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Fliers Must Turn Off Devices, but It’s Not Clear Why

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Re: Fliers Must Turn Off Devices, but It’s Not Clear Why

#261
post #142

Earlier quoted context omitted.

I'd be very interested in that data, mostly because a handheld device capable of producing enough EM radiation to interfere with a cockpit from dozens of feet away (at a minimum) through metal bulkheads seems implausible, at the least. Remember that EM fields are subject to inverse-square law. If it was possible, I can't imagine that the TSA would let us carry as much as a 9-volt battery on board. Even if it were pos…

> Remember that EM fields are subject to inverse-square law. Not inside a metal tube, they're not. This is not to say that I'm a "believer" one way or the other, but you should also think about it in comparison to the signals that the navigation equipment is trying to receive with its omnidirectional antenna. I.e., a strong CB radio 26,000 miles away. It wouldn't take any power at all to interfere with it, if the int…

"which are continually changing due to doppler effects"

Doppler effects will be extremely small, since the greatest speed differential you'll see will be twice the speed of an airplane (when two planes are moving directly towards or away each other), which is not a substantial fraction of the speed of light. There will be some shift, but not nearly enough to bump a device from non-interference to interference. Or did I misunderstand something?

Re: Fliers Must Turn Off Devices, but It’s Not Clear Why

#262

Earlier quoted context omitted.

I have a BS in EE, a masters in Aeronautical Engineering, and fly for a living. I currently work in developmental flight test. Allow me to explain a couple of reasons why you should turn off your cell phone when flying: 1: It is not a "safety charade." See my other posts about EMC in this topic. 2: Even if you don't care about anybody else's safety, or even your own for that matter, it's still in your own best intere…

1. I have a masters in EE, but more importantly I have common sense that tells me that millions of flights have been conducted in the cell phone era without an issue. Please stop the fear mongering on this. 2. I put it into WiFi only mode about 10 minutes after takeoff when I can't get a signal anymore and just turn it back on when we are a half hour within landing. It allows me at least a half hour of emails and tex…

>millions of flights have been conducted in the cell phone era without an issue.

First of all, this is not true. I have read aviation safety reports that cite consumer electronics as a contributing factor. Second of all, the fact that no major mishap has been attributed to consumer electronics is probably due in large part to the controls in place. There may be a few individuals who don't care about safety who disregard the rules, but as long as the overwhelming majority of passengers comply, the chances of an incident are dramatically reduced.

Aviators are tought a "swiss cheese" model of mishaps: there are safety precautions in place (equipment, procedures, etc.) to prevent mishaps, which you can visualize as slices of swiss cheese, with holes in them. The holes represent things that prevent a particular precaution from working properly: broken equipment, failure to comply with procedures, etc. A hazard might make it past one precaution by slipping through one of these holes, but then get stopped by some other precaution. A mishap occurs when enough holes line up in a row for a hazard to get all of the way through. In most mishaps, there are three holes that lined up to make the mishap happen. For example, bad weather alone would probably not cause a mishap, nor would a hyrdaulic malfunction alone or a slightly low fuel load alone, but when you get all three together, shit gets out of hand and a mishap can happen. On a flight where nothing else goes wrong, consumer electronics alone are not going to cause a mishap, but on a flight where a couple of other things are going wrong, a single cell phone might be all it takes to tip the scales from "a really bad day for the pilots" to "mishap."

>Please stop the fear mongering on this.

I have personally experienced degradation of safety-critical systems in-flight due to EMI from on-board devices, including devices that are not designed to be transmitters. Nothing you carry onto a plane is going to cause it to explode without warning or go completely out of control (which are a couple of straw-men I have seen in this topic). What can, and does, happen, is that safety-critical avionics don't work right. During critical phases of flight (takeoff, departure, approach, and landing), this could be a contributor to a mishap. If your ILS goes haywire when you're in the middle of shooting an approach in actual IMC, you've got a big problem; likewise, if you can't talk on certain radio frequencies in the terminal area due to noise interference, you've got a problem.

>I put it into WiFi only mode about 10 minutes after takeoff when I can't get a signal anymore and just turn it back on when we are a half hour within landing.

If you have a GSM phone, then allow me to speak for every pilot you have ever been a passenger to: fuck you. No, really: fuck you. Put your GSM phone next to a cheap set of speakers: it will periodically make a noise (especially if you are sending/receiving calls or data, or if your phone is searching for the network). The same thing happens with most ILS receivers and with the ICS on many planes. So first, they'll have to use some other approach rather than ILS, which may not have been their primary plan. Then, imagine trying to run checklists and land a plane with that shit going off in your ears.

Even if you have a CDMA phone, there's a good chance you're interfering with something, making the lives of your pilots that much harder at a time when they can ill afford additional distractions.

Re: Fliers Must Turn Off Devices, but It’s Not Clear Why

#263

Earlier quoted context omitted.

