"A
NASA publication details the fifty most recent reports to the
Aviation Safety Reporting System (ASRS) regarding "avionics problems that may result from the influence of passenger electronic devices." The nature of these reports varies widely. Some merely describe passengers' interactions with flight crews when asked to stop using an electronic device. Other reports amount to crews reporting an anomaly experienced at the same time a passenger was witnessed using a mobile phone. A few reports state that interference to aircraft systems was observed to appear and disappear as that particular suspect device was turned on and off. One entry in the ASRS, designated ACN: 440557, reports a clear link where a passenger's DVD player induced a 30-degree error in the display of the aircraft's heading, each time the player was switched on. However, this report dates back to 1999 and involves a
Boeing 727, an old type of aircraft that is no longer in use by airlines today.A 2003 study involved three months of testing with
RF spectrum analyzers and other instruments aboard regular commercial flights, and one passage reads:
...our research has found that these items can interrupt the normal operation of key cockpit instruments, especially Global Positioning System (GPS) receivers, which are increasingly vital to safe landings. Two different studies by NASA further support the idea that passengers' electronic devices dangerously produce interference in a way that reduces the safety margins for critical avionics systems.
There is no smoking gun to this story: there is no definitive instance of an air accident known to have been caused by a passenger's use of an electronic device. Nonetheless, although it is impossible to say that such use has contributed to air accidents in the past, the data also make it impossible to rule it out completely. More importantly, the data support a conclusion that continued use of portable RF-emitting devices such as cell phones will, in all likelihood, someday cause an accident by interfering with critical cockpit instruments such as GPS receivers. This much is certain: there exists a greater potential for problems than was previously believed.
A 2000 study by the
British Civil Aviation Authority found that a mobile phone, when used near the cockpit or other avionics equipment location, will exceed safety levels for older equipment (compliant with 1984 standards). Such equipment is still in use, even in new aircraft. Therefore, the report concludes, the current policy, which restricts the use of mobile phones on all aircraft while the engines are running, should remain in force.
Critics of the ban doubt that small battery-powered devices would have any significant influence on a commercial jetliner's shielded electronic systems. Safety researchers Tekla S. Perry and Linda Geppert point out that shielding and other protections degrade with increasing age, cycles of use, and even some maintenance procedures, as is also true of the shielding in PEDs, including mobile phones.
Several reports argue both sides of the issue in the same article; on the one hand they highlight the lack of definite evidence of mobile phones causing significant interference, while on the other hand they point out that caution in maintaining restrictions on using mobile phones and other PEDs in flight is the safer course to take.[size=8333px]"[/size]