When can ATC assign you below the MEA?

M

meritflyer

Well-Known Member
Often, ATC assigns planes altitudes below the MEA (withstanding the MOCA and the 22 NM rule).

Is there a criteria for when ATC can do this? It always makes me query such altitudes as a possible mistake but every time, it's met with an "affirmative".
 
I believe they have MVAs, minimum vectoring altitudes, which are charted somewhere in their magic caves?
 
Aproach control have MVA charts that they use to vector aircraft under radar control. As far as I know these MVA charts are only available to controllers. MVA altitudes will be lower than MEA's and MOCA's. Any contollers on this blog with more insight?
 
V2+10 said:
Aproach control have MVA charts that they use to vector aircraft under radar control. As far as I know these MVA charts are only available to controllers. MVA altitudes will be lower than MEA's and MOCA's. Any contollers on this blog with more insight?
Click to expand...
Not a controller, but the first page on this pdf shows the Detroit mva chart: http://www.zobartcc.org/include/viewfile.php?action=view&ID=184

and here's a pretty decent article about them: http://www.flightsafety.org/fsd/fsd_sept04.pdf
 
We were practicing holding at LEADS on this approach: http://204.108.4.16/d-tpp/0904/00446IL20.PDF

The controller told us to go direct to LEADS and report established in the hold, maintain 3000. I asked him if that was ok since the published MHA is 3500. He said the MVA for that area is 3000. But I wondered about it because when we're holding, we are not being vectored.

Any ideas or comments?
 
MEA (minimum enroute alt) is an alt an air route that ensures terrain obstruction, radio and radar coverage through out entire route.

MOCA (minimum obstruction clearance alt) pretty much like it sounds. an alt on an air route that ensures obstruction clearance only.

MVA (minimum vectoring altitude) lowest altitude that a controller can issue vectors to an aircraft. To an approach control this is the lowest altitude (for the most part) that the controller will have aircraft fly.

MEA and MOCA are for air routes only for enroute portion of flight.

The controller may also use other things to issue safe altitudes for instance: I worked approach control in to CKN airport in Minnesota and on the VOR RY 31 Approach there is an initial approach fix called FRUGS with a crossing alt and published holding of 2700. The MVA in that area was 2800 we could have the aircraft in holding at 2700 ft because it is published on the approach plate at 2700 even though it was below our MVA. Now if that aircraft wanted to RTB to GFK we would have to climb them in the hold to at least 2800 before we could vector. This specific scenario only happend if the pilot did the published missed for the vor 31 approach.

http://www.naco.faa.gov/d-tpp/0905/05682V31.PDF

Anyway approach controls will probobly use MVA more than anything else.


hope this helps a bit

AW
 
you can assign an altitude below the MEA, when you have a MIA (minimum IFR altitude/en route) chart or a MVA (minimum vectoring altitude/tracon) chart for the area. all centers and approach controls have this chart readily accesible while working position. there are MANY instances where the MEA is much higher than the MIA/MVA.

if the center/approach controller has reasonable assurance that they will maintain radar contact with the aircraft, you can use the lower MIA/MVA altitudes. the stipulation is that you need to keep the aircraft on radar. if you think you will lose them, you need to keep the aircraft on the MEA.

the reason MEA's are so much higher is because they guarantee navigational signal coverage along with terrain and obstruction clearance.
 
There are rental/training aircraft that have IFR GPS's these days?! Someone better let the FBO I work for know...most of ours are still /A only.
 
meritflyer said:
Often, ATC assigns planes altitudes below the MEA (withstanding the MOCA and the 22 NM rule).

Is there a criteria for when ATC can do this? It always makes me query such altitudes as a possible mistake but every time, it's met with an "affirmative".
Click to expand...

If you are a helicopter or VFR aircraft not being vectored. Those are some other cases.
 
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