Even flight levels above FL400

coa787

Unknown Member
Wow. I must be really stupid because I still don't get it. All that article said was that RVSM is used between FL290 and FL410 and that separation was reduced from 2000' to 1000' because 2000' separation was "too cautious."
 

NJA_Capt

Well-Known Member
I still don't get it. All that article said was that RVSM is used between FL290 and FL410 and that separation was reduced from 2000' to 1000' because 2000' separation was "too cautious."
Because separation above FL410 is 2000'. So the altitudes are FL410, 430, 450, 470, 490, 510.
 

SteveC

Really?
Staff member
"Historically, standard vertical separation was 1,000 feet from the surface to FL290, 2,000 feet from FL290 to FL410 and 4,000 feet above this. This was because the accuracy of the pressure altimeter used in aircraft to determine level decreases with height."

I was trying to point out the reason for the increased vertical seperation at higher altitudes - reduced accuracy of barometric devices at low air pressures (i.e. high altitudes). RVSM was implemented when it was determined that, with the proper equipment and training, it was acceptably safe to have aircraft pass within 1,000 feet of each other at these rarified levels.

Above FL410 the altitudes are at 2,000 foot intervals instead of 1,000, ostensibily for the same reason. (I don't know if the reduced amount of traffic above FL410 played into the decision at all or not.) The valid flight levels are: ...FL390(eastbound), FL400(westbound), FL410(eastbound), FL430(westbound), FL450(eastbound)...
 

goindownthepipes

Well-Known Member
If one REALLY wanted to fly at an even flight level above FL410 they actually could...BUT one would have to ask for a block altitude assignment from ATC to operate between FL410 and FL430 and get that block approved. This occasionally happened in my area of ZJX where a pilot wanted to go higher for chop, but couldn't due to weight and could only make FL420. It's not a usuable flight level as far as ATC is concerned, but thats how you would go about being able to fly there if you really wanted to.
 
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