A Graphic Test

I just finished reading David Evans’ column "It Ought to be in Pictures" (September 2000). I put Flight Lt. Mark Walmsley’s basic question, "Do graphic displays offer a cognitive advantage over alphanumeric presentation of the same information?" to a test.

My nephew, a high school freshman, was chosen for this test. His only real aviation experience entails the 20-odd flights in the copilot’s seat of a Ce-501 with me. (The truth be told, he has been taught proper check-list usage, IFR approach briefings, the programming procedures for the A/P, GPS, Loran, nav and com radios.) His total experience in aircraft is about 40 hours, riding in the cockpit of a small business jet over this past summer. He has zero hours of flight instruction towards a pilot certificate.

My nephew was familiar with most of the terms used on the alphanumeric display. The few that he wasn’t completely familiar with were explained. We went over the alphanumeric displays with the text hidden. It took about 20 minutes of concentrated work for him to deliver the aircraft profile and parameters of control correctly. When the page was turned (text still hidden) to the graphic displays, he read the aircraft profiles and parameters of control correctly on six different displays in less than four minutes the first time.

The real surprise was that he then asked me what the different color presentations indicated (manual flight, normal A/P, high order automatic control), so without any coaching from me, he knew that the colors had some meaning and importance. This gave me an immediate answer to Lt. Walmsley’s question.

I was called to the hangar floor for about an hour. By the time I got back, my nephew had commandeered one of my high-end computers/color scanners/color printers and one of my office hands. During that hour, they had downloaded Walmsley’s two files, scanned the graphics from your Avionics Magazine column and done the enlargement necessary to use the graphics and text for visual aids for my nephew’s speech for a class the following Thursday.

All told, I figure my little test of the differences in interpretation of the displays cost me $300 in computer time, lost time of office personnel, and graphics paper and other supplies. You probably won’t receive many thank you letters from companies that you have cost money. However, you did myself and many others a much greater service; your column lit the fires of imagination in a 15-year-old boy. You also may have reached other students in his speech class and opened their eyes to what aviation holds for the future. Please continue doing what you have done. From myself, my company and the rest of the aviation community, thank you.

Kyle Goebel
F.A.S. Aircraft

Pushing Development
Just read your Editor’s Note in the July issue (page 4) entitled "Aircraft for Everyone." I am creating a nonprofit organization, Skyaid, to save 100,000 lives per year, which will be using "aircraft for everyone."

I realize that conventional wisdom says that new aircraft designs will not be available for 20 to 25 years. The Skyaid organization will be pushing the technology development so as to save lives with new aircraft by 2005.

By the way, I have been on the technical advisory board for Moller International for most of the past decade, while working at Boeing.

Our Website, www.skyaid.org, has lots of details.

Henry Lahore

A visit to the Skyaid Website indicates that the organization was set up to develop "rapid emergency response," primarily for victims of heart attacks, strokes, fires and accidents. Moller International is a California-based company that developed a concept for a personalized air vehicle. –Editor

In our November issue, we inadvertently let an "h" slip into Paul Dillon’s name. He is executive vice president of VXI Technology. Also, in our October issue, we referred to East Coast Avionics as East Coast Aviation. We regret the errors.

A Cocktail of Frequencies
David Jensen’s article (August 2000) is correct when he discusses the menace of personal electronic devices (PEDs). But the problem is many times more severe than generally supposed.

Measurements made with a single source device are interesting but do not explore the effect of multiple devices. The problem is that different devices radiate at different frequencies, and the aircraft’s systems are subjected to multifrequency attack.

The result is that sum and difference frequency components are then generated. Even two apparently identical devices will differ, and the difference frequency is produced, along with all of its harmonics. The result is that not only do multiple sources create more interference (EMI), but they create new kinds of interference that a single source cannot create. My experience indicates that even DO-160D is lenient by at least 20 to 30dB.

An interesting side fact is that in every case of EMI that I have investigated, the actual path of the interference involved radiation from the hull of the aircraft to the radio antenna...never into the wiring.

One development that has raised the level of risk is the widespread use of high speed HCMOS technology. The way HCMOS devices get their speed is by having very high current sinking and sourcing capability, which can charge or discharge incidental capacitance very quickly, creating very short, high amplitude current pulses. I would estimate that a typical laptop will radiate several watts of RF (radio frequency) on a cocktail of frequencies.

Paul Simison
Hickling, Norfolk, England

A Suggestion
I’ve been reading your magazine for about one year. Usually I read it from cover to cover, and some articles are quite useful for me to keep pace with avionics news.

But let me say one thing regarding your presentation. Maybe I’m wrong, but I think that it would be great if you would dedicate one page (a couple of articles) to the avionics systems principles. It is useful to compare some existing system with a coming new alternative system. You do not need to describe where the electrons are running, but provide the main differences and advantages.

This question was raised for me when I read about the fiber-optic gyro. I work for RJ70 AVRO aircraft. This aircraft uses laser gyros in the inertial reference system. With that type of gyro, I am familiar enough. But is it possible to explain a bit the basic principles of fiber-optic gyro?

Anyway, thank you for your interesting magazine.

Stanislav Lobashov
Engineer Avionics
AirBaltic Corp.

An Errant "S"
On page 31 of the subject article, Lockheed Martin Federal Systems is mentioned as being in Oswego, N.Y. We are actually in Owego, N.Y., a different city from Oswego, which is located north of Syracuse.

Also note that our official site name has been changed to Lockheed Martin Systems Integration-Owego.

Ron Fish
Manager, Processor Subsystems Business Development
Aerospace Systems
Lockheed Martin Systems Integration-Owego, N.Y.

Having lived in Syracuse, I should have known the difference. Oswego is north, while Owego is south of Syracuse. Thanks for bringing this to our attention.–Editor

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