Lost Arts 1– FSS Communications.

I told you last summer that I would give the new technology an honest try and I am doing that. Here is what I’ve learned so far: Some old methods are still necessary even with the new equipment. But I’m afraid some of these methods may become Lost Arts.

I saw a flight student walking back into the airport building last week having returned from a VFR cross-country flight. He had made the flight in a new airplane equipped with the newest GPS navigation system. I asked the student, “How was your flight?” He said, “It was a great flight, no problems at all.” Then I offered the reminder that I offer all pilots after a cross-country flight, “Don’t forget to close your flight plan.” The student said, “well, I did have one problem, I could not get my flight plan activated, so I guess I don’t have one to close.” This was not my student, but my flight instructor instincts immediately kicked in, “Why couldn’t you get it opened?” I asked. “Well that’s a funny thing, this morning when I took-off, I opened my outbound flight plan with Nashville Flight Service on 122.55, but when I took off from Gatlinburg-Pigeon Forge (GKT) airport they would not answer me.

What was the problem? Why didn’t the Nashville FSS answer the student when he called to open his return flight plan? Because the Nashville FSS never heard the pilot calling. The pilot was still trying to contact the FSS on their “discreet” frequency of 122.55, but the pilot was well out of range at GKT. (A discreet frequency is used to both transmit and receive on the same frequency. Ground control, unicom, the control tower, and departure/approach control, are all examples of discreet frequencies — you use them every flight.) But in order to communicate using a discreet frequency you must be within range of the antenna that transmits and receives the signal. In other words, the antenna on your airplane and the antenna at the FSS cannot have any obstructions between them or the signal will not get through This is called “line-of-sight.

Inside Information: Due to budget cuts and some other factors, the FAA has decommissioned many Flight Service Stations around the country leaving behind the “automated” Flight Service Stations — roughly one per state. This may have been efficient use of the FAA labor force, but it left big gaps all over the country where an FSS cannot be reached using a discreet frequency.

So what fills the gaps? How do we open flight plans and get vital weather information when we are out of the “line-of-sight” range of the FSS antenna? We can use the “VOR Link.

I can guarantee you that the young student pilot I spoke to about his flight plan last week, flew his entire cross country, over and back, without ever using a VOR. He hit “GPS Direct” and a purple course line appeared on his screen that led the way. He watched the moving map pass by until his destination airport appeared on the screen before him, then he looked out the window for the real airport, and then he landed on that airport. He was unaware that he passed several VOR stations along the way because he did not need them to find his way. Imagine his surprise when I pointed out that even though the VORs may not be needed for his navigation, they could have been used to open his flight plan.

Look at the above figure and locate the Gatlinburg-Pigeon Forge (GKT) airport on this excerpt from the Atlanta Sectional chart. The Nashville FSS is not on this chart section because Nashville is over 200 miles to the west of GKT. Between GKT and Nashville there are mountains and plateaus and a good portion of the Earth’s curvature to block a radio transmission from a low-altitude airplane’s antenna. When the student attempted to call the Nashville FSS directly, the signal was blocked by the Earth and he was never heard. The direct radio call earlier than day to the FSS to open his outbound flight plan had gotten through, but that was when he was within 25 miles of the FSS antenna and had no obstructions.

What should the student have done? Look again at the above figure again. To the southwest of GKT you will see the VOR information box for the Volunteer VOR. The VOR information box has the name, the frequency, the 3-letter ID, and the Morse Code ID. But the box also has a bracket beneath it. In the bracket is the FSS name “Nashville.” This means that the Nashville FSS is the “parent” FSS of this VOR station. This tells you that there is a way to talk to the FSS even though you are too far away to transmit and receive using the discreet frequency. How do you use the VOR as a link to the FSS?

