Can anybody verify for me if I am correct. Eastbound traffic cruises at odd levels and Westbound traffic cruises at even levels. Southbound traffic cruises even levels and Northbound traffic stays at odd levels. Also, if this is correct does it apply to just the continental US or is it worldwide> Thanking you all in advance.

“East is least”…

001-180 degrees uses odd

181-360 degrees uses even

unless they’re VFR (below flight levels -18,000)- Then its odd or even +500ft. Ex: Flying heading 001-180= 3,500, 5,500, 7,500, 9,500… heading 181-360= 2,500, 4,500, 6,500, 8,500, 10.5…

Flight level rules are slightly different depending on RVSM (reduced vertical seperation minima) equipped or not. FL290- 410 is RVSM airspace. Equipped aircraft can have 1,000ft vertical seperation instead of 2,000 as it used to be. There is a little more to it but that’s the simple answer…

For VFR aircraft those odd + 500 (easterly) or even + 500 (westerly) are only valid for aircraft more than 3000’ above ground level. So over tall mountains, they are often not used.

OK, that one I don’t get in this context. The way I used to teach it is 0-179 is the first half of the compass rose, an ODD number.

Someone left the red port wine out, etc…

As long as you are below class A and in above class G airspace, VFR altitudes apply based on the cardinal magnetic heading.

Do you have a FAR that supports your statement above?

Remember altitudes are NOT based on AGL, but MSL.

There is nothing that says I can’t fly 7500 over a 5000 tall mountain and maintain VFR. Smart, maybe not, but AGL has nothing to do with VFR or IFR flight levels.


I have been taught east is least. Generally, lowest VFR altitude is 3500 going east, and 4500 going west. So, east is least in this context of things.

See FAR 91.159 at for VFR cruising altitudes.

Clear as mud now? :slight_smile:


Perhaps this will help refresh your memory from ground school. Check the table at 3-1-5.
AIM Chapter 3

Duhhhhh Thanks! :smiley: Even found the error of my ways in the FARS provided above.

Guess I fly as high as possible so I don’t think about AGL except for obstacal clearances, and since I generally fly IFR, MEA, MOCA and all that alphabet comes to mind.

Never have done any “serious” mountain flying, that’s for sure.


Like the man said, FAR 91-159: Except while holding in a holding pattern of 2 minutes or less, or while turning, each person operating an aircraft under VFR in level cruising flight more than 3,000 feet above the surface shall maintain the appropriate altitude or flight level prescribed below, unless otherwise authorized by ATC.

The way I was taught to remember it is odd birds fly east.