot military helicopters introduced and pilotless fighter jets starting to emerge, even though these jets will, at least to begin with, be parts of squadrons that have a human leader in control. Cargo aircraft – military probably and civilian possibly – will be robotized as well.

那些更好的航空电子设备还毅然决然地指向一个方向：大多数飞机都不再需要飞行员的那一天。航空公司、乘客以及监管部门可能尚需要一些时间才能接受这种变化，所以在很长一段时间里，飞行员应该还会继续坐在驾驶舱内，即便他们的存在只是为了让花钱坐飞机的民众感到安心。但军队已经在拥抱一个无人驾驶的未来。用于侦查和运载导弹的无人机已经存在了二三十年。到2020年代，我们将看到机器人军用直升机和无人驾驶战机开始出现，它们至少会开始成为由人类领导的飞行中队的成员。货运飞机也会改用机器人驾驶员——军用货机在这方面的可能性比民用的更大。

New technology is also extending the concept of civil aviation. The idea of supersonic transport (SST) for civilians is back on the cards, 16 years after Concorde’s last flight. Three firms in America, in particular, have plausible designs for SSTs, appropriate commercial partnerships, and, they hope, sufficient money to get prototypes flying over the next few years. And another old fantasy, flying cars, seems likely to become real in the next few years, as firms both new and old rush to build electrically propelled one- and two-seater aircraft of novel design. Some will act as remotely controlled taxis. Some will be the SUVs of the sky – piloted by their owners over city traffic jams and winding country roads alike.

新技术也在扩展民用航空的概念。在协和号最后一次飞行的16年后，将超音速运输（SST）用于民航的想法再度流行。尤其有三家美国公司已经拿出了似乎合理的SST设计，建立了恰当的商业合作关系；它们希望还能拿到足够的资金，在未来几年内把原型机送上天空。而另一个古老的梦想——会飞的车——似乎很可能在未来几年里实现，因为新老企业都在竞相制造全新设计的一人座或二人座电动飞机。它们有些会充当遥控出租车，有些会成为空中SUV——由车主自己驾驶，飞越拥堵的城市和蜿蜒的乡村道路。

They all laughed at Wilbur and his brother

他们都嘲笑威尔伯和他的兄弟

In these two areas, SSTs and flying cars, change is happening that is reminiscent of the glory days of aeronautics – the half-century after 1903, the year that the Wright brothers made the first widely recognized, heavier-than-air powered flight, at Kitty Hawk, North Carolina. Flying cars especially, if they can be proved safe and manageable by air-traffic-control systems, may change transport networks almost as much as their ground-based brethren did a century ago, by being able to avoid the congestion that the multiplication of those brethren has brought.

在超音速飞机和会飞的车这两个领域，正在发生的变化让人想起航空业的辉煌岁月——1903年后的半个世纪。那一年，在北卡罗来纳州的小鹰镇（Kitty Hawk），莱特兄弟完成了第一次被世人广泛认可、用动力驱动重于空气的航空器的飞行。特别是会飞的车，如果它们被证明是安全的，且能由空中交通管制系统管理，那么它们给交通网络带来的改变或许将堪比一个世纪前开始在地上跑的车，因为它们能绕过这些地上的兄弟们迅速增殖造成的拥堵。

Conventional civil aviation is also growing fast. The number of jet airliners flying may double by 2040 as people, particularly those in Asia who do not fly now, get richer. That will bring environmental problems, for aviation is the least tractable of industries to decarbonisation in order to reduce greenhouse-gas emissions. Aviation fuel packs more energy per kilogram than batteries do. And, so far, attempts to make such fuel synthetically, rather than from petroleum, have foundered on cost. The embrace of, or resistance to, the growth of aviation may depend on whether that, too, can change.

传统民航业也在快速增长。随着人们变得更富有——尤其是亚洲那些现在还不乘飞机的人——到2040年，服役喷气式客机的数量可能会翻一番。这将带来环境问题，因为航空业是最不容易通过脱碳来减排的行业。航空燃料每公斤的能量密度要高于电池，而到目前为止用人工合成而非石油制造这种燃料的尝试已经因为成本问题而失败了。航空业的扩张是受到欢迎还是被抵制，可能也将取决于这一点能否改变。

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