1. I have a masters in EE, but more importantly I have common sense that tells me that millions of flights have been conducted in the cell phone era without an issue. Please stop the fear mongering on this. 2. I put it into WiFi only mode about 10 minutes after takeoff when I can't get a signal anymore and just turn it back on when we are a half hour within landing. It allows me at least a half hour of emails and tex…

> millions of flights have been conducted in the cell phone era without an issue. First of all, this is not true. I have read aviation safety reports that cite consumer electronics as a contributing factor. Second of all, the fact that no major mishap has been attributed to consumer electronics is probably due in large part to the controls in place. There may be a few individuals who don't care about safety who disre…

You okay, bro? Unstable people like yourself are more of a danger to flying than cellphones ever could be.

Re: Fliers Must Turn Off Devices, but It’s Not Clear Why

#264
post #8

There is actually a very logical, sensible reason to have everyone power off and stow their devices during takeoff and landing, and this story disappointingly failed to cover it: By far the most likely time for any accidents or incidents to occur is during takeoffs and landings. If everyone has 15 objects out and is busily typing away, it's going to be tht much more difficult for flight attendants to get everyone's a…

The FAA/TSA alway justify things in terms of "safety" and "security", but never calculate the massive costs associated with seizing billions in toiletries and productivity. Let's calculate that. There are about 800 million[0] passengers on domestic and foreign owned airlines in the US market, with many people flying more than once per year. Each person is taxed between 1-2 hours in terms of "safety" regulations, rang…

Delta actually does the seat back (or on the overhead monitors depending on the age of the plane) thing during taxiing to the runway. You can actually go watch it at http://www.youtube.com/watch?v=MgpzUo_kbFY

The camera angles and lighting are a bit surreal when watching it after having been up for 96 hours though.

Re: Fliers Must Turn Off Devices, but It’s Not Clear Why

#265
In 1999 I was on a flight and sat next to an EE who worked for Boeing on commercial airliners. He said that there was virtually no chance that a cell phone would cause any interference. He said that as far as he could tell the FAA rules stemmed from the FCC that stemmed from the cell carries pressuring the FCC not to allow it. The reason he suggested was that cell phones at altitude have line-of-sight to dozens of cell towers. As airplanes full of cell phones fly through the air they associate and disassociate with cell towers very quickly. The towers have to switch the handsets from tower to tower more quickly than usual causing a lot of network traffic signaling overhead between cell sites. Here's a wikipedia article on this http://en.wikipedia.org/wiki/Mobile_phones_on_aircraft#Cell_...

Edit: added URL

Re: Fliers Must Turn Off Devices, but It’s Not Clear Why

#266
post #214

Earlier quoted context omitted.

In other parts of the world their are trains, which are faster than cars and provide tables and often electricity and wifi, making them a pretty compelling substitute.

I don't think there's many places were a train is a good substitute for a 5+ hr flight.

I live in Washington, DC and Washington, DC -> NYC is a common trip. The train is a much better way to go. From Washington, DC, it's a short metro ride to get to union station. The train takes about 3 hours to NYC but it gets you right into Penn Station. This is much better than having to go to a suburb to get to the airport and landing in another suburb and having to get downtown. I'm a fan of trains. And... rail travel isn't dead time at all. I'm able to work on my laptop and I don't have to worry about the person in front of me putting their chair back full tilt crushing my opened screen.

Re: Fliers Must Turn Off Devices, but It’s Not Clear Why

#267
post #67

The last time I flew, most of the people around me didn't know the difference between "airplane mode", "standby", and "off". I'd bet that at least 80% of the phones on that flight were full on despite the efforts of the crew and the device's owners. Everyone turning off everything successfully before takeoff is pure fiction.

Cell phone transmissions are much less frequent when the phone is idle than when it is in active use. Even if people just stop talking on the phones, it's better than nothing.

True. But I bet a phone on the airplane idle is more active than on the ground idle due to network searching.

Re: Fliers Must Turn Off Devices, but It’s Not Clear Why

#268
post #8

There is actually a very logical, sensible reason to have everyone power off and stow their devices during takeoff and landing, and this story disappointingly failed to cover it: By far the most likely time for any accidents or incidents to occur is during takeoffs and landings. If everyone has 15 objects out and is busily typing away, it's going to be tht much more difficult for flight attendants to get everyone's a…

The FAA/TSA alway justify things in terms of "safety" and "security", but never calculate the massive costs associated with seizing billions in toiletries and productivity. Let's calculate that. There are about 800 million[0] passengers on domestic and foreign owned airlines in the US market, with many people flying more than once per year. Each person is taxed between 1-2 hours in terms of "safety" regulations, rang…

How many average human lifespans is 1.6 billion hours?

Re: Fliers Must Turn Off Devices, but It’s Not Clear Why

#270

Earlier quoted context omitted.

The FAA/TSA alway justify things in terms of "safety" and "security", but never calculate the massive costs associated with seizing billions in toiletries and productivity. Let's calculate that. There are about 800 million[0] passengers on domestic and foreign owned airlines in the US market, with many people flying more than once per year. Each person is taxed between 1-2 hours in terms of "safety" regulations, rang…

How many airports make you spend an hour or two going through security? When flying, I usually spend an hour or two in total at the airport, but that includes check-in, security, waiting for and boarding plane, then de-planing and sometimes waiting for luggage. Not to mention the transport time to and from the airports. Security and safety is a pretty insignificant part of that time, and waiting in line at the airpor…

JFK/EWK and SFO.
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