This is going to be a verrrry geeky entry, so fasten your seat belt for a deep dive.
A Carnegie Mellon University (CMU) study on the impact of portable electronic devices on commercial airplane electronics was widely covered in the press recently, but it was grossly misinterpreted. The story was picked up and distributed by Associated Press and run in USA Today print editions and various blogs like EnGadget. Unfortunately, it was lemmings rushing at the cliffs, since none of the reporters bothered to read anything beyond the press release — or to pick up on the researcher history .
Though I was unable to find the full text of CMU study, I did find two articles, one authored by Bill Strauss, in Issues in Science and Technology, Winter 2002 and a second co-authored by Strauss and others from CMU in IEEE Spectrum, March, 2006. To me, it looked as though both articles were based on the same data and the same study. The second article picked up the most press.
Timing, as they say, is everything. But in reality, you should blame the PR agency that wrote the headline for CMU: Carnegie Mellon Researchers Find Cell Phones Pose Greater Risk to Airplane Navigation Than Previously Believed. Turns out, that is not really what Bill Strauss said.
Here is a clip from the IEEE Spectrum article:
In one telling incident, a flight crew stated that a 30-degree navigation error was immediately corrected after a passenger turned off a DVD player and that the error reoccurred when the curious crew asked the passenger to switch the player on again. Game electronics and laptops were the culprits in other reports in which the crew verified in the same way that a particular PED caused erratic navigation indications.
Here is another quote from 3 years earlier, in Issues and Science and Technology:
In 1996, the crew of an airliner that had just taken off from Salt Lake City International Airport was informed by air-traffic control that the craft was 30 degrees off course. The pilot and copilot’s flight instruments indicated no error. On this day, the weather was good and air-traffic control was able to appropriately vector the aircraft. The flight crew later concluded that electromagnetic interference from a laptop computer being used in the first-class cabin had caused the problem. In his report on the incident, the pilot stated, “I would have really been sweating if it had been instrument flight rules in that mountain area.”
Hmm…Let’s see, DVD player, laptop. What was that about cell phones? The CMU study cited one brand and one model of cell phones that has been reported to interfere with GPS-based nav systems on aircraft and it blames the FCC (who regulates the emissions from cell phones) for not coordinating with FAA to get that under control.
In March 2004, acting on a number of reports from general aviation pilots that Samsung SPH-N300 cellphones had caused their GPS receivers to lose satellite lock, NASA issued a technical memorandum that described emissions from this popular phone. It reported that there were emissions in the GPS band capable of causing interference. Disturbingly, though, they were low enough to comply with FCC emissions standards.
Okay, fine. Let’s get the FCC to talk to the FAA and change the allowable limit for unintended radio emissions from cell phones. But cell phones operating on the proper FCC-mandated frequencies is not a problem. Take a look at this chart. The CMU study actually captured radio emissions from cell phones being used in flight. But note that the emissions captured are WELL out of the bands used by GPS or any other nav system on aircraft.
Had enough? Now, let me net it out.
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The CMU press release was cut and paste and widely misinterpreted as indicating that cell phones could make airplanes fall out of the sky. In reality, DVD players and laptops are probably worse offenders.
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If cell phone use on airplanes is to be allowed, the FCC and FAA need to coordinate and police the unintended emissions made by cell phones, not the currently regulated RF bands.
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DVDs, laptops, and other electronics need an equally hard look at the FCC regs level.
In other words, calm down. Mr. Strauss and others has been talking about this issue for many years. See the papers sited at the end of the IEEE Spectrum article. Someone finally listened. But they heard what they wanted to hear.
Directory Tags: | Wireless | Mobile | DMOZ Wireless |
Carl Howe at Blackfriars has put up two interesting posts. The first cites the diminished effectiveness of TV advertising. The second highlights findings that show user viewing time increasingly split between the Web and TV, but becoming less tolerant of ads on the whole.
After a posting and 
Mobile operators are 
Om Malik
Though I just recently wrote about 
Wi-Fi chip maker 
Suddenly, the telecom world has become delusional. Why? Maybe it’s the numbers — $67 billion purchase price, $120 billion in sales. Apparently, such big numbers are the financial equivalent to LSD.
Honestly, I cannot see how combining two companies that cannot compete in these two areas improves their situation in any dimension.
I love this kind of story: engineer’s dream meets reality.