U.S. Federal Communications Commission, the USA's top communications regulator, will discuss at a Dec. 15 meeting `relaxing or replacing' a rule that bars people from using wireless devices while flying. This may have positive effects for the cell phone industry, and users in general, by precipitating similar changes in the regulations of other countries. A general cell phone bar has ended up affecting all airlines, mainly because it is feared that cell phone signals may interfere with nagivational equipment. Is this fear unfounded?
U.S. Federal Communications Commission, the USA's top communications regulator, will discuss at a Dec. 15 meeting `relaxing or replacing' a rule that bars people from using wireless devices while flying. This may have positive effects for the cell phone industry, and users in general, by precipitating similar changes in the regulations of other countries. A general cell phone bar has ended up affecting all airlines, mainly because it is feared that cell phone signals may interfere with navigational equipment. Is this fear unfounded?
The Current Approach:
Fear: unfounded, was certainly the attitude taken as early as 1999 by the BBC, who noted that "most of the evidence is circumstantial and anecdotal. There is no absolute proof mobile phones are hazardous." The general attitude taken by the authorities, however, then and now, has been to play safe - if you have ever flown at all, it is certain that you will have heard the announcement to switch off not merely wireless devices, but rather all electronic devices, because they "may interfere with the aircraft's communication and navigation systems."
The current CAA-sanctioned guidelines (registration required), issued on 8 January 2004, is representative of this, and states that: "The use of portable electronic devices on board aircraft by flight crew, cabin crew and passengers presents a source of uncontrolled electro-magnetic radiation with an attendant risk of adverse interference effects to aircraft systems... operators (are required) to take appropriate steps to prevent any such interference."
The 1996 RTCA Study:
In attempts to present this as unnecessary, the popular media frequently quotes from what was apparently the only scientific survey at that time, which is not freely available to the public, and unfortunately these reports seem to be at odds with each other. ZD net reported (in an article about how airlines perpetuated the ban to cash-in on passengers who needed phone access in-flight) that a 1996 study by RTCA, a nonprofit organisation that sets industry standards for aeroplane electronics and commissioned by the U.S. Federal Aviation Administration looked at thousands of flight records and failed to find a single instance in which equipment was affected by a wireless phone. ZD net also states that John Sheehan, who headed the RTCA study says that "The airlines are misleading the travelling public," "(t)here is no real connection between cell-phone frequencies and the frequencies of the navigation" or communications systems; and that the FCC banned cell phone use in aircraft because it was concerned
about cell phones' potential to interfere with ground-to-ground cellular transmission.
This is seemingly at odds with a Wired magazine reports; the RTCA is said to claim that
PEDs could interfere with onboard instruments, including it's latest study in 1996, and that they never studied "intentional transmitting devices" like cell phones and two-way pagers. To make matters worse, Wired also quotes John Sheehan saying "Beyond a shadow of a doubt, (handheld devices) can interfere under very precise circumstances" and that the FCC has never conducted tests to prove cell phones could interfere with signals on the ground, because it considers it "common sense" that cell towers are for terrestrial use, and in
Talk about manipulative journalism.
It is possible that both reports are true, but this would mean that ZD net was being very liberal in it's interpretation of the RTCA study, and very selective in quoting John Sheehan. Alternatively, Wired Magazine (or ZD Net) might simply be wrong. In any case, this is immaterial for our present inquiry. It is perfectly simple to extract from the extant data that the main problem is that all evidence is anecdotal in nature, and there has been no concrete scientific (read: reproduceable) evidence of actual inteference.
New Interference Studies:
In 2003 the UK CAA sponsored research to identify the susceptibility of interference from commonly used transmitting devices of vulnerable avionic equipment. There were very significant anomalies found, including a magnetic compass freezing, and indicators becoming instable. However, the tests were carried out in what are probably worst-case scenarios: where the cellphone was operating at maximum power and located 30cms from the victim equipment, which was utterly unshielded. The first circumstance is actually fairly likely, given that the cellphones will be operating at the fringes of their usable range, but the second is not; the "victim equipment" on newer planes will necessarily be shielded, and only the pilot would ever be located 30cm (12") away from navigational or communication equipment.
However, taking into account an earlier study conducted by the CAA and published in 2nd May 2000, it is clear that a single cellphone transmission at maximum power would exceed, in the flight cabin and avionics bay, by a significant margin, the interference levels used in susceptibility tests for avionic equipment qualified before 1984. This effectively means that it is likely that such anolamies as reported in the 2003 study may occur.
In-seat Airfones:
The next commonly cited objection is the fact that many airplanes do allow seat-installed cellphones. Costs vary, but of USD 3.99 +tax a minute is possible, although Verizon now has plans which allow calls for as low as 10-cents-a-minute. "I question (the prohibition of cell phones in flight) because they have a telephone if you pay for it," said Larry Murphy, vice president of sales and marketing for Flying Food Group. (source: Wired Magazine) However, the fact is that these phones use frequencies which cause less interference, have casing sealed with copper, and have a single antenna in the belly of the plane. This is consistent with the 2002 CAA study, which found negligible interference from phones used in the rear cabin, and found that those frequencies used caused less interference.
Conclusion:
In conclusion, whether the FCC changes it stance or not should be immaterial. For the purposes of maintaining safe air-travel use of mobiles during flights should be restricted, at least until all avionics equipment on a plane is sufficiently "hardened" to withstand such interference.
