NYT: "Electronics Interfering with flight"
 

Slow news day item:- http://www.nytimes.com/2011/01/18/bu..._r=1&src=busln

“Since 2000, there have been at least 10 voluntary reports filed by pilots in the United States with the Aviation Safety Reporting System, administered by NASA. In 2007, one pilot recounted an instance when the navigational equipment on his Boeing 737 had failed after takeoff. A flight attendant told a passenger to turn off a hand-held GPS device and the problem on the flight deck went away. ”

- Tim

Cap'n Sully was on CNN (I think) the other night agreeing that cell phones and other transmitting devices should be off during flight as he knows of cases where they have interfered with onboard systems.

Yet none of those cases are on the public record or proven. Just because he was a lucky pilot does not make him an expert on electronics and electrical interference.

Junk science. Unless there are peer reviewed results supporting these conclusions, I don't buy the hypothesis that such devices interfere with aircraft electronics outside the far field (> 1m from the device).

I'm actually quite happy to turn off transmitting functions; it's really not a big deal to me personally. (Even though I don't think it's necessary but that's just personal bias.)

I do take issue with turning everything off. For example, my iPad in airplane mode is not transmitting nor is it receiving yet some FAs insist that it be turned off all the way.

what about devices that neither transmit nor receive?
 

Seems to me that small devices that neither transmit nor receive, such as a pocket digital camera, would be even less likely to cause interference. On youtube, there are plenty of videos in the cockpit itself where someone is actually videotaping the takeoff or landing. Obviously, if the pilots thought this was dangerous, they would never let anybody do this, but it seems like people do it quite often, even in the cockpit itself.

http://www.youtube.com/watch?v=6AM_8QSVEkg

His follow-up statement was that there are too many devices to test so we should just turn everything off.

Spiff: Then I call your attention to a peer-reviewed 2003 study published in Spectrum, the journal of the Institute of Electrical and Electronic Engineers (IEEE).

Two excerpts from that article:

(S)purious emissions from cellular phones at the allowable FCC limits would cut dangerously into safety margins for avionics, even when considering "reasonable minimum" radio receiver interference thresholds. More troubling, the study found that intermodulation between some cellular phones caused emissions in the frequency bands used by an aircraft's GPS and distance-measuring equipment.

"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."

planemechanic: While flight crew posting to the system are given anonymity, reports to NASA's Aviation Safety Reporting System are on the public record and readily available. I've copied excerpts from the compilation NASA released about a year ago.

# # #

Synopsis
IN AN APPARENT PED INTERFERENCE EVENT, A PAX'S PORTABLE GARMIN GPS MODEL NUVI 660 ALLEGEDLY INTERFERED WITH A B737 CLASSIC'S (NO GLASS) DME NAVIGATION UPDATE FUNCTION.

# # #

Synopsis
CAPT OF AN A320 RPTS VHF INTERFERENCE ON ZOB ARTCC FREQ FROM A CELL PHONE ABOARD HIS PLANE.

# # #

Synopsis
FLT CREW OF CRJ-700 RPTS THAT AURAL INTERFERENCE IN VHF COMS CEASED WHEN PAX WERE ASKED TO ENSURE ALL FORMS OF 2-WAY COMS WERE TURNED OFF.

# # #

Synopsis
B737-300 CREW HAD ERRATIC LOC SIGNALS ON ILS RWY 13 AND RWY 7 AT JAX. A PAX WAS USING A 'PALM PILOT' AT THE TIME.

# # #

Synopsis
DC-9 FLT CREW RECEIVED A FALSE TCAS RA DURING DEP CLIMB AND INCREASED THEIR RATE OF CLB TO AVOID A FALSE TARGET APPARENTLY GENERATED BY A PAX LAPTOP COMPUTER.

# # #

Anonymous reports of something without proof does not constitute proof of anything. If I file a report that says I suspected that Elvis in Seat 2A was the cause of my navigational error does that make it any more or less true than the reports you cite?

That's the point here. The real world experience of tens of millions of travelers over hundreds of millions of flights indicate that there has NEVER been a confirmed case of injury, death, or navigational deviation due to personal electronic devices. Compare that REAL WORLD EXPERIENCE with a few random pilot reports. Pilots are not experts on the mechanics of the airplane nor electronic emissions, they are (or should be) experts at what they have been trained to do, to fly airplanes.

