I have seen a symbol on a IFR chart for a while and to be honest, I have no idea what it is.  If you get the SUMMA7 SID for KSEA, between the SUMMA waypoint and the BKR VOR there is a symbol that looks something like...

 

 

             106

             ___

             |

^----------------------J54---- [bKE]

         __|

         143

 

The FAA Symbol guide says it is a Changeover Point   Low/High Altitude, VOR Changeover Point giving mileage to NAVAIDS (Not Shown at Midpoint Locations).  Also there is a 16NM MEA GAP and I think I know what that means.  16NM horizontal separation between aircraft as in an area with not good communications or NAVAID signals (ie mountains).

 

Just wondering what a Changeover Point is?  Do you ever have to account for those in a FMC/CDU?

 

Thanks

The change over point is simply the point you change to the next navigational aid.  In your case, the next VOR.  These points factor in navigational aid range and, if applicable, terrain effecting the given airway.

If you use NAV radios to guide yourself, at that point you would switch your radio from VOR behind you to VOR in front of you. I think if there is no symbol, it's assumed that you should make VOR changeover at midpoint.

 

If you use FMC/GPS, just ignore that symbol.

Just wondering what a Changeover Point is?

 

It's a point at which you should (note: not must) switch from one VOR to the next.  In this case, from OLM to BKE.

 

 

Do you ever have to account for those in a FMC/CDU?

 

Nope.  It's doing the radio switching for you (and is also picking up signals from GPS, so the VORs are redundant).

 

 

16NM horizontal separation between aircraft as in an area with not good communications or NAVAID signals (ie mountains).

 

Nope.  MEA is minimum enroute altitude and has nothing to do with aircraft separation.  It's referring to the possibility that there may be a drop in your navigation signal between those two VORs.  As such, it's providing a changeover point close to where that may occur (if you look at the en route H-1 chart, you'll note there is no changeover symbol there).

<p>Wow, ok that was quick info!  I have been using SkyVector for charts and did notice the Changeover Point was not listed, but the MEA was.  All good information to know.  I think as flight simmers, we all know VFR fairly well but are a bit sketchy on IFR charts.  By chance does anyone know of a good IFR course for Flight Sim types.  I have considered the Angle of Attack courses that Rob has partnered with.  However feel I want to know a bit more before I dive into one of those.</p>

<p> </p>

<p>Thanks again for the info.</p>

It depends what exactly you are interested in: Flying techniques, flight planning, "air law"...

 

I suggest to start with pilotedge IFR workshop series:

 

 

 

I know IFR as best FS can mimic it.  However I know Microsoft never really did a good job of it and I guess I want to know how the real world does it short of buying a several thousand dollar IFR course at my local pilot shop.  I am good at letting FSBuild generate a plan for me but at times I don't feel it is even right, FlightAware is great but for US.  Maybe the Enroute rules have changed but several times I notice FSB sends me down an airway that is suppose to be one-way but they are sending me down it the wrong way.  Also just from personal observations from flights I have taken.

 

I recently "discovered" SkyVector and wanted to know how a airline dispatch office or a IFR pilot planned a route.  I can create my own route but I know countries have preferred routes so I may not be all that accurate on long international flights.  Can you tell I am really excited about the 777!  I know nobody is going to scold me for using the wrong airways on own routes, guess I am just wanting to be as real as it is in the real world.  So in reality the only area I feel my IFR skills is lacking is that of the reading maps (90% I understand, just trying to put it all together), real world routing (ties to the maps).  I am also excited to see what PFPX has to offer when it is released.

 

I will look at the pilotedge IFR workshops, maybe they have something that will give me the Ah Ha light bulb click I am needing.  Thx

 

I recently "discovered" SkyVector and wanted to know how a airline dispatch office or a IFR pilot planned a route.  I can create my own route but I know countries have preferred routes so I may not be all that accurate on long international flights.

 

Check out the links in my sig  :wink:

 

 

Maybe the Enroute rules have changed but several times I notice FSB sends me down an airway that is suppose to be one-way but they are sending me down it the wrong way.  Also just from personal observations from flights I have taken.

 

I wouldn't be surprised.  I have to applaud those in the sim community for the work they do, but there's still a large presence of misinformation and inaccurate automation out there.  I have an intense distaste for the route planners out there in the sim community because the routes they build are often nowhere near accurate (particularly where prefroutes and LOA routes come into play - around NYC especially).

 

One-way routes are one-way routes.  Granted, you're not likely to get trucked over in FSX, but in the real world, we use them for high volume routes (you'll see a ton of them up and down the east coast) and you'd get kicked over to another one if you tried to fly it in the wrong direction.

MEA minimum enroute altitude for terrian clearance, MRA minimum reception altitude for receiving navaid signal.

 

MEA minimum enroute altitude for terrian clearance, MRA minimum reception altitude for receiving navaid signal.

 

Just to be clear, MEA is not only terrain clearance:

 

"The minimum enroute altitude (MEA) is the lowest published altitude between radio fixes that assures acceptable navigational signal coverage and meets obstacle clearance requirements between those fixes."

Instrument Procedures Handbook FAA-H-8261-1A - emphasis mine

 

MOCA is only obstacle clearance (unless within 20nm of a VOR, in which case, also signal coverage)

MRA is only signal assurance

 

Gotta love the FAA, right?