This has probably been addressed, but I wasnt sure how to search for this.

There have been a few guys at our field say "something is just crashing thier planes". They feel someone has a a way to grab their frequency and knock their plane down. I figure this is a common occurance, but they are afraid to fly. It doesnt bother me other than i have to hear about it and they want me to fix it, since I am the club pres. I also asked our nieghboring clubs about 30 miles east and west. They say the same thing happens at thier club every 3-5 years. One guy it happened to was a really good pilot, and he lost his 30% YAK, However he was flat spinning when it crashed. The other flies strickly electric and hitec, fair pilot. The main crasher uses used junk, and was asking for it, should be on a buddy box, but is hard headed.

We used AMA frequency checker about 2-3 years ago, and nothing was found. We also have a Hobbico freqency checker at our field. Anyone have a solution for this problem? Thanks Dylan F.

In the vast majority of cases Dylan its like looking for non existant ghosts. Many folks cannot face the fact that they scrwed up and will always look for the easy excuse. Its a common natural reaction.

Yes someone deliberatly shooting down aircraft can and has happened in some well documented cases, at least one well known from about twenty years ago in Los Angeles resulted in jail time for the perpertrator.

The point is its extremely rare but yet every field seems to have rumors of a mystery bomber.


Also on strickly a local basis it is common for some channels to actually suffer from interferance, In many cases this is from legal industrial users that are between each of the Rc channels. These users are officially 'primary' users and we are officially 'secondary' users which mean is there is a conflict we must cease and desist. Local channels that may have this problem are however easily identifiable in most cases.

So I suspect most of your local problem is in fact the result of human nature. It gets kinda funny at times when watching a crash that is very obviously a problem with the pilot and nothing else. This indivudual will immediately complain of radio interferrance to everyone in earshot and then pretty soon everyone in earshot is chiming in with mystery crashs on such and such a channel. Pretty soon the 'Mystery Bomber' becomes the scapegoat and everyone feels better.

John

I would agree with Johnbuckner on this one.

Even very good pilots and careful builders can have an ocasional problem that looks like a radio interference problem.
If you look in my gallery you can see that I fly a broad range of airplanes. I am considered a better than average pilot even at 64 years of age. I test fly and instruct on a regular basis but in the last year I have flat spun one aircraft to the ground and put in a 35%extra of mine due to what looked like radio failure.
The aircraft that I spun in was from altitude in an upright spin that went flat to the point that it was unresponsive to any control movement and was witnessed by a fellow pilot standing beside me. It wasn't radio or mechanical but a cg situation coupled with a too small vertical fin and the ability of the wing to blank out the entire tailgroup in certain flight regimens.

The Extra showed normal voltage on all of the onboard voltage indicators two minutes before takeoff.
The takeoff was a normal rolling turn into 3 consecutive loops but the rudder started wagging to full deflection each way at the bottom of the third loop. I throttled back and came around in the pattern for an immediate landing only to have the airplane appear to go into failsafe as I was turning final. From there it made a wide circle and went down thru the edge of a tree.

Bottom line was that the servo battery which is independent of the receiver and runs thru a voltage regulator on a safety switch was discharged to the practically nothing.
How did this happen on a plane that had been flown for 6 years? I hooked it on a Minron charger that I had handy in the garage instead of the one that it normally uses in the hanger. The settings on the charger were wrong and I cycled the battery rather than charging it. Several things on my part could have prevented this but again it looked like a radio failure when it was a mistake strictly on my part.
My reputation is good enough that I could have claimed radio or mechanical problems and no one would have been the wiser. A lot of Goblins and Gremlins get blamed for radio problems while they in reality are busy finding other very creative ways to help the pilot reintroduce his airplane to the earth.

My all time favorite rationalization that I actually heard used some years back was "It was solar flairs"

Of course no one else was affected by the 'Flairs' including myself on the same channel 72.40 Orange/White.

The golden age of creative rationalizations was when most all radios were AM units and more seriously affected by something called third order intermodualtion. An effect where someone about ten channels away or in that area would indeed cause problems.

John

I never have experienced nor witnessed loss of control due to radio interference and never will. At least not since I read the AMA insurance policy and learned that liability that arises from interference is excluded from coverage.

Abel

Are you kidding????????? Where can I find that?

AMA doc 500-1, Exclusion T. on p.13

Thanks Abel......That's something to think about.

what have you changed so that you won't experience interference?

As was stated most of the time it is dumb thumbs that should be blamed for crashes, but there are rare occassions of actual radio interference, we had a situation a few years back where an oil rig was placed next to our field, the systems that they were using caused 4 planes to go in on one day after the 4th plane went in we got a freq. scanner out and found that there was major interference across the range of channels.

Attitude

I have witnessed radio intereference, and when it happened, it was obvious that it happened. During a contest, one experienced participant was flying without having the channel pin. A beginner contestant was preparing for flight, had the pin, and turned on his radio. The result was immediate and fatal to the experienced contestants plane.

On a second occassion a few weeks ago, I was flying my CAP 232, and was making a slow downwind leg to set up for an approach. Iwent to bank the plane right, and it banked left. I immediately called out "Radio Hit", chopped the throttle, and the plane nosed in from about 100 feet. As I continued to replay the incident in my mind over the next week, I realized that the problem was actually a stall induced by wind shear (also known as a gust of wind from the tail). In the few seconds, I had to react, I reacted improperly. What looked like radio intereference was actually pilot error.

Brad

Bkdavy,

You have missed abel_pranger's quick wit. However, there is definitely something to say for his point of view.

When I give my next program at the club meeting, I will include his info about the folly of crying wolf, I mean interference.

It is good to read the instructions. Problem is, the instructions are all over the place.

Ken, AMA 19352

One common problem is people who check their equipment before leaving home and leaving their transmitter on. I have seen several cases where someone "lose's it" just as someone is parking right across from them. Of course no one admits to leaving the transmitter on.

Ok I have seen rf issues. We have high voltage power lines within 1/2 mile of the field. The insulators were arcing over generating rf and causing crashes on good equipment. After the power co. use a helo to hover clean the insualtors with a really gutsy guy on the skids, the problem went away. You can have interferrance, and you may or may not crash. Ya'll have a nice day.. Jim

If the interference happens low to the ground, like on final approach and maybe 15 feet high or lower and the interference always happens in the very same spot, it could be coming from the ground.
Oil companies actually can find oil by detecting magnetic anomalies. I have flown at two sites that have these anomalies present. They may seem to be seasonal and they may diminish for several years and then re-appear.
The real signature of this type of interference is the airplane is hit momentarily at low altitudes and over the very same spot. If you are experiencing interference at higher altitudes, then this is not the source.

Here, in Houston, one of the clubs was experiencing interference . It was tracked to a radio station's antenna. They claimed that they had no equipment capable of omitting a signal on RC frequencies. But it turned out that improperly ground equipment was causing the tower to transmit on frequencies other than it was assigned.