91.177

A

azaviator08

New Member
If you wanted to fly IFR gps direct can you stay at the OROCA rather than the MEA or MOCA? Let's say you were flying gps waypoint to gps waypoint in higher terrain and you needed to stay lower for oxygen requirements.

91.177 - Can anyone clarify this FAR for me? Is it saying you have to fly MEA or MOCA (within 22nm)? But if one isn't published for a route you should stay 2,000 feet above in mountainous and 1,000 in other. When would there be a case where an MEA isn't publised?

Let's say you were using a gps to navigate instead of a VOR. Could you fly at the MOCA beyond 22nm? I would say no b/c of 91.177 and probably in case your gps became unreliable you would have no other means of navigation.

I hope this makes sense.
 
If you're flying an aircraft, that isn't equipped with supplemental oxygen over mountainous terrain, it's best just to stick to victor airways even if you are operating with IFR GPS enroute capabilities. Most OROCA out west can get pretty high, usually higher than the actual MEAs in the area.
 
The MEA and MOCA is utilized when you are on a published airway. So it applies when you are on the airway (with 4 nm either side). When you are not on the airway (i.e. flying direct) the OROCA takes over as your minimum approved IFR altitude. Remember what the MEA gives you...obstruction clearance and acceptable navigation signal coverage. Well, the OROCA gives you obstruction clearance and acceptable navigation signal coverage goes out the window because you are using GPS to navigate. So to answer your question, when flying GPS direct ,off airway, the OROCA would be your minimum approved IFR altitude.
 
I agree with MedicRyan, also what if you were to loose RAIM, you would need to climb to the OROCA.
 
fosters said:
If you're flying an aircraft, that isn't equipped with supplemental oxygen over mountainous terrain, it's best just to stick to victor airways even if you are operating with IFR GPS enroute capabilities. Most OROCA out west can get pretty high, usually higher than the actual MEAs in the area.
Click to expand...
That. In fact, looking at the Low enroute that covers the northern half of NM, the OROCA along V62-263 just west of SAF
(MEA 9000) is 13,900.
 
A150K said:
That. In fact, looking at the Low enroute that covers the northern half of NM, the OROCA along V62-263 just west of SAF
(MEA 9000) is 13,900.
Click to expand...

Or V-whatever-it-is (25? 23?) between RZS and GVO. MEA is something like 6,400. OROCA is 11,300*. Which is not a small number for most training airplanes.

* Quoting from memory/recent experience, appropriate chart not in front of me.
 
Autothrust Blue said:
Or V-whatever-it-is (25? 23?) between RZS and GVO. MEA is something like 6,400. OROCA is 11,300*. Which is not a small number for most training airplanes.

* Quoting from memory/recent experience, appropriate chart not in front of me.
Click to expand...

A good number of MEA's in my area are >=11,000. With OROCAS well in the 13's and 14's, most people stick to airways North and West of ABQ. Now going direct Roswell--usually not an issue.
 
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