wardialer
Topic Author
Posts: 1205
Joined: Fri Sep 14, 2001 1:08 pm

No EVEN Number Altitudes above FL400?

Thu May 16, 2019 7:15 am

I monitor flight tracking web pages most of the time and I notice that there are no flights that are at EVEN number altitudes above FL400 such as FL420, FL440, FL460. My question is, how come pilots don't choose these EVEN numbers as mentioned above when cruising at altitudes above FL400?
FL400 seems to be the only EVEN number used, but no ODD numbers above that.
 
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Starlionblue
Posts: 19343
Joined: Fri Feb 27, 2004 9:54 pm

Re: No EVEN Number Altitudes above FL400?

Thu May 16, 2019 7:42 am

RVSM goes up to FL410 with 1000 feet of separation. Above that you need 2000 feet of separation.

The highest two RVSM Flight Levels are thus 400 and 410, but the next two Flight Levels are 430 and 450. 420 and 440 are not permitted.

Image


Nitpick: Flight levels are not altitudes. They are based on the standard atmosphere, whilst altitudes are based on QNH.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
wardialer
Topic Author
Posts: 1205
Joined: Fri Sep 14, 2001 1:08 pm

Re: No EVEN Number Altitudes above FL400?

Thu May 16, 2019 7:54 am

Did not know this, thanks a lot for the detailed explanation.
 
GalaxyFlyer
Posts: 3517
Joined: Fri Jan 01, 2016 4:44 am

Re: No EVEN Number Altitudes above FL400?

Thu May 16, 2019 1:49 pm

For another idea, look at Chilean and Israeli flight levels. You might see planes at FL440; but they’ve been assigned a block level-F430BF450; often when we can’t make the next hard level, ATC can assign a block

GF
 
wardialer
Topic Author
Posts: 1205
Joined: Fri Sep 14, 2001 1:08 pm

Re: No EVEN Number Altitudes above FL400?

Thu May 16, 2019 7:19 pm

Whats the correct Block Level formats for altitudes below FL180?
For example, if an aircraft wanted to request a block level between 5000 to 8000 feet, would this be the correct format below?
050B080

And what if block level requested for altitudes from FL180 to FL220, would this be the correct format?
FL180B220

In your last post, you excluded the "L" and just noted only the "F" (F430BF450)
 
GalaxyFlyer
Posts: 3517
Joined: Fri Jan 01, 2016 4:44 am

Re: No EVEN Number Altitudes above FL400?

Thu May 16, 2019 10:35 pm

“F” is how flight levels are entered in a flight plan and how it shows in the AFTN message and at controller’s position. Below transition level, it would be, I think, A050B080. “A” is used to designate altitudes referenced to local QNH.

B) Cruising Level (maximum 5 characters)

Insert the planned cruising level for the first or the whole portion of the route to be flown, in terms of:

a) flight level, expressed as “F” followed by 3 figures or
Example: F085 (which means flight level 085),

b) standard metric level in tens of metres, expressed as “S” followed by 4 figures
Example: S0150 (which means 1500 meters

c) altitude in hundreds of feet, expressed as “A” followed by 3 figures
Example: A055 (which means 5500 feet altitude)

d) altitude in tens of metres expressed as “M” followed by 4 figures
Example: M0610 (which means 6100 metres altitude)

e) only for uncontrolled VFR flights, the letters “VFR”.


GF
 
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Starlionblue
Posts: 19343
Joined: Fri Feb 27, 2004 9:54 pm

Re: No EVEN Number Altitudes above FL400?

Fri May 17, 2019 3:09 am

In the UK that would be F050BF080 though. ;)

(Most places don't have an 18000 foot transition altitude.)
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo

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