The Challenge of Taming Air Turbulence
He had taken a few hard hits as a quarterback for the Ottawa Rough Riders of the Canadian Football League.
But when his American Airlines flight on Jan. 25 from Miami to Milan, a Boeing 767 carrying 192 passengers, blew sideways, Jordan Case thought that was it.
不过，1月25日那天，当乔登‧凯斯(Jordan Case)搭着美国航空公司(American Airlines)自迈阿密飞往米兰的班机遭遇强气流的时候，他觉得大限到了。那是一架波音767客机，机上有乘客192人。
“I’ve always been a nervous flier and you’re used to bumpy turbulence,” he said. “It happened all of a sudden, just a huge jolt. It was loud and happened twice.”
Seated in business class with his wife, Karen, Mr. Case — who owns three luxury car dealerships in Plano, Tex. — said the experience was “horrific.”
The flight, which hit severe clear air turbulence at 29,000 feet, 420 nautical miles southeast of St. John’s airport in Newfoundland, was diverted to that airport, and two passengers and three flight attendants were taken to the hospital for treatment and observation.
The couple flew on to Milan the next day, and Mr. Case has flown several times since.
Turbulence is the leading cause of injuries to passengers and crew aboard commercial aircraft, according to the Federal Aviation Administration.
根据美国联邦航空管理局(Federal Aviation Administration)的数据，乱流是导致民航乘客与空服人员受伤的主要原因。
In 2015, 21 people — 14 crew members and seven passengers — were injured by turbulence, according to the F.A.A.; in 2014, 31 people were injured, nine crew members and 22 passengers.
The worst recent year was 2010, when 76 people — 25 crew members and 51 passengers — were injured by turbulence.
There are many different kinds of turbulence, with the most problematic to predict and to avoid being clear air turbulence (which is very difficult to detect using conventional radar). Much of it is typically experienced at cruising altitude.
In the last few months, at least three commercial flights, two on American Airlines and one on Air Canada, have experienced severe turbulence that resulted in injuries to those on board. In two instances, the flights were diverted to nearby airports so the injured could receive treatment.
Aviation professionals classify turbulence from light to extreme, a form they say is very rare. The challenge of reporting turbulence, several pilots said, is that the reports themselves are subjective.
While in flight, pilots file Pilot Reports (Pireps) to alert airline dispatchers and other pilots en route of any turbulence they’ve encountered; what one pilot considers mild might feel moderate to another.
What aviation professionals know is that a global network on the ground also helps guide every flight.
“I call it the safety net,” said John Lanicci, professor of meteorology at Embry-Riddle Aeronautical University in Daytona Beach, Fla. “You have pilots en route chatting, you have the air control centers and the flight dispatchers for the airlines.” If a flight hits severe enough turbulence that injuries result, a medical professional on the ground is also consulted and a decision quickly made whether to divert, land and take the injured to the hospital.
“我把这叫做‘安全网’，”约翰‧朗尼奇(John Lanicci)说。他是佛罗里达戴通纳海滩（代托纳比奇）的安柏瑞德航空大学(Embry-Riddle Aeronautical University)的气象学教授。“你有航线上的飞行员相互通话，还有空管中心与各航空公司的班机调度员。”要是有班机遇上严重到足以伤人的乱流，地上也有医学专家可供咨询，马上决定是否该更改航线、降落、将伤患送医。
When flights like American Airlines 206, the one Mr. Case was on, are forced to divert because of turbulence-related injury, it costs airlines both financially and reputationally, said Mark Miller, senior vice president and general manager, decision support at the Weather Company, an IBM business.
IBM旗下的气象公司(Weather Company)决策支持部高级副总裁与总经理马克‧米勒(Mark Miller)认为，如果航班被迫变更航线，比如凯斯乘坐的美国航空206航班遇到的那次，此类事件会导致航空公司受到经济与名誉上的双重损失。
Mr. Miller, a meteorologist, said that turbulence can force aircraft to choose less than optimal routes that use more fuel and are less efficient, and the roughest flights can require additional aircraft checks and maintenance.
Brand perception is another issue, he added. “It’s a big problem for emerging markets if new fliers see passengers coming off in a neck brace.” And yet, Mr. Miller and Dr. Lanicci agree, some routes are simply more likely to prove bumpy, like Asia-Pacific flights. “It’s a big problem,” Mr. Miller said. If it looks like a flight is going to be rough “that perception can impact demand for air travel.”
米勒还说，品牌形象是另一个问题。 “对新兴市场来说，新客户看到有人脖子装着支架下飞机，麻烦就大了。”然而米勒与朗尼奇也承认，有些航线就是比较容易颠簸，比如亚太航线。 “这是个大问题，”米勒说。如果一段航程看起来将会颠簸不平，“这种认识就会影响飞行需求”。
The American Airlines flight that the Cases took encountered only a few seconds of turbulence, said a spokesman for the airline, Ross Feinstein, and the plane was not damaged.
Aviation crews admit that experiencing turbulence can be frightening and disorienting, even sometimes for them as well, but they emphasize that planes are designed and manufactured to weather it.
“Our airplanes are built to withstand 3.75 G load before there is any kind of damage — that’s almost four times gravity,” said Doug Alder, a spokesman for Boeing. “Some of the worst turbulence gets in the range of 2 to 2.5 G’s, well below the damage tolerance.”
“我们建造的飞机能承受最高达3.75G的冲击而不会有任何损伤，几乎是重力的四倍。”波音公司发言人道格‧阿尔德(Doug Alder)表示。 “最严重的乱流的冲击力一般在2到2.5G之间，远在飞机的耐损限度之下。”
“Flights are diverted because passengers have been injured by turbulence, not because the airplane has been damaged,” he said.
After events of severe turbulence, aircraft are also carefully examined for any damage to be sure they remain airworthy.
A study of upper-level turbulence, examining two million pilot reports between January 1994 and December 2005, showed a spike in reports between 1997 and 1998, Dr. Lanicci said, which the study’s authors suggested could be attributed to El Niño.
This year’s El Niño has affected weather patterns worldwide as well.
“It’s an interesting question,” Dr. Lanicci said when asked if El Niño is currently causing more frequent or more severe turbulence. “Inconclusive,” said David Hosansky, a spokesman for the National Center for Atmospheric Research, a federally funded research and development center.
“这是个有趣的问题。”当被问及厄尔尼诺现象是否正在造成更为频繁和严重的乱流，朗尼奇如是说。美国国家大气研究中心(National Center for Atmospheric Research)发言人大卫‧侯山斯基(David Hosansky)则表示：“尚无定论。”该单位为美国联邦政府资助的研究发展中心。
As 2015 was also the hottest year so far on record, is there a link between severe turbulence and climate change?
While a paper published in 2013 in the journal Nature Climate Change said there was a causal link between the two, Dr. Lanicci said that there are too many complex factors to make this connection directly. “Every year is going to be different, so can we also go back to every turbulence report and correlate it to climate change?” he said. “There are too many things that could contribute to that.”
虽然《自然气候变化》(Nature Climate Change)在2013年刊载的一份研究宣称两者间有因果关系，不过朗尼奇表示，还有太多复杂因素，很难确定乱流与气候变化的直接关系。 “每一年都会不一样，难道我们能去追溯每一次乱流报告，然后找出它和气候变化的关联吗？”他说。 “有太多因素会导致乱流。”
Passengers who fly a great deal can become blasé and forget to stay firmly buckled in, or start to ignore warnings when anticipated turbulence doesn’t happen, airline crews said.
It’s a risk to avoid.
The problem with light turbulence is that it can turn into severe turbulence in a matter of seconds. Those not securely strapped into their seats can, and have, flown into galley carts, arm rests or the ceiling, breaking hips, arms and noses and risking concussion.
In a highly competitive industry, flight crews must balance offering service with keeping passengers and crew safe. Once an announcement has been made instructing crew to remain seated — marking a period of anticipated intense turbulence — anyone not wearing a seatbelt is at risk.
Each airline has dozens of meteorologists on staff helping to plan and guide their flights to avoid turbulence whenever possible, and pilots have access to a wealth of real-time information.
More than 700 aircraft, such as the 737, 757, 767, 777 and Airbus A319 and 321, are using the Weather Company’s four-year-old software program, Total Turbulence, which collects and shares data with pilots using the system.
“The challenge of turbulence is that there’s no one answer to the problem,” Mr. Miller said.