aviation mythbuster
Join Date: Mar 2000
Location: Above the 23.5 parallel Australia
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On a particular aircraft that I flew the cellphone would cause a "ghost" aircraft return on the TCAS. Ask the pax to check their phones and the "ghost" aircraft would soon disappear.
Join Date: Aug 2006
Location: Here
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There is a big difference between an A320 and a 212. The compelxity of the avionics is vastly different. What everyone has neglected to look at is not the avionics but the wiring that connects the avionics. Manufacturers are currently obsessed with HIRF(high intensity radiated field) With the exception of DC power and ground wires pretty much everything else is run through a shielded wire. That means that the odds of a rogue signal being radiated onto the line are low, but still possible. Consider that in an A320 a run may be a 100 feet or so. That is a long way and will have many disconnects. That is a lot of chances for the shield line to break or be in poor condition. A perfect opportunity for someone in seat 13F to radiate his cell's signal into an AFCS line.
The other thing no one has mentioned is that the signals travelling down wires in a modern aircraft are not analog or high voltage. In terms of voltage some signals can be in the millivolts. Sensors can be looking for a slight miliohm change to trigger a caution. Things are sensitive. This is quite advantageous as wire size can now be decreased significantly. Of course it also means that a cell phone signal may wreak havoc under the right circumstances. For those skeptics consider how many times a simple connector removal and cleaning will solve a problem. Why? Simple low level signals - a dirty connection adds resistance where there should be none. The result is erroneous data or no signal at all.
In my career I have seen, heard and experimented with radiated interference. It is quite interesting. I am interested to see how Boeing is going to offer cell and wireless service in the 787. As they say where there is a will there is a way. Unfortunately there is a will which means there will be no where that will be cell phone free.
For the poster who had the igniters go off that sounds like a very interested experience. I have never heard of something that serious. I am guessing the aircraft was FADEC or EEC equipped?
For the poster who thinks there is more electronics in his BMW than an aircraft....Stop posting, unless of course you fly a cub. Even the databus architecture on a regional airliner is amazing, let alone a 777. Your post shows your ignorance of the industry.
The other thing no one has mentioned is that the signals travelling down wires in a modern aircraft are not analog or high voltage. In terms of voltage some signals can be in the millivolts. Sensors can be looking for a slight miliohm change to trigger a caution. Things are sensitive. This is quite advantageous as wire size can now be decreased significantly. Of course it also means that a cell phone signal may wreak havoc under the right circumstances. For those skeptics consider how many times a simple connector removal and cleaning will solve a problem. Why? Simple low level signals - a dirty connection adds resistance where there should be none. The result is erroneous data or no signal at all.
In my career I have seen, heard and experimented with radiated interference. It is quite interesting. I am interested to see how Boeing is going to offer cell and wireless service in the 787. As they say where there is a will there is a way. Unfortunately there is a will which means there will be no where that will be cell phone free.
For the poster who had the igniters go off that sounds like a very interested experience. I have never heard of something that serious. I am guessing the aircraft was FADEC or EEC equipped?
For the poster who thinks there is more electronics in his BMW than an aircraft....Stop posting, unless of course you fly a cub. Even the databus architecture on a regional airliner is amazing, let alone a 777. Your post shows your ignorance of the industry.
