What Alec Baldwin doesn’t know about air travel
 

There was a quote in the Times from someone, who had spoken to someone else, who may or may not have been an expert. (Says a lot about to-day's reporting standards).
In essence, there was a "one in a million" chance that such a device would impact critical Aviation systems.

I hope that Baldwin is on the flight when that interference takes place.

Billions of passenger kilometres are travelled, and the last estimate that I saw said that there were 90,000 commercial flights per day, worldwide, with 30,000 per day in the USA.

So, in approx 10 days, the one in a million problem will arise at least once.

Everyday that I go to work, I walk around the outside of the aircraft. That walkaround is essentially to check that all the various bits of the airplane are where they are supposed to be. Many of those "bits" are radio aerials. Some look like sharks fins, some are round, some are flat. They come in a variety of shapes and sizes on the various parts of the fuselage and empannages. However they are all carefully built into the physical and electrical structure of the aircraft, so that they work efficiently, and also so that they don't interfere with each other.

Once the passengers board, another 300 odd radio aerials are much less precisely introduced. Given the "cage effect" of an aircraft fuselage, those little radio boxes usually need to up their reception and transmission strength in order to overcome the "cage" obstruction.

Many is the time, when we have to deal with electrical glitches that may or may not be contributed to by the operation of these devices, so for the sake of this one illustration, let's ignore them.

One thing that these phones do without any doubt, is cause interference to the aircrafts radios. That interference manifests itself in a way that is obvious and will be familiar to anybody who has ever tried speaking on a landline telephone with a cellphone placed nearby, or nearby the wiring.

That DA.DA.DA.DA acquisition signal that makes communication difficult, and is solved by moving the cellphone away. When that happens in the pilots headphones (as it regularly does) it can and sometimes does, result in mis-heard and blocked communications. That really is something that is not good. Communication degradation can be a frequent nuisance from other sources as well, but this is one that can be largely eliminated if the laid down rules are properly complied with.

The worst disaster in civil aviation history (los Rodeos 1977,) was in significant part down to communication failure, including hetrodynes that blocked out ATC communications. People often get excited about Ipads taking over sophisticated electronic control systems. In truth the real threat is much more mundane, and one that anyone can experience for themselves, just by leaving their iphone next to their bedside landline tonight.

Beelzebub

As a professional radio engineer who has produced EMC standards and equipment that had to meet them, in my opinion, those who use/fail to switch off cellphones, ipads, wifi etc when told not to are dangerous bloody fools who shouldn't be allowed on an aeroplane.

The only devices that can have radio transmitters in them that can't be switched off are pacemakers and hearing aids. In both cases, the level of the radiation is about 1/10,000 of a cellphone or WiFi - which is why they are acceptable.

Interesting Anecdote
 

I'm sitting here in my favorite coffee shop, reading PPRuNe, listening to a small pocket FM radio. Its a pretty good radio, sensitive but still selective and I'm getting great reception from a local FM station.

Then this guy walks in the door (about 20 ft from me) with a laptop bag slung over his shoulder. Suddenly, the station is nearly buried in static. I know its not objective data, but I'd hate to have to contend with something like this if I were attempting to contact ATC (VHF comms aren't that far from the commercial FM band).

Some people clearly think it's all :mad: and that it doesn't interfere with anything. They probably read it in a magazine or in the Mail and think that these outlets have more knowledge or authority than a fully trained and certified air crew.

Short of outright banning phones from aircraft cabins (which itself would not be that easy to enforce) there is nothing that can really be done to stop the idiots who think they are above the safety of others.

Perhaps mentioning it in the in flight safety video with graphics of how they interfere might get some peoples attentions, or indeed playing that "da, darra, dar, darra, da" noise loudly into the cabin to demonstrate what phones can do the pilots systems might be more effective, but then there's always that all important "should be in the car park in 10 minutes" text to be sent. :=

It is simply the unknown and threat of RF interference. The chance of an electrical device interfering with the avionics is very low but we operate on the side of caution.

LOL!
 

I'm a Dash8 FO and whenever we hear the "Da.da. etc" we check our own phones. Nearly every time it is either the Captains, mine or one of the FA's who've left their phone on in the forward wardrobe.

If a pax has their phone on, we wont hear it in our headphones unless they're in row 1 or 2.

The fact that they don't, and that very little additional emphasis is ever made, leads me to believe that it's not the problem some people want us to believe it is. Having said that I'm FULLY in favour of mobile phones being switched off for the entire duration of the flight so that I don't get arrested at destination for ramming one down a fellow passenger's throat!

But what about me? I can switch my phone to fly-mode but love using my hi-quality camera on my phone to record take offs and landings!?

Thats ok in flight but for take off and landing most airlines operate a blanket ban on electronics.

I'm with Radeng on this. The rules are there for a reason.
In addition to all those antennas, there is also the simple fact that all electronic devices have a series of characteristic frequencies, based on the various electronic switching frequencies inside them. As the world relies on relatively few chipset manufacturers, the chances are that the emissions from one device will match the susceptibility characteristics of another. Not to mention various noisey motors etc. The emitted signals are incredibly low power, and techniques such as shielding, filtering and segregation are used to minimise the risk. Ultimately though, as aircraft equipment is very sensitive and there are so many routes for the interference to inject itself, the risk is there, and in practice is unmeasurable.

As far as I am aware, no-one who has any knowledge of the subject has ever said that the aircraft will roll over and dive into the sea because of interference. What it can do is cause glitches, mis-leading information etc. that can cause the pilots distraction. Therefore during the high workload phases of flight it has been chosen to minimise the risk by removing the potential source of interference. This seems reasonable to me.

As for the rules, they are the rules. I carry a laptop with me. It is designed, and regularly tested, so that it does not produce interfering emissions when operating (well as long as the wireless connection is switched off). I know for a fact that this item will not interfere with the aircraft at any time, but when on a commercial flight I switch it off during take off and landing, as I am instructed to do. It is the rule, and I do not expect an exception. Unless you are an expert in EMC, and an expert in that aircraft's systems and susceptibility levels, then you cannot say anything with any certainty, so shut off and put up with it.

There, it's good to get that off my chest.

Well said sir, the funny thing is I have never seen a pilot abide by these rules!

Really!

I've never seen a pilot not abide by them. What would they be doing with a laptop during take off or landing?

So, ignorant question from me.

Hoe come AA pilots can use an iPad in the cockpit, right next to the computers, displays, control systems, flight control safely, but a passenger cannot use it in an area some distance from these allegedly sensitive devices ?

The screens are in the front, but the computers may not be.

Presumably the pilots will not be using the iPads during take off and landing and will only refer to them instead of a bulky manual when/if needed.

The iPads will also not be transmitting or receiving any data as they will also presumably have these features switched off, if not removed totally, so will not interfere.

I recently partook in an iPad for EFB trial.

We are not allowed to use it at all below 10,000' and it must be switched to flight mode and turned off before departure and prior to arrival. The full range of transmitting and receiving capabilities will be kept as they are used for operational purposes.

It's mostly a farce as we quite often need to refer to the manuals, which it is supposed to be replacing, below 10,000'.

Time for the FAA, or someone's CAA, to collate a series of audio recordings on the flight deck. They need to monitor the FC r/t for internal and external comms. It will take a while no technical problems.

Then do a good media launch and let pax here: "AB123 this is XYZ, descend to #!!!!!!!# and ????? heading." then "AB123, repeat please?" and so on. Pax behave stupidly = Yes. So educate them.