How to… First you must know how to switch the function on your on-board navigation equipment from GPS to VOR — or use the old fashion VOR that may still be sitting there in your panel. Next you dial in the VOR frequency and identify it. Selecting the “Nav” portion of the audio panel for that radio and turning up the volume allows for proper identification. You should then hear the Morse Code transmission. Now look back at the VOR information box. On top of the box you see “122.1R.” This means that the Nashville FSS can Receive your transmission through the Volunteer VOR even though you are still 200 miles away. You must now set 122.1 in one of your communications radios and you are ready to transmit out on 122.1 and receive back through the VOR on 116.4 which is the Volunteer VOR frequency.

How it works… Now look at figure 2 above to see how the reach of the FSS is extended to your airplane even though line-of-sight is out of the question. Figure 2 is a profile view (not to scale) of the situation. The airplane is shown in the far right (East) of the diagram near the GKT airport. The Nashville FSS is shown on the left (West). It is clear that the airplane is too far away and there are too many obstructions to transmit all the way to Nashville directly, but the Volunteer VOR and its Morse Code ID can be received — the VOR is less than 30 miles away with no obstructions blocking the line-of-sight. A pilot can transmit on 122.1 where the signal would be received by an antenna at the VOR station.

The pilot’s voice is then carried to Nashville on a dedicated telephone line – shown here as a dashed line. The telephone line goes up and over the mountains, through the valleys, and follows the curvature of the Earth all the way to the FSS in Nashville, where the FSS briefer hears the pilot.

The FSS briefer then responds back to the pilot in reverse. The briefer’s voice is carried on the telephone line back 200 miles to the VOR where it is then transmitted over the VOR signal. The pilot hears the FSS when the briefer “talks over the Morse Code.” The pilot does not hear the FSS on 122.1 but rather over the VOR frequency of 116.4. That is why you had to turn the VOR’s volume up — otherwise all this would happen but you still would not hear the FSS because the voice never got passed your volume control.

How you work it…

Tip 1: When addressing the FSS on the radio you never say Flight Service Station — it’s just too long. Instead you say “Radio.” The correct radio call for the Nashville Flight Service Station is “Nashville Radio.

Tip 2: The Automated Flight Service Stations monitor (are the “parent” of) many VOR stations in a geographic area. The FSS briefer will not know which VOR you are listening on unless you tell them.

Example: In this case the pilot should say, “Nashville Radio, this is N1234Alpha, listening on the Volunteer VOR.

Tip 3: If you don’t tell them where you are, they would have to make radio calls on all VORs that they monitor — and they may just give up before going through all of them. You must tell them where you’re listening.

Tip 4: Be patient when calling an FSS. These folks are not controllers. Controllers have the “press-to-talk” switch hooked on their belt and can respond to a pilot’s call almost instantly, but FSS briefers does not carry a push-to-talk switch and must walk across the room from where ever they were when you first called to get to the microphone. Give them time to get over to the mic (some are not as fast they used to be)!

Most important tip: You must activate the VOR and turn the volume up on the VOR radio. Remember you must be able to hear the VOR Morse Code in order to hear the FSS. Turning the volume up on the communications radio that you are transmitting out on will do no good.

In many locations in addition to a VOR Link, you have an RCO (Remote Communications Outlet) that can help you reach the FSS. In the area of GKT there is such a link. On the first figure there is an RCO information box shown west of GKT. The RCO is an even easier link because it is a discreet frequency — no need to switch to the VOR function. You can see that the RCO box also has a bracket below that says “Nashville.” Just dial up 122.2 or 122.3 (frequencies shown on the top of the box) and say, “Nashville Radio this is N1234Alpha, listening on the McGhee-Tyson RCO.” Your voice is transmitted through the air, but only a short distance to the nearby RCO antenna and again your voice is carried to Nashville on the telephone. The FSS contacts you back by the reverse course and you receive the response back on the same frequency.

THE BOTTOM LINE: If you face threatening or deteriorating weather, contacting the FSS to get up to the minute weather information greatly increases the chances of making the safest in-flight decisions. But you can’t get the information without using a “Lost Art” that is still relevant today despite technology advances. The fact that the student did not know how to reach the FSS to activate his flight plan was only part of the problem. If he could not contact FSS to start the flight plan; that also meant the he could not have contacted FSS for even more vital information.