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You know, if they are saying that it didn't travel for seven hours, it is entirely possible there could have been a mechanical issue. Any physics people out there? Something I would like to know is that cell phones can cause interference with plane communications, although there's conflicting info on that. Would electomagnetic inteference, or EMI, come in to play? Would the radiation given off by a full cargo load of lithium ion batteries be enough to cause an issue with the plane's onboard communication systems? It was revealed that the cargo was carrying a lot of lithium ion batteries. Could this have caused inteference with the plane enough to knock out the nav systems? I could see this scenario where there was no fire, yet enough to cause an issue and the pilots could not determine the proper altitude, went to 43,000 feet for 23 minutes and died. Still, they say the flight path was manually entered.
No. Any critical system or subsystem on the aircraft that could be influenced by such a thing has shielded wire to protect against electromagnetic interference. The cell phone thing is more of an FCC requirement because they don't like phones rapidly changing towers (like they would in an airplane).
Generally, a larger hazard are unbonded external panels of the aircraft - particularly composite panels. As the aircraft flies through the air, particularly in clouds, positive ions are attracted to the negative charge of the aircraft. Ordinarily, this behavior is dealt with by means of static dischargers on the trailing ends of the wings, and vertical and horizontal stabilizers. The static dischargers are small, pointed objects. Electrical charges will evenly distribute themselves around a perfect sphere BUT the "pointier" a conductor is, the surface charge density at the point will be greater than somewhere else. Usually, as the plane flies along, these charges begin to accumulate and steadily dissipate at the static dischargers - which are small pointy object.
However, if a panel is not bonded properly, the positive ions will still be attracted to the aircraft, and a charge will begin to build up on the unbonded panels because they have nowhere to go. Ultimately, if they have nowhere to go, an electromagnetic field begins to develop around the panel and we're talking in the 100,000 volts or more range. The electromagnetic field will decrease in strength at a rate of 1/r^2. That amount of static charge can cause radio interference - usually on the VHF radios depending on the proximity of the panel(s) to the radio antennas.
Sometimes flight crews experience what is referred to as St. Elmo's Fire when a radome (the nose cone of the aircraft) is not bonded properly. The charges build up so much that there is a corona effect (a discharge event) that happens and makes for a very pretty light show.
This might be a little deep but Walter Lewin, my favorite MIT professor, explains it the best.
This is also why aircraft can deal with lightning (because charges accumulate on the SURFACE of the conductor). And, yes, you're perfectly safe from it.
Interesting GCSTroop.. so there is the split, or a crack ( or a Y) Excellent conclusion of unbonded material. It made my headache just a little bit lighter.
Close but no cigar. The panels build up an electrostatic charge. That does not cause any comm problems...but if it begins to discharge than you can have current flow and with current flow you can get RF noise. To really shut things down by need to form an arc...which is a very powerful broad band noise source.
A great video by the way...I could not break away even though I had things I needed to do.
I think you're referring to the Emergency Locator Transmitter (ELT). I'm only familiar with those designed for small planes but imagine they're all similar. The ones I've seen are designed to activate in a crash (from forward Gs). They transmit to a passing overhead satellite (and in some cases, to an overhead aircraft radio tuned to the standard emergency frequency), and it can take a couple hours for a satellite to pass over the crash site and receive the (line of sight) transmission.
The problem with that "couple hours" is that ELTs don't transmit much from below water, especially deep water. So if the ELT activated, there may have not been a satellite to receive the signal for a couple hours, and in that couple hours, it could well have sunk to the ocean floor. Also, they don't always go off as planned. If there's not a sudden forward stop, it may not activate. If the plane isn't intact when it hits, it may not activate. I think it's safe to say, in this instance, either the ELT did not activate or it had sunk into the ocean before a satellite passing overhead was able to receive the signal. They do have their own batteries, so that's not a problem; however, the batteries are only designed to last for a month or so.
Close but no cigar. The panels build up an electrostatic charge. That does not cause any comm problems...but if it begins to discharge than you can have current flow and with current flow you can get RF noise. To really shut things down by need to form an arc...which is a very powerful broad band noise source.
A great video by the way...I could not break away even though I had things I needed to do.
Perhaps I wasn't clear in my description... I was trying to type on my phone. You're correct. It's the discharge that creates the comm problem. No argument there. Once the panel reaches a point of saturation, there will be a discharge though.
No. Any critical system or subsystem on the aircraft that could be influenced by such a thing has shielded wire to protect against electromagnetic interference. The cell phone thing is more of an FCC requirement because they don't like phones rapidly changing towers (like they would in an airplane).
Generally, a larger hazard are unbonded external panels of the aircraft - particularly composite panels. As the aircraft flies through the air, particularly in clouds, positive ions are attracted to the negative charge of the aircraft. Ordinarily, this behavior is dealt with by means of static dischargers on the trailing ends of the wings, and vertical and horizontal stabilizers. The static dischargers are small, pointed objects. Electrical charges will evenly distribute themselves around a perfect sphere BUT the "pointier" a conductor is, the surface charge density at the point will be greater than somewhere else. Usually, as the plane flies along, these charges begin to accumulate and steadily dissipate at the static dischargers - which are small pointy object.
However, if a panel is not bonded properly, the positive ions will still be attracted to the aircraft, and a charge will begin to build up on the unbonded panels because they have nowhere to go. Ultimately, if they have nowhere to go, an electromagnetic field begins to develop around the panel and we're talking in the 100,000 volts or more range. The electromagnetic field will decrease in strength at a rate of 1/r^2. That amount of static charge can cause radio interference - usually on the VHF radios depending on the proximity of the panel(s) to the radio antennas.
Sometimes flight crews experience what is referred to as St. Elmo's Fire when a radome (the nose cone of the aircraft) is not bonded properly. The charges build up so much that there is a corona effect (a discharge event) that happens and makes for a very pretty light show.
This might be a little deep but Walter Lewin, my favorite MIT professor, explains it the best.
This is also why aircraft can deal with lightning (because charges accumulate on the SURFACE of the conductor). And, yes, you're perfectly safe from it.
Excellent description. St. Elmo's fire is an amazing phenomena.
I keep an eye out for eye-level static wicks (pun intended).
Excellent description. St. Elmo's fire is an amazing phenomena.
I keep an eye out for eye-level static wicks (pun intended).
Man... I have come very close on several occasions to introducing my eye to a static wick. That's one of those things that scares the crap out of me. Gives me the creeps thinking about what one would do to my eye!
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