Transatlantic airplanes are flying at the ‘speed of sound’ right now. Here’s why
Savior of many a cramped pair of legs, the jet stream is well known for lopping roughly an hour off long haul west-to-east flights.
But it’s working especially hard for travelers in economy class right now, with the jet stream over the Atlantic so strong that flights heading from the US to Europe are reaching speeds equivalent to that of sound.
Sound travels at about 761 mph or 1,100 feet per second in “sea level standard conditions,” according to NASA – a little over 661 knots.
In the past 24 hours, passenger aircraft traveling east from the US across the Atlantic have reached up to 778 mph. That’s a little over 200 miles per hour faster than normal cruising speeds.
But if you’re thinking these flight times are a match for the much-missed Concorde, whose sonic booms used to mark it breaking the sound barrier, it’s time to think again. There’s a difference between ground speed and speed in the air (indicated air speed, essentially the speed of the plane in relation to the air around it). These passenger flights, however speedy, didn’t break the sound barrier.
But they did slash flight times. Emirates flight 222 from Dallas to Dubai arrived 57 minutes early on November 1, having reached a top speed of 675 knots, or 777 mph, off the coast of Newfoundland, according to flight tracking site Flightaware.
American Airlines flight 106 from JFK to Heathrow arrived 54 minutes early on Wednesday morning, with a flight time of just six hours and seven minutes. It reached a top speed of 778 mph, or 676 knots, also just past Newfoundland.
Meanwhile Delta flight 186 raced from Los Angeles to London with top speeds of 760mph, arriving half an hour early on November 1 at 1.08 p.m.
A KLM cargo plane which took off nearly four hours late on November 1 was due to arrive just under two hours late, traveling from Miami to Amsterdam.
The jet stream explained
The jet stream is a “core of strong winds around five to seven miles above the Earth’s surface, blowing from west to east,” as the UK’s Met Office describes it.
It’s the reason why eastbound flights tend to be shorter than westbound ones – with long haul flights racking up time differences of an hour or more, depending on the direction of travel.
Seven miles above the planet’s surface is equivalent to around 37,000 feet – which means that aircraft at cruising altitude slip easily into the jet stream.
And it’s the rapidly cooling weather stateside this week (now heading to Europe in the form of Storm Ciaran) that’s responsible for the speeding up of the winds, according to CNN meteorologist Sara Tonks.
“This week’s burst of cold air in the United States has upped the difference in temperature between the United States (cold!) and the Atlantic Ocean (warm!),” she says.
“This increase in the temperature gradient is amplifying the speed of the jet stream, which is driven by temperature differences.
“The jet stream is expected to help strengthen Storm Ciaran, a low pressure system and potential bomb cyclone that is expected to arrive in Europe tonight [Wednesday].”
CNN meteorologist Derek Van Dam added: “Remember, ground speed is how fast an airplane is traveling, relative to a fixed point on the ground versus airspeed which is the speed of an aircraft relative to the air through which it is moving. Either way, these planes are saving time and money.”
However fast the flights this week, they have a little way to make up for some record-breaking flights pre-pandemic.
In February 2019, a Virgin Atlantic plane flew at 801mph from Los Angeles to London, reaching its top speed over Pennsylvania thanks to a 200mph jet stream – although it slowed down to a mere 710mph once it hit the ocean. The aircraft – a Boeing 787 Dreamliner – usually has a cruising speed of around 560mph. Virgin founder Richard Branson described it as flying “faster than any other commercial non-supersonic plane in history.”
Its record was broken the following year by a British Airways Boeing 747. The BA jumbo clocked in at 825mph on a New York to London flight, slashing the journey time from around seven hours to just under five. On that same day, another Virgin Atlantic plane made the same route with a journey time of just two minutes more.
急流是许多腿脚不便人士的救星，众所周知，它可以将西向东的长途航班飞行时间缩短约一小时。
但目前急流对经济舱的旅客来说尤其困难，大西洋上空的急流非常强劲，从美国飞往欧洲的航班速度已达到与音速相当。
据美国宇航局称，在“海平面标准条件下”，声音传播速度约为每小时 761 英里或每秒 1,100 英尺，略高于 661 节。
在过去 24 小时内，从美国向东飞越大西洋的客机时速已达到每小时 778 英里。这比正常巡航速度快每小时 200 多英里。
但如果你认为这些飞行时间与备受怀念的协和式飞机相媲美，协和式飞机曾以音爆标志着其突破音障，那么是时候重新考虑了。 地面速度和空中速度（指示空速，本质上是飞机相对于周围空气的速度）是有区别的。这些客运航班无论速度多快，都没有突破音障。
但它们确实缩短了飞行时间。根据航班跟踪网站 Flightaware 的数据，阿联酋航空 222 航班从达拉斯飞往迪拜，于 11 月 1 日提前 57 分钟抵达纽芬兰海岸，最高时速达到 675 节，即 777 英里/小时。

这架飞机的最高时速达到了 777 英里/小时或 675 节。
图片来源：Flightradar24
美国航空 106 航班从肯尼迪机场飞往希思罗机场，于周三早上提前 54 分钟抵达，飞行时间仅为 6 小时 7 分钟。它的最高时速达到 778 英里/小时，即 676 节，同样刚好经过纽芬兰。
与此同时，达美航空 186 号航班以最高时速 760 英里/小时的速度从洛杉矶飞往伦敦，于 11 月 1 日下午 1 点 08 分提前半小时抵达。
一架荷兰皇家航空公司的货机于 11 月 1 日晚点近四个小时起飞，原定于晚点近两个小时抵达，从迈阿密飞往阿姆斯特丹。
急流解释
正如英国气象局所描述的那样，急流是“地球表面五到七英里上方从西向东吹来的强风核心”。
这就是为什么向东飞行的航班往往比向西飞行的航班短的原因——长途航班的时差会达到一个小时或更长时间，具体取决于旅行方向。
地球表面以上七英里相当于约 37,000 英尺——这意味着巡航高度的飞机很容易滑入急流。
据 CNN 气象学家 Sara Tonks 称，本周美国本土的天气迅速变冷（目前正以风暴 Ciaran 的形式向欧洲移动），导致风力增强。
世界上飞行时间最长的飞机在空中飞行了两个多月
“本周美国爆发的冷空气加大了美国（冷！）和大西洋（暖！）之间的温差，”她说。
“温度梯度的增加放大了急流的速度，而急流是由温差驱动的。
“预计急流将有助于加强风暴 Ciaran，这是一个低压系统和潜在的炸弹气旋，预计将于今晚 [星期三] 抵达欧洲。”
CNN 气象学家 Derek Van Dam 补充道：“请记住，地速是飞机相对于地面固定点的飞行速度，而空速是飞机相对于其所穿过的空气的速度。 无论如何，这些飞机都节省了时间和金钱。”
急流使飞机的速度比平均速度快 200 英里/小时。
无论本周的航班有多快，它们都在某种程度上弥补了疫情前一些破纪录的航班。
2019 年 2 月，一架维珍航空的飞机以 801 英里/小时的速度从洛杉矶飞往伦敦，在 200 英里/小时的急流作用下，在宾夕法尼亚州上空达到了最高速度——尽管它在撞上海洋后减速到仅 710 英里/小时。这架飞机是波音 787 梦想飞机，通常巡航速度约为 560 英里/小时。维珍创始人理查德·布兰森将其描述为“比历史上任何其他商用非超音速飞机都快”。
次年，英国航空的一架波音 747 打破了这一纪录。这架英国航空的巨型客机在从纽约飞往伦敦的航班上时速达到 825 英里，将飞行时间从大约七个小时缩短到将近五个小时。同一天，另一架维珍航空的飞机也飞过同样的航线，飞行时间仅比当时多了两分钟。
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