The FAA Discovers HERF

On a recent series of US Scare plane flights, I noticed a new flight attendant spiel.

"We're descending below 10,000 feet for our approach into (safe major metropolitan airport). Please turn off all laptop computers, CD and cassette players. Thank you for flying US Scare."

In the July 26, 1993 issue of Newsweek, the following appeared.

"On an uneventful flight over the Southern Pacific last February, the 747-400 pilot stared wide-eyed as his navigational displays suddenly flared and crackled. The data made no sense. But a flight attendant was already whisking a passenger's laptop computer up to the flight deck. When the crew turned it on, the navigation displays went crazy. They returned to normal when the crew switched off the laptop. The plane reached its destination safely. Investigating the incident, Boeing engineers bought the same model laptop and tried to replicate the glitch in another 747. They couldn't." And then, "In a holding pattern 13,000 feet somewhere above the southeastern United States, the pilot saw the guidance computers and controls that maintain the craft's lateral stability shut down. A passenger in Row 1 - directly above the flight computers and near the navigation antennas - was using a radio transmitter and receiver, a flight attendant said. The first officer hurried back and the told the man to shut it off; the systems blinked back on. Five years later, no one can explain how, or even if, the radio zapped the computers."

Welcome to the world of HERF.

HERF is an acronym for High Energy Radio Frequency, and holds potential disaster within its enigmatic description.

Over the last couple of years, Security Insider Report has discussed HERF and its potential for disrupting electronics (June, 1992, October, 1992, November, 1992, January, 1993). Word is getting out.

A fundamental axiom of electronics is at the heart of the phenomena, and needs to be understood to appreciate the potential severity of the problem. An electric current creates a magnetic field, which travels at the speed of light in all directions. This is the principle of radio and TV and cell phones.

If you stick a wire in the air, and connect it a completed circuit, a magnetic field will induce a current flow. Again, radio and TV. If you modulate the signal with information, then the information can be sent from one place to another almost instantaneously.

On the other hand, we have all heard interference on the radio or a cell phone when passing through a tunnel or on a bridge.

HERF is the magnetic field, intentional or not, that when detected by an electric circuit can disrupt its operation to varying degrees of intensity.

A HERF signal, if properly aimed at an electronic target can so disrupt its operation as to render it useless.

This may well be what's happening to the 747-400's that experience anomalies such as those Newsweek described. You see, the latest generation of planes are known as "fly-by-wire", meaning that the planes functions, from nose to tail are controlled by a maze of computers and 145 miles of wires and cables. Many of these signals are so-called low-level signals, high impedance low voltage signals that are the most susceptible to interference.

Now, a laptop computer or CD player will emit unintentionally, a quantity of radiation by its very nature. Despite the regulations made by the FCC to minimize electromagnetic emissions on consumer equipment, the shielding is far from complete. While the home computer may no longer screw up a TV picture as it did in the days of the TRS-80 and VIC-20, enough signal leakage occurs as to be of concern to the DoD and NSA. That's why they have the Tempest program - to stop all leakage at all costs. That's an intelligence concern, but the principle is the same.

While the FAA and most airlines deny that there are any safety concerns to worry about, malfunctions of avionics systems do bring up serious public safety issues. Since 1990 the FAA has complied almost 100 reports of such occurrences with a six-fold increase this year alone. Why? We suspect, as many do, that fly-by-wire planes are indeed affected by computers and digital music systems.

The number of potential paths that a radiated signal can take include flowing down the metal skin of the airplane, down the conduits of the wiring, directly into low level paths, or bouncing off of metal surfaces directly into antennas. Another possibility is one of resonance; where the radiated signal and the affected circuitry operate at the same frequency, thus increasing the apparent effects. A 10 MHz signal tends to attract and apparently "multiply" the energy of a nearby induced 10MHz signal. It's the nature of the beast.

Another culprit is the FCC testing method for emissions certification of consumer products, especially computers. The tests as run by the manufacturer are idealized, under nearly perfect conditions. But, if you add RAM or a bigger hard disk, or one from another manufacturer, or use a higher speed CPU or add a modem, the rules change, and the emissions characteristics change. The power supply is drained faster, the clock cycles differently, and the location of the added RAM creates new magnetic patterns that might not still
meet the barely adequate FCC emissions standards.

Back in the mid 1980's, I worked for computer companies who spared no effort in minimizing compliance with the FCC. The bare minimum configurations were tested, and often we had to run back and forth to the factory to find the one single, unique computer system that would comply. Manufacturing tolerances and the bottom line took precedence over compliance. In many cases, the mere addition of 256RAM, bringing the machine up to a fully loaded 640K, would literally increase the emissions by a factor of 10! The FCC be damned. And then the addition of peripherals were even worse. Only those peripherals which actually had a port or a cable were required to have their own FCC compliance, but there's no provision for the synergistic effects of different manufacturer's products working together and still meeting the specifications. It was a total scam by every company I worked for. The edict was clear: Do whatever it takes to pass the test, for every day we're not selling, we're losing money.

Also, some of the approved FCC testing laboratories were less than on the up and up. A typical suite of tests can run from $2500 to $25,000 and take 6 weeks or so; a costly death knoll for the competitive computer biz. But a double payment, in cash, often insured that the product was guaranteed to pass in less than a week. Get the point?

Then there's the mice. A mouse - in distinction to a built in track ball within the unit itself - is attached by a wire. Another word for a wire is an antenna, and antennas are meant to amplify signals. In the case of the mouse, the wire is merely meant to carry stepped signals to the CPU; however, the shield or ground signal, especially in a battery driven laptop, is what we call floating; that is, it never really reaches ground to sink into the power company's and Mother Earth's natural ground point.

Instead it floats at some undetermined level above ground, and guess what it does? It radiates! At some undetermined level, depending upon what is stuck inside the machine and by whom.

It's no wonder that the engineers at Boeing and NASA and Apple are having such a time trying to figure out what's happening. The rules are wrong in the first place.

We live in an electromagnetic sewer, and God knows we shouldn't be playing "let's not worry about it" with computers flying planes at 37,000 feet.

The FAA knows better, and I would hazard to guess, wants to do everything within its power to avoid a panic or loss of public faith in the airline industry. That's perhaps why, they have kept it pretty quiet that they are protecting their own airport based facilities against HERF and radiated emission interference.

In a low-profile massive endeavor, the FAA is replacing the glass in its control towers and offices in and around airports.

We have received information from sources close to the FAA that their very concerned about HERF interference problems in air traffic control systems fromthe high power radar that keeps the airways safe. According to these sources, they are replacing control tower and office glass with shielded glass which attenuates electromagnetic signals by anywhere from 60-100db depending upon the severity of the problem.

The replacement program is supposed to last for several years, which coincides with the upgrading of the nations control systems - which will obviously be more automated and computer driven than ever.

If the FAA is as aware of the problem and the possibilities as it appears they are, one would hope they would take some stronger proactive measures to protect passengers - even if they're is only a glimmer of a chance that a laptop or a CD player could cause a plane to crash.

It seems entirely reasonable to suggest that the FAA should just go ahead and ban such electronic devices on planes altogether. What's the big deal? Would the traveling Road Warrior care that he would lose 5 hours of productivity on the Red Eye? Probably, but if all airlines stick to a policy (there's that word again . . . funny how it keeps cropping up) especially is mandated by the FAA, everyone would still be playing on a level playing field, and no one would lose business.

On the other hand, if planes are in fact susceptible to low level emissions from computers, is that such a good thing to openly admit? Because, what if you just turn up the volume a few db?

There are plenty of crazies out there; and with terrorist concerns on the rise, who knows what they might pull. Well, here are a couple of possibilities.

Suppose I'm a real crazy bad guy, and I bring a specially modified laptop onto an airplane. The airport security is dismal and you can get just about any electronic device through with no trouble. But this laptop is modified to emit very high levels of radiation; either automatically or upon command. If I'm real nuts, and am totally committed to my cause celebre, I might be willing to bring the plane down with me on board. More than a few people meet that criteria. It might take a little tinkering and get on the right fly-by-wire plane to do it, but with the number of events already on the books, it's doable.

Or, if my survival is important, I might check my luggage through with a HERF device, timed to 'go-off' at some point during the flight. Without me on board, of course. Luggage scanning can't tell the difference between a 'good' electronic device and a 'bad' one. If the FAA has something to worry about in this realm, this certainly qualifies.

Or, let's replace the rocket launcher at the end of the O'Hare runway scenario which was disclosed by the FBI during a CPSR meeting in Washington, D.C. on June 7, 1993, with a powerful HERF Gun. A HERF Gun is an electromagnetic generator which is focused and aimable and frequency specific. Situated in a
van, powered by a V-8 and an alternator, the HERF energy, several orders of magnitude louder than that emitted from a laptop, could have a devastating effect on planes taking off and landing.

And acquiring such devices is pretty simple. You can go out and build one -it's an exercise in Electronics 101 - or I can buy one. Where? From the US government of course. A military surplus high power radar antenna is easily modified for higher signal strength and focussed targeting by someone familiar with electronics.

Cyberspace has indeed come of age, and modern airplanes are as much a part of it as computer networks.

It's just that the FAA doesn't know what to do about it yet.

Let's hope they get up to speed quickly. Very quickly.


-- Winn Schwartau