Minimum Enroute Altitudes

[Guest meyomyx]

Could someone explain MEA's?Specifically, when a route on a STAR includes a leg with a MEA of say 6000 but where the navaid/fix that ends the leg requires an altitude of 4000 as an IAP, at what altitude should the leg be flown?Cheers :-)

[michal 44]

MEA - minimum enroute altitude. It usually assures terrain clearance.So in your case you fly the leg at 6000 (or higher) and then descend to 4000 to satisfy the IAP crossing restriction.Michael J.WinXP-Home SP2,AMD64 3500+,Abit AV8,Radeon X800Pro,36GB Raptor,1GB PC3200,Audigy 2

[Guest meyomyx]

Descend below 6000 to arrive at 4000? Thus descending below the MEA for that leg?

[michal 44]

>Descend below 6000 to arrive at 4000? Thus descending below>the MEA for that leg?Notice word "enroute" in the definition of MEA. It applies to enroute portion **only**. Landing/approach restrictions take precedence.Michael J.WinXP-Home SP2,AMD64 3500+,Abit AV8,Radeon X800Pro,36GB Raptor,1GB PC3200,Audigy 2

[Peter Clark 21]

>Notice word "enroute" in the definition of MEA. It applies to>enroute portion **only**. Landing/approach restrictions take >precedence.MEAs can be applied to the enroute (airway) structure, or to segments of an approach. Just because it's on a STAR or IAP doesn't change the term - it's still the minimum enroute altitude while you're on that segment. It's only after the FAF that it becomes an MDA or DH depending on the type of approach.>Specifically, when a route on a STAR includes a leg with a MEA of >say 6000 but where the navaid/fix that ends the leg requires an >altitude of 4000 as an IAP, at what altitude should the leg be >flown?Segments must be flown at/above the listed altitude for that segment. So if on your IAP you have fix B, C, and D and the route looks like B 4000 C 3000 D 2000 FAF you are required to stay at/above 4000 until reaching C. Descent to 3000 cannot be started until passing fix/navaid/waypoint/whateveritis C. Same with the descent to 2000 - cannot start the descent until after D.If your STAR feeds from a fix A to the IAP fix B at 6000 - you stay at 6000 until crossing B and then descend to 4000. Even though the plate lists the IAF (:( segment 4000 to C, you cannot descend to 4000 until you've passed point B, exiting the STAR and joined the IAP.I tend to work better with actuals rather than hypotheticals, what's the STAR and IAP in question?Luck.

[michal 44]

Peter is obviously correct. Technically the enroute portion of the flight ends with IAP so you must maintain MEA (or above) before reaching the IAP. After crossing the IAP you may desend to whatever the next published altitude is.Michael J.WinXP-Home SP2,AMD64 3500+,Abit AV8,Radeon X800Pro,36GB Raptor,1GB PC3200,Audigy 2

[Guest meyomyx]

Specifically, the MEA's from the West into Salzburg (LOWS)(Traun/Chiem) are 6000 and meet at the SBG VOR, which is the IAP for 16 ILS at 4000. Admittedly there is a racetrack at SBG with a minimum altitude of 4000.SOWhen approaching from the West, would one fly at 6000 until overhead SBG and descend to 4000 in the racetrack before commencing the approach? So all flights arriving from the West need a hold?

[Peter Clark 21]

> When approaching from the West, would one fly at 6000 until> overhead SBG and descend to 4000 in the racetrack before > commencing the approach? I don't have real charts for this airport, but the Vatsim charts for the airport depict three feeder routes from the west on this arrival, MUN, TRAUN, and RTT. The route segments have descending MEA's, and all of them have a stepdown fix at 4DME SBG to a lower MEA of 4000, so (according to this chart) you would get down to 6000 feet as appropriate on the chart (after MUN, TRAUN, or D12 SBG), and then descend to 4000 feet within 4NM of SBG, and after that follow the 178 radial coming out of the VOR and subsequently intercept the LOC/glideslope as depicted on the ILS 16 chart. Does the real chart not have the stepdown un-named fix before SBG?> So all flights arriving from the West need a hold?Again, I don't have the real charts for this, and the Vatsim charts do depict a hold at the SBG VOR, however it's a thin-line hold. Thin-line holding patterns on IAP charts are only used for missed approaches, so you wouldn't go into the hold on this approach unless you had gone missed. Of course, in a non-radar environment you might get assigned a hold at that VOR by ATC because when you got there someone else was already shooting the approach and hadn't landed and closed their IFR flight plan yet, and that ATC-assigned hold might have the same instructions ("Hold northeast on the 358 degree radial, left turns") as the printed hold, but you're not required/expected/wanted to go into a holding pattern during an approach unless it's a thick-lined hold-in-lieu of a procedure turn (which can also be used as a missed approach hold if they want, but not the other way around). The people who design the approach will generally give you enough room to descend to the next altitude after crossing the fix, and if they can't then they'll put in a procedure turn, or hold-in-lieu (which of these they use depends on obstructions in the area, and how much airspace they have to play with - a hold instead of a procedure turn takes up much less horizontal airspace, generally they're used when other airports traffic or terrain means they need to keep people confined) for you to use to drop the altitude before going on to the next segment of the approach. Course, without a procedure turn or hold-in-lieu depicted you're out of luck without radar vectors on this approach if you're coming in from the RASTA transition (south-east). I'd probably do a parallel entry hold as depicted to get back around, if there's a holding pattern there (regardless of what it's supposed to be used for) it ensures that someone has gone through the analysis of the area for obsticles and has determined it clear enough to support a hold. Nothing worse than being non-radar in IMC attempting to build your own procedure....

[Guest meyomyx]

Thank you for your detailed and considered reply Peter.I don't have a chart that shows 4DME from SBG ....... which probably explains my confusion. Just off to find one.Flying from LOWS to LDSP (or LDDU) is a good trip over good scenery so used to the RASTA SID and STAR. I do as you suggest on the return - fly into the hold at SBG and shoot the approach from there.The SIDS for LOWS are fun to flyThanks again