ABC News documentary - are cell phones dangerous in flight - myth or fact?

[HeadingSouth]

most planes have already phones on board.

rather than doing EMI investigations which cannot clear any doubt yet cost a multitude of $$$ - why Not supporting the phones that are already on board instead?

saves as well using some $$$ for investigations whether miss business' mobile phone in seat 2A indeed caused the crash and took the lives of many a passenger...

[ChristiaanJ]

HeadingSouth,

why not supporting the phones that are already on board instead?

What do you call "supporting"?

I see two snags.

1. With cell phone and game console and computer add-on makers bringing out new models about every month, if not every week, a list of "approved" devices (which is what I assume you mean, correct me if I misunderstood) would be obsolete in six months.

2. While there are FCC standards for electronic devices, they assure at best they don't interfere too much with your television and automatic garage door opener.
So far as I know, there are NO standards in existence against which you could certify a PED as being approved for use on board an aircraft.

[matt_hooks]

ChristiaanJ, I think it's a fairly well known fact that mobile phones DO emit radiation on frequencies different to the actual transmission/reception frequencies. All one needs to do is stand a mobile phone near to a car radio whilst it is ringing to establish that. Now a car radio, whilst not safety critical, would not be particularly succesful if it were easily affected by EMI. The average electronic ignition system in your modern car causes quite scarily high energy levels, even outside the system, and yet in general car radio sets seem to be immune to this interference. Given this fact, it is quite concerning that a mobile phone can cause audible interference.

Granted, without thoroughly analysing the systems and emissions, one cannot say what component of the system is being affected adversely. It's quite possible that the interference is occuring in the (relatively) unshielded speaker lines rather than the internals of the system itself, but how well shielded are the transmission lines for navigational equipment? I personally am in no doubt that, in a light twin at least, a mobile phone on board CAN cause erroneous or misleading indications, I've seen it with my own eyes. Whilst this is not a direct safety issue, in that the interference is sporadic and short lived, there is always the possibility that it could lead to a pilot disbelieving his instruments and becoming disorientated.

As for a commercial environment, I think that in general the ability to use mobile phones on planes would be generally unpopular. However the ability to use wireless internet access might not prove so unpopular. The fact is, however, that the people who will decide (safety legislation aside) whether such services are supplied will be the airlines. Now some may take the view that it might be unpopular to provide such a service, but I would hazard a guess that many will find it hard to turn down another possible revenue stream. So if it can't be proved to be unsafe, I think we will probably see more widespread provision of such services onboard.

[Saint-Ex]

I witnessed one incident in a tri-jet when the autopilot was twitching the controls. A search of the cabin for active mobiles was made but it turned out to be the captain`s `phone in his flight bag. Once turned off, the autopilot gave no more problems. There was also an instance in my company on a B734 where a port engine surge was put down to a passenger in a window seat alongside the engine using his mobile. In reply to an earlier letter about fbw, an A320 was subjected to extreme exposure by a radar scanner centered on the avionics bay while configured in flight mode with engines running. I believe this was continued for several hours and no interference was recorded . This was one area where certification authorities really had to be convinced.

[airsupport]

IF they are anywhere near as bad as some of you are making out, why is it in some Countries like the USA, mobile (cell) phones are allowed to be used when on board the aircraft on the ground, at the gate but also during taxiing out and in?

As I said before I hope they are NEVER approved, but for comfort's sake NOT because of safety.

[matt_hooks]

Airsupport, safety is the only thing that will stop them being approved! Unfortunately most airlines see only the possible extra revenue stream, not the consensus of opinion that having them on board would be a bad thing.

[airsupport]

So what you are saying is that although they are NOT a danger to the safe operation of the flight, ban them on safety grounds anyway as it is the ONLY way to stop them?

The same would apply to babies and small children.

[ChristiaanJ]

Originally Posted by "Saint-Ex

I witnessed one incident in a tri-jet when the autopilot was twitching the controls. A search of the cabin for active mobiles was made but it turned out to be the captain`s `phone in his flight bag. Once turned off, the autopilot gave no more problems. There was also an instance in my company on a B734 where a port engine surge was put down to a passenger in a window seat alongside the engine using his mobile.

You've just added two more bits of 'anecdotical' evidence to a large database.
Why isn't this followed up more?
"Illegal", and simply unintentional, use of mobiles, and ohter PEDs is increasing all the time.

In reply to an earlier letter about fbw, an A320 was subjected to extreme exposure by a radar scanner centered on the avionics bay while configured in flight mode with engines running. I believe this was continued for several hours and no interference was recorded . This was one area where certification authorities really had to be convinced.

Sounds like a particularly pointless exercise to prove/disprove anything. What finally comes out of a wx radar scanner is almost pure X-band radiation (assuming a recent one... are any C-band ones still around ?). Virtually none of that penetrates into an airframe.

We're talking about baseband interference (800MHz not being too far from DME frequencies), and spurious emissions (such as PEDs causing interfrence on NDB frequencies).

[West Coast]

"but also during taxiing out and in?"

Not meaning to be overly pedantic, but its only on the way in. The FAR's require them to be off to be able to taxi. Not to say its rigorously enforced as we all have seen people bent over out of the site of the FA's using them.

[airsupport]

I freely admit I do NOT know the regulations there, just while I was living and working in the USA some years ago, I did a lot of positioning flights as a passenger and on many of these flights passengers were using these mobiles (cells) both during taxi out and in.

[Contacttower]

We're talking about baseband interference (800MHz not being too far from DME frequencies)

Someone mentioned that his mobile had interfered with the DME in his aircraft on the GPS thread.

[Saint-Ex]

Sounds like a particularly pointless exercise to prove/disprove anything. What finally comes out of a wx radar scanner is almost pure X-band radiation (assuming a recent one... are any C-band ones still around ?). Virtually none of that penetrates into an airframe.

Christiaan, don`t know which type but Gordon Corps reckoned the most powerful signal they could find.