Here is my view

This stuff isn't magic

The real problem here is that every single electronic device would have to be tested with every aircrafts' avionics in order to verify safety.

Any radio receiver* will contain local oscillators which create mixing products. These mixing products are designed to be attenuated but they can still cause mischief. Clock circuits in computers/cell phones etc. also generate RF.

Interference from things like DVD players can probably be ascribed to poorly shielded motors or motor controllers.

As aircraft wiring ages, connectors work loose and/or corrode. Inadequately fastened connectors can act as a primitive detector that allows stray rf to enter the avionics system.

Without getting into specifics of the above mentioned incidents, it is probable that some of the cases described can be ascribed as much to avionics problems as to the consumer electronics device (I am thinking about the Nuvi causing interference to the CRJ--the first thing that I would check is adequate avionics grounding and that the avionics shielding is properly installed).

As a practical matter, when I fly, everything is disconnected below 10k and during those rare times when flying above 10K in IFR condx. Above 10k, I give the cockpit crew enough credit observe if something is not right...especially if they have outside visual reference. All of the cockpit electronics is redundant and, short of a thermonuclear event, it is unlikely that everything will go south at the same time.

P.S

The claims of the poster who state that he has flown a large number of flights without incident need to be addressed. Avionics interference is a low probability event. Non-interference might just mean that, whatever the number of segments you have successfully completed, it is not enough. If you fly more, you might observe the problem. This gets into Poisson distributions and extreme event analysis which is beyond the scope of this post.

*Local oscillators are associated with superhet receivers which are found in consumer electronics. Regen receivers do not have local oscillators and do not generate mixing products but they have other problems.

Yet he flies for an airline that sells on-board WiFi service.

If a pilot really believes that safety-critical systems on his/her aircraft may fail because of interference from devices that will be on during flight (people often forget to turn of their cell phones, etc.), then that pilot has a duty to do more than just report a suspected incident.

Any electronic device will create RF signals (the exception being devices in perfect Faraday cages, i.e. devices without any electrical input or output). If a common consumer device has a non-trivial likelihood of interfering with some safety-critical system, then that system is flawed by design unless there is a way to guarantee that all consumer devices will be turned off (not possible on commercial aircraft).

I receive Spectrum each month. :)

As planemechanic mentioned, this article uses anecdotal evidence and cannot be construed as testable, reproducible evidence that (in this case the DVD player) the PEDs were actually interfering with the aircraft's electronics.

I realize it would be difficult or perhaps impossible in this situation to prove a negative, as henryf points out, so what's the big deal with just keeping electronics off below 10,000 feet? Yes, I just left my new cell phone on by mistake for an entire flight (pushed the red button too long) and I'm still here. ;)

FWIW I feel the same way about the TSA's X-ray scanners and think the onus should be on their advocates (and lobbyists) to prove that they're safe. In both instances, somebody else's opinion about something even potentially affecting my safety seems presumptuous. YMMV.

In this situation I believe the burden of proof is properly on those who want to use electronics, not those who want them turned off.

Because these are not anonymous reports. NASA removes identifiable details from the published versions in order to allow flight crew to freely report items that may endanger safety without risking punishment or endangering their positions within the industry. NASA's efforts and methodology are good enough to be considered proof within the aviation industry.

Considering that the issue is minor inconvenience from temporary shutdowns of electronics vs. the possibility of death for dozens of people, requiring that everything be turned off at times with the lowest margin for error -- such as takeoffs and landings -- seems the logical action.

No, it does not. When the possibility of death or injury is so extraordinarily low (how many people have died as a result of in-cabin use of consumer electronics?), then inconveniencing tens of millions of travelers is certainly not automatically the logical action.

People balance convenience and risk all of the time, and often far more towards risk than entailed by the topic at hand.

As I have repeatedly said on FT: if the risk were anything but negligible, then Boeing, Airbus, avionics manufacturers, the airlines, etc. should not be flying those aircraft at risk, as all sorts of consumer electronics will almost always be on during all phases of flight.