To be perfectly honest, we really did not know just how much interest there was in the Next Generation Air Transportation System (NextGen), nor did we have any preconceptions as to what to expect at the show.
I would have to say we were pleasantly surprised at the turnout.
We pretty much filled the room for two forums and, man, did we have fun — not only with a bunch of laughs, but also some interesting discussion about ADS-B.
The folks attending the forums were great and the questions were good. However, many of the questions I received while at the show and later via email made me realize that many people are not reading this series or I am not getting across the fundamentals of the systems.
We received about 20 direct mail responses about the show, followed by more questions. I decided to share one of the questions here so, hopefully, everyone can learn a little bit more about NextGen.
A Cub owner asks: How would a non-powered aircraft be able to fly within the new proposed airspace with ADS-B?
Kudos to the person who asked this question — it’s a good one. I could be a wise guy and just tell you to prop over the plane, get in, and go. But I won’t go that way, of course.
What this person was alluding to was the lack of power and not being able to power up a Universal Access Transceiver (UAT). His little Cub is already challenged with a crude battery device already. How is he going to be able to power up a UAT and some kind of transponder from the same supply?
This is a great question because it has many potential side effects that many aviators do not take into consideration.
I would have to assume he is either using the internal battery for each device or he has rigged up some king of external 12-volt device to power both the Icom and GPS. Many have done this in order to incorporate a cigarette lighter auto adaptor that comes standard with many GPS devices. However, if using the standard batteries that typically come with some portable GPS and radios, the probability of sharing either of these supplies would definitely not be a good idea. So far we have not seen any self-powered UATs on the market, so you would have to resort to using the external sources we mentioned earlier.
Just beware that most portable radios do not necessarily run on 12 volts. Special precautions should also be taken by triple checking the polarity of the supply before you connect it to your device. I know it sounds silly to some, but I just cannot tell you how many people screw this up and kill their devices in doing so. You should also protect these lines with fuses. That’s another one we see often. This should also be checked before connecting all four devices up to one common 12-volt source.
When doing this you should keep in mind the amount of current being pulled from the battery will increase. It would be wise to estimate the amount of current each device is pulling and add them up. A good rule of thumb is to have twice the current available for the amount of current consumption. This also means that the wire being used would have to increase in gauge to satisfy the current requirements of the system.
You should also be aware any noise in the system’s DC component would increase proportionally with the current. This can be measured with a relatively inexpensive oscilloscope if you just happen to have one available. Bandwidth is not very critical; 100Mhz would be more than sufficient to get the job done. It if proves that there is a substantial amount of noise on the line, you may need to add some filtering.
My guess is in the not-too-distant future, we will see more and more UATs coming in that operate with some internal battery specifically for non-powered aircraft.This is the latest in a series of articles looking at the impact of the Next Generation Air Transportation System (NextGen) on GA pilots.