Dangers From Onboard Use Of PEDs/Mobile Telephones

There is ample recorded evidence that Personal Electronic Devices (PEDs) including Mobile Telephones are: -

  1. Used during flight whether permitted or not and
  2. Have the potential to interfere with aircraft communications, navigation and, perhaps more rarely, control (engine, FMS) systems.

Yet the Aviation Industry is coming under intense pressure to permit unrestricted use of PEDs, including Mobile telephones, in flight.

The problems of using PEDs in flight are extremely difficult to quantify due to the almost entirely random nature of the Electronic Emissions generated, which depends not only on the power of the emitting device but also on its orientation, the position within the aircraft and whether frequency modulation occurs and magnifies by combining signals from other PEDs, to name but a few of the many variables involved.

In the mid 1990's the CAA issued a Notice to AOC Holders banning the use of Mobile Telephones throughout the flight following an increasing number of MOR's highlighting the interference experienced to the aircraft systems. It would appear, however, that the general public remain unaware of the potential dangers involved and, as revealed by recent tests on 37 internal flights within the USA, continue regularly to use their mobile telephones in flight when specifically banned from so doing.

Aircraft manufacturers are now introducing systems to allow mobiles to be used by providing an onboard 'aerial' (a picocell), that each mobile will automatically detect and remain at the power setting permitted by the aerial.
However, under failure conditions or when mobile phone use is restricted (see below), then enforcement will necessarily have to rely on crew action, which will remain uncertain without the proper detection equipment being provided, as outlined in a JAA Temporary Guidance leaflet No 29, issued in 2001 and never implemented. Thus an element of risk, albeit minor, undoubtedly remains

It is understood that initial restrictions on use may be imposed such that no more than a dozen or so mobile telephones may be used at any one time and only when the aircraft is above 10,000 feet altitude in order not to interfere with ground based aerials. How this could ever be monitored and enforced remains problematical.

Legally banning the use of mobiles and other PEDs known to affect systems, as suggested by a court Judge several years ago, would probably not resolve the problem, as evidenced by the number of people currently flouting the law by using their mobiles whilst driving.

There would appear, therefore, to be a very limited number of realistic options open to the industry:-

  1. Certificate all new build aircraft to ensure that any PED/Mobile used onboard now, or anticipated in future, cannot possibly interfere with any of the aircraft systems. It is most unlikely, however, that the aviation industry would be willing to undertake such action to ensure the integrity of their current fleets of aircraft.
  2. Provide through a Fail-Safe system the facility for unrestricted use of PEDs/Mobiles in flight (assuming the popular demand exists) or
  3. For unmodified aircraft, continue to ban the use of Mobiles throughout the flight and other PEDs during critical stages of flight and ensure compliance by providing detection and warning (and possibly jamming) equipment to the Flight and Cabin Crews in order to pinpoint immediately the source of any emissions likely to provide interference. If/when detected take action against the person responsible for endangering the safety of the aircraft, as now occurs in China (resulting in a US $250 fine).

Meanwhile, it is recommended that greater publicity and information be provided to the public of the potential hazards associated with use on unmodified aircraft and the issues that have arison with the new picocell systems. Then, if justified by this review, further in flight research should be undertaken by the CAA/EASA in order to resolve any issues.. Unrestricted use of Mobiles in flight must be delayed until the safety of their use has been proven and guaranteed not to be a problem. The question remains, what, if anything has changed in the last ten years to make unrestricted use of mobile telephones onboard aircraft safe? Finally, the Air Safety Group recommends that the JAA Temporary Guidance Leaflet (JAR-OPS) No. 29 published in October 2001 be implemented to require onboard detection equipment enabling the Crew to detect any unauthorised use of mobile telephones, particularly during critical phases of flight.

Following the incident in February 2008 where a B747 exceeded its selected airspeed and deviated from its required track because of a business class passenger refusing to switch off his mobile telephone, the Group wrote to both Flight International and the AAIB (See Letters section) raising the possibility of one or more mobile telephones or other electronic devices possibly contributing to the B777 accident at Heathrow by countering the demand for increased fuel flow and power at a critical stage during final approach. This has subsequently proven not to be the case but the February 2008 B747 incident remains as a warning of potential interference in the older generation of aircraft.

In response to questions in the House of Commons, the Aviation Minister gave an assurance that G registered aircraft would not be permitted to use mobile telephones in flight until both the CAA and EASA could ensure their safety. The Group remains concerned that the aviation industry may not fully appreciate the potential hazards associated with the introduction and use of mobile telephones and other electronic devices onboard aircraft in flight, especially where reliance has to be placed on flight and cabin crew announcements to ensure their non use at various key moments during take-off and landing. It is felt there will inevitably be those who, either inadvertently or deliberately, will fail to comply. The Group will continue to keep this issue under review