| Flight Plan Problem Solving / Rose Marie Kern |
How many times have you filed a flight plan – with either the Direct Access User Terminal System (DUATS) or Automated Flight Service (AFSS) and when you attempt to get your clearance or activate the plan – it just isn’t there? This is a situation that is highly annoying not just to the pilot, but to ATC people as well.
Discounting human error, there are actually a number of reasons why a flight plan may be missing when you attempt to retrieve it. We will look over each of these and hopefully it will help to reduce the incidence of this happening.
The first thing to remember is that whenever you file a flight plan, it stays in the computer data banks of the company you filed it with until half an hour prior to flight time – then it transmits to the computer of the service provider, ARTCC or Flight Service, with whom you will activate.
Say you filed IFR with DUATS, an hour prior to your proposed departure time the Center (ARTCC) or Tower will receive the flight plan – no earlier. If you call for clearance too early, or if your ZULU calculation was off, the flight plan will not be there. Flight Service receives VFR plans filed with DUATS an hour prior to the proposed time as well.
Flight Service will never see that IFR flight plan at all. If you call an AFSS and ask them to change your proposed time or some other element, they do not have any access to a flight plan filed with DUATS. The best they can do is help you quickly re-file.
One of the primary advantages of the new FS21 computer is that if you have filed a flight plan with any AFSS, all the other AFSSs will be able to pull up the data. Flight Service can make direct changes to VFR flight plans right up until the time they are activated, and they can make changes to IFR flight plans up to an hour in advance of the proposed time – after that the flight plan transmits to ARTCC and Flight service no longer has control over it.
If you attempt to get an IFR clearance and the tower says the flight plan is not there, then call up the nearest Flight Service right away and see if perhaps it was accidentally filed as VFR. Changing it to IFR is a quick and easy fix.
Correctly converting to Zulu time is one of the biggest recurring problems. When I am speaking to pilots, I try to make sure that the time they give me is correct. Frequently a pilot gives me local time thinking I should automatically know what he means. Normally I will come back with something like “You mean tomorrow morning?” or “That’s two hours from now right?” just to make sure that we are on the same wavelength.
Another major problem we have when it comes to IFR flight plans has to do with the way routes are filed. With the advent of GPS, a lot of pilots want to fly direct from departure to destination – and as long as those two points are within 300 miles of each other it mostly works. The Flight Service computers “know” where any fix in the country is, but the ARTCC computers do not.
ARTCC computers operate independently of each other – only meshing at the boundaries to the next ARTCC over. They know all the fixes and small airports in their own airspace plus about 200 miles outside their airspace. They also know all the major airports across the country.
ARTCC computers do not know where all the small airports or intersections or other fixes may be outside their designated airspace. Thus, if you have filed a flight plan with DUATS or Flight Service and it is a direct flight – the DUATS and FS21 computers will accept the flight plan, hold it until it is time to transmit to ARTCC, then transmit. At that point the ARTCC computer may reject the flight plan because the routing is not recognized.
This puts the flight plan into limbo. If it is kicked back to the AFSS, the flight data specialist may try to call the pilot with the phone number on the flight plan, or he may try to fix it and put FRC (Full Route Clearance) in remarks so than the person giving the clearance understands they are not to simply say “as filed”.
Now when the pilot calls for clearance, he is forced to switch to an AFSS frequency to refile.
One of the ways of getting around this problem is to give the computer what it wants. Say you are traveling from El Paso to tiny little Eagle Creek airport in Indiana. Knowing that the Albuquerque Center computer may not know Eagle Creek Airport exists you can do one of three things.
Center’s computer only “worries” about the first fix past its own airspace – once it recognizes that point, it will accept the rest of the routing. So, you can choose to file to a point just outside the Center boundaries and thence direct to your destination. An example would be from El Paso to Lubbock to Eagle Creek.
Another option is to file for a large, well known airport near to your destination – such as Indianapolis, and from there to Eagle Creek.
The third method of circumventing this problem is to simply file from your departure point to the latitude/longitude of your destination and from there to the destination. The Center computer always takes lat/longs.
Once you have “fooled” the computer and are airborne, you can ask the Center controller for Direct to your destination and he can manually override it as he changes your clearance.
Flight plans seem like simple things, but computers are basically stupid – you have to spell everything out for them in a way they will understand. Hopefully this insight will help you in your next flight plan debacle or better yet avoid it from happening.
Rose Marie Kern works at Lockheed Martin’s ABQ AFSS. If you’d like to ask Rose a question send her an email at author@rosemariekern.com
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