What are the rules on using gadgets on planes?

Updated July 26, 2004
If mobile phones are banned on planes, what's this man playing at? And why do some airlines prohibit Gameboys, but others don't? As the great summer get-away begins, travellers are no doubt confused. But change could be on the way.
"Hi, I'm on the plane."

Soon mobile phone users could be mouthing just such a greeting into their handsets, while reclining at 30,000ft.

Until now, flying has been one of the last bastions of tranquillity in the almost unmitigated conquest of mobile phones around the planet.

But earlier this month American Airlines demonstrated a new in-flight phone system that could be introduced in two years time. Airbus is working on a similar idea.

Some airlines already offer the next best thing - on-board wireless internet access for laptop users.

Yet at the same time as passengers on one plane are merrily zapping e-mails to friends on terra firma, travellers on another flight are banned from so much as one round of Pokemon on their Gameboy Advance.

The rules governing the use of electronic gadgets on flights are as complex as they are contradictory.

Most UK airlines forbid the use of mobile phones on planes at all times, although some will relax the rules if there is a prolonged delay on the Tarmac.

The reason is two-fold: radiowaves emitted by handsets can interfere with the two-way radio used by pilots, and they can skew the avionics - the on-board systems which control the plane.

However, in the US passengers get more leeway after several airlines last year allowed use of mobiles during taxiing.

Other gadgets, such as laptops, MP3 players, palm tops and pocket video games are generally allowed outside of take off and landing, although, for example, the Irish national carrier Aer Lingus curiously prohibits CD players but not laptops (which house CD players). It is changing these rules.

Bluetooth, Wi-fi and a host of other emerging wireless technologies only muddy the picture further.

The various policies are down to the fact that in the UK and US at least, airlines tailor their own rules based on national guidelines.

Some passengers are highly sceptical though and have seized on inconsistencies to claim that airlines are relying on hunches rather than hard science. Disputes with cabin crew are one of the biggest causes of air rage.

In the US, a team of aviation specialists has been trying to come up with a more coherent policy.

Later this year it is expected to recommend new rules which, according to Boeing's Dave Carson, who sits on the panel of experts, could open the door to in-flight mobile phone systems such as that trialled by American Airlines, and more wireless internet systems.

But how much of a danger are mobiles and other gadgets to an aircraft's safety?

It's a hotly debated issue. After all, on any given flight there's always a handful of passengers who simply forget to turn off their mobiles. Yet last year the US body which governs aviation safety said there had never been an accident caused by interference by passenger gadgets.

However, research published last year by the British Civil Aviation Authority (CAA) found mobile phone signals skewed navigation bearing displays by up to five degrees.

The CAA says it has documented a number of incidents of electronic devices interfering with on-board avionics.

All electronic devices emit electromagnetic radiation. Some, like mobile phones, do so intentionally in order to reach a base station. Others, like CD players, do so unintentionally and have lower emissions levels.

When two devices are close by the electronic pulses can interfere with each other, and theoretically cause a malfunction. The potential for this was highlighted last year when pilots flying over Luton airport picked up the sounds of a crying baby as they tried to reach air traffic control. The problem was isolated to a rogue baby monitor in a nearby house.

Modern electronics have made matters worse. Digital gadgets like CD players emit more than old-fashioned personal stereos while the latest planes have substituted old fashioned hydraulics for microchips.

In addition, mobile companies say using phones on planes can play havoc with their ground networks, because the antennae can't cope with relaying the signal from a phone which is travelling at 500mph.

Yet the idea of a laptop inadvertently downing a plane is unlikely, says Peer Kerry, who heads an international panel on radio interference.

"In reality there appears to be very little problem. During my time I've never received any requests from the CAA or airlines to reduce emissions from these types of products. If there had been serious worries they would doubtless have come to us to discuss it," says Mr Kerry.

"Airlines have to be over-cautious, but that's no bad thing. No matter how small the risk, no one wants to be responsible for a plane falling out of the sky."