MEA and MVA

[bfakes]

I'm trying to figure out those questions I missed on the SOP test and I must have missed these in my readings. Where can I find info on what these are and where they are published?

thanks

[Dan Sprouse]

The following is found in the ZOA Training/student3/mva

Minimum Vectoring Altitudes are the lowest MSL altitude at which an IFR aircraft will be vectored by a radar controller, except as otherwise authorized for radar approaches, departures, and missed approaches. The altitude meets IFR obstacle clearance criteria. It may be lower than the published MEA along an airway or J-route segment. Charts depicting minimum vectoring altitudes are normally available only to the controllers and not to pilots.

How to use MVA's

MVA data is displayed on ZOA Approach and Center sector files. This section assumes ZOA Center file version 6.6 or later.

To view MVA data...

In ASRC:

Display MVA area boundaries - Select "ARTCC LOWBND" using the MAP function from the DC rollout control.
Display MVA altitudes - Select "NDB" and "NDB FREQ" using the MAP function from the DC rollout control.
In Pro-Controller:

Display MVA area boundaries - Select "ARTCC Low Altitude Sectors" using the Radar Menu, or <ctrl><F8>.
Display MVA altitudes - Select "NDB" and "NDB FREQ" using the the Radar Menu, or <F3> and <shift><F3>.
The lowest altitude inside an area is now displayed in hundreds of feet and will have an "(M)" next to the figure to indicate this is an MVA figure. For example "31(M)" means 3100&#39; is the lowest safe altitude that may issued by ATC while the aircraft is in that region.

MVA data is difficult to map and is incomplete for all areas within ZOA. Most usable data is in the Bay Area. The staff will make efforts over time to release make more data available.

[Scott Fritz]

For the question you missed. Let look at another chart. I don&#39;t want give students who haven&#39;t taken the exam the actual answer. Go to the airport page on the ZOA website and pull up the Silent Seven SID. On the chart find REBUS. See the 6000 which is underlined at REBUS. That is a minimum altitude that an plane must cross REBAS on the SILENT SEVEN SID. Of you look between REBAS and SASSU you will see 8000 with @5100 below it. The 8000 is the recomended altitude.

The approach plates will usually have this in one corner which is the minimum safe altitude that you can fly within 25 miles of the airport.

http://www.mcm.edu/~fritzs/minsavealt.jpg

I hope this helps answer some of your questions.

[Scott Fritz]

This website does a good job of showing the symbols on the different charts. IFR Symbols (http://www.cgaux.info/g_ocx/missions/auxair/ifr_symbols.pdf)

[bfakes]

Thanks guys, it makes sense now. I found the definitions from the Student 1 menu and it&#39;s starting to fall into place. :)

[Inigo Markle-Allen]

Hey guys, let me quickly clarify some stuff here, because things are really getting confused with eachother:

MSA - Minimum Safe Altitude. It&#39;s in the bottom corner of IAPs. Notice though that the altitudes shown cover the distance from the center of the VOR all the way to 25 nm out. That means on that side of the vor that&#39;s the lowest the pilot could descend if say, they were Lost Comm.

MVA - Minimum Vectoring Altitude. This is what you&#39;re looking at on the radar screen. MVAs are the lowest altitudes a controller can descend an aircraft in that particular area, and still have the airplane 1000 feet above any obstacles or terrain. MVAs CAN BE LOWER THAN MSAs, BECAUSE THEY COVER MUCH MORE SPECIFIC AREA, AS OPPOSED TO MSAs WHICH COVER A VERY BROAD AREA.

Finally,

MEA - Minimum Enroute Altitude. This is the altitude next to the Victor and Jet airways when you display them on the scope, as well as the altitude next to various legs of instrument charts like Departure Procedures. These are the lowest a pilot can fly along that segment, and since these altitudes only extend 4nm from each side of the centerline of the airway/route segment (I&#39;m not going to confirm this in 7110.65 but if others would like to try and prove me wrong they can, I&#39;m just aware that&#39;s the legal boundry of Class E airspace around any airway). So, since that&#39;s a little 8 mile corridor, MEAs CAN BE LOWER THAN MVAs, WHICH IN MANY CASES COVER AREAS LARGER THAN THE AIRSPACE FOR THAT SEGMENT OR AIRWAY, WHICH COULD VERY WELL HAVE HIGHER TERRAIN IN THE VICINITY OF, BUT NOT INSIDE THE CLASS E AIRSPACE FOR THAT SEGMENT OR AIRWAY.

I&#39;m not yelling at anyone, the caps are just areas that really need to be UNDERSTOOD. :wacko:

- Inigo Markle-Allen