STARS - "FLxxx by XXXX"

[David Gant]

STAR charts might have a note for a flight level BY a certain waypoint. Is that FL an ABSOLUTE value or a MAXIMUM flight level?

 

Example:

My planned enroute Manchester to Gatwick is FL110.

WILLO 3B STAR says "FL150 by KIDLI"

 

I'd interpret that as "If you are higher than FL150, descend to it by KIDLI" but I can't find any guidance.

 

Thanks

Dave

[Andreas Fuchs]

That's [Mod - Happy Thoughts]uming that you are cruising at a regular level of airliners and that is usually well above FL150. Should you be flying lower, just stay there, you certainly won't have to climb to that level.

And if you are cruising low there may be further implications: you possible will have to choose another route + STAR to be compliant. Have a look through all the STAR charts from that direction and read all the notes.

[David Gant]

Thanks for your reply. There are only 3 permitted routes all of which allow FL90-230 and all require that one particular STAR so I think I'm ok.

[Andreas Fuchs]

Good, then go for it!

[Simon Kelsey]

Something worth noting which is broadly specific to the UK is that the altitudes on UK STAR charts are essentially 'suggestions' -- there is a note on the chart with words to the effect "altitudes are given for descent planning purposes only -- actual descent clearance will be as directed by ATC".

 

Thus -- if you are under ATC they are a good guide to what you should be prepared to expect in most situations, but the actual clearance may differ and if this is the case you must follow the instructions given by ATC and not the altitudes shown on the chart.

 

If you are not in receipt of an ATC service then the altitudes on the charts are a good guide to follow .

[David Gant]

Something worth noting which is broadly specific to the UK is that the altitudes on UK STAR charts are essentially 'suggestions' -- there is a note on the chart with words to the effect "altitudes are given for descent planning purposes only -- actual descent clearance will be as directed by ATC".

 

Thus -- if you are under ATC they are a good guide to what you should be prepared to expect in most situations, but the actual clearance may differ and if this is the case you must follow the instructions given by ATC and not the altitudes shown on the chart.

 

If you are not in receipt of an ATC service then the altitudes on the charts are a good guide to follow .

 

Ah yes, I see what you mean. Thanks!

[Andreas Fuchs]

But this is valid almost anywhere in the civilized world. When you are only cleared for a STAR, just follