Airlines Prepare for Cellphone Calling
Service Could Begin Next Year,
But Safety Remains an Issue;
Fliers Sneaking Calls Now
With technology and regulators moving rapidly, passengers could be making and receiving cellphone calls aboard airline flights next year. But a new study raises questions over whether that will be safe for airplanes.
The study arrives less than two months before crucial government decisions about inflight wireless communications are set to be made. On May 10, the Federal Communications Commission will auction radio spectrum that will allow telecommunications companies to operate wireless Internet and cellphone services for air travel. Already, several companies, including Verizon Communications Inc., AirCell, a closely held Colorado company, and AeroMobile, a joint venture of ARINC Inc. and Telenor ASA, are lining up to bid. The FAA recently approved a Verizon Wi-Fi system that lets laptops connect to the Internet from airplanes. (If Verizon wins spectrum at the May 10 auction, the company says the system could be up and running in 2007.) Some companies are also unveiling new technology they say will make inflight calling less disruptive and safer.
WALL STREET JOURNAL VIDEO
OnAir CEO George Cooper discusses his company's technology to put cell phones on airplanes.The problem with using cellphones on airplanes is that the devices can interfere with Global Positioning Satellite systems, researchers say. These systems are increasingly being used on commercial airplanes for navigation. Interference could cause an airplane to lose the GPS signal or even make a flight veer off course. Currently, federal rules prohibit the use of personal electronic devices onboard airplanes unless airlines can prove they are safe to operate.
In the new study, researchers at Carnegie Mellon University rode 37 passenger flights on three airlines with a device that measured radio-frequency emissions from personal electronic devices, like cellphones, BlackBerries and laptop computers. The study found emissions from cellphones that could interfere with GPS systems. It also revealed that some fliers are already making phone calls in defiance of an industrywide ban: Indeed, one to four cell calls were surreptitiously made on each flight studied.
Inflight cellular calls cause other problems, too. Since calling from high up in the air can tie up a big chunk of capacity, wireless users on the ground can be blocked from service. The FCC had banned cellphone use on planes because of this problem.
But now communications companies are unrolling new technology to address that issue. Some companies are preparing to equip airplanes with "pico cell" cellular antennas that will allow as many as 100 cellphones at a time to work without disrupting cell service on the ground. Since pico cells are installed on airplanes are thereby close to the cellphones of passengers, the phones operate at low power and won't produce interference with instruments, companies say.
Because of the pico-cell technology, which has been successfully demonstrated with calls to and from an American Airlines flight and Boeing's recent long-distance record-setting 777 trip, the FCC has dropped its objection to using cellphones on airplanes.
Now the Federal Aviation Administration must make its own decision. The agency has deputized a nonprofit advisory group called the RTCA Inc. to study the use of personal electronic devices aboard airplanes and to recommend policy, and the RTCA expects to issue a final report in December. The report will likely outline specific procedures for companies and airlines to prove that devices are safe to use, said Dave Carson, co-chair of the RTCA committee and a Boeing Co. official.
Both the Wi-Fi network and the cell service will use radio spectrum that the FCC will auction on May 10 for air-to-ground communications. The spectrum had been reserved for telephones installed on airplanes. But since those expensive, static-filled phones never took off, the FCC decided to reallocate it. Two licenses will be awarded, FCC spokeswoman Chelsea Fallon said.
But the researchers at Carnegie Mellon in Pittsburgh say they believe more study is needed before allowing inflight cellphone calls. The researchers found that even though cellphones and laptops communicate in radio bands that are separate from those used by GPS instruments, emissions were still found in the GPS spectrum. That is because emissions from several cellphones can mix together and migrate to different frequencies, a phenomenon that is called "intermodulation."
"There is a clear and present danger: cellphones can render GPS instruments useless for landings," the authors said in an article published in IEEE Spectrum. Carnegie Mellon's research was funded by the FAA.
Mr. Carson said the RTCA is looking at intermodulation and the Carnegie Mellon results. The university research "does lend some empirical support to what we knew from the beginning," he said. The RTCA has also found evidence of possible GPS receiver interference. But the committee also believes technical dangers can be overcome, he said.
One certainty: Phone use, like use of computers and other electronic devices, will only be allowed when planes are above 10,000 feet, and will be prohibited during takeoff and landing.
Sometime within the next year, airlines will likely being training flight attendants on how to instruct passengers on proper seat chatter procedures and etiquette.
With the background noise of an airplane in one ear, users tend to talk loudly into a cellphone. But yelling only makes the transmission worse (and neighbors angry), experts say, and phones don't pick up loud voices clearly. (Headphones may help.)
Do travelers really want to gab inflight? Of 8,000 comments to the FCC when it proposed dropping its ban, only two or three were in favor. The rest, except for the 50 or so technical reports, were from travelers vociferously opposed, arguing that airplanes should be a refuge from calls and emails. Flight attendant unions are also opposed, fearing obnoxious phone habits could lead to air-rage incidents.
If cellphones are allowed on airplanes, Granger Morgan, head of Carnegie Mellon's department of engineering and public policy, would like to see one other change: Flight-data recorders to track electronic emissions should be modified so that crash investigators can document a problem if trouble develops.
空中手机通话遭质疑
随著科技进步和监管部门加快审批，明年起乘客或许就能在飞机上用手机拨打和接听电话了。但一项新的研究对这么做是否会干扰飞行提出了质疑。
此时距离美国监管部门就飞行中无线通讯做出重要决定已不足两个月。今年5月10日，美国联邦通讯委员会(Federal Communications Commission, 简称FCC)将拍卖无线电频谱，允许电信公司为航空旅行提供无线互联网和手机服务。有多家公司已经准备参加拍卖，其中包括Verizon Communications Inc.、少数人持股公司AirCell以及ARINC Inc.和Telenor ASA的合资企业AeroMobile。美国航空管理局(FAA)最近批准了Verizon的一种Wi-Fi系统，该系统可使笔记本电脑在飞机上接入互联网。（Verizon表示，如果在5月10日的拍卖中赢得频谱，则将著手准备该系统，并在2007年投入运行。）一些公司也在竞相推出新技术，称这些技术将使飞行中通讯更加安全，飞机飞行不容易受到干扰。
研究人员称，在飞机上使用手机的问题是它们可能会干扰全球定位系统(GPS)。目前商用飞机越来越普遍地使用GPS帮助导航。干扰可能会导致飞机失去GPS信号，甚至使飞机偏离航线。目前，联邦政府规定禁止在飞机上使用个人电子设备，除非航空公司能够证明不会对飞行产生影响。
在这项新的研究中，卡内基梅隆大学(Carnegie Mellon University)的研究人员乘坐了3家航空公司的37个航班，他们随身携带了能够测量手机、BlackBerry和笔记本电脑发射的无线电频率的设备。这项研究发现，手机发射的频率能够干扰GPS系统。研究中还发现，一些乘客违反了禁止手机通话的行业禁令：在每个航班上都发现了1-4起暗中拨打手机的情况。
飞行过程中用手机通话还会带来其它问题。由于在高空中通话会占用大量网络流量，地面的无线用户可能会无法使用此项服务。出于这个原因，FCC一直禁止在飞机上使用手机。
但现在通讯公司正在开发新技术，以解决这个问题。一些公司准备给飞机装上微微蜂窝(pico cell)手机天线，允许至多100部手机同时通话，而不干扰地面的手机服务。这些公司表示，由于微微蜂窝安装在飞机上靠近乘客的位置，手机的功率很低，这样就不会对飞机设备产生干扰。
由于微微蜂窝技术已经在美利坚航空公司(American Airlines)的航班和波音(Boeing)777飞机的长途航行中成功通过了测试，FCC已放弃了对在飞机上使用手机的反对态度。
现在FAA必须对此做出自己的决定了。该机构已经委托非营利咨询机构RTCA Inc.研究在飞机上使用个人电子设备的问题，并提出建议，RTCA预计将在12月份发布最终报告。RTCA的联席主席、波音公司的管理人员戴夫?卡森(Dave Carson)说，这份报告可能为通讯公司和航空公司列出如何证明使用这些设备是安全的具体程序。
Wi-Fi网络和手机服务都将使用FCC在5月10日拍卖的空中与地面通讯的无线电频谱。这些频谱曾为在飞机上安装的电话所保留。但由于这些费用畸高的电话使用频率并不高，FCC决定重新分配这些频谱。FCC的发言人切尔西?法伦(Chelsea Fallon)说，将发放两个牌照。
但卡内基梅隆大学的研究人员表示，他们认为允许在空中使用手机前需要进行进一步的研究。他们发现，尽管手机和笔记本电脑的无线电波段同GPS仪器使用的波段不同，但GPS频谱中仍发现了个人电子设备发射的信号。这是因为几部手机的信号能够混合在一起，偏移到其他频率中，这种现象叫做“互调”。
他们在《IEEE Spectrum》上发表的文章中表示，很显然存在风险：手机能导致GPS设备在著陆时无法使用。卡内基梅隆大学的研究是由FAA资助的。
RTCA的联席主席卡森说，RTCA正在研究互调和卡内基梅隆大学得出的结论。他说，RTCA也发现了可能干扰GPS接收器的证据。但该委员会认为技术上的危险能够得到解决。
可以确定的一点是：手机和电脑等电子设备一样，只能够在飞机高于10,000英尺以上时使用，禁止在飞机起降过程中使用。
从明年某个时间开始，航空公司可能就将培训乘务人员如何指导乘客的座位上打电话及礼仪。
由于飞机产生的背景噪音，用户可能对著手机大声讲话。但专家称，大呼小叫只会使传输效果更差，手机无法清晰分辨高音，而且还会令周围的人感到不快。（耳机可能会有所帮助。）
乘客真的希望在飞行过程中通话吗？在FCC提出解除禁令后收到的8,000份意见中，仅有两、三个人表示赞成。除了50份左右的技术报告外，其余都是乘客言词激烈地表示反对，称这将使飞机成为电话和电子邮件的庇护所。乘务员工会也表示反对，担心不好的通话习惯会导致飞行事故。
如果允许在飞机上使用手机，卡内基梅隆大学工程与公共政策系的主任格兰杰?摩根(Granger Morgan)希望能看到另一种变化：跟踪电子信号的航行数据记录仪应进行修改，以便事故调查人员能够在飞机坠毁后了解问题所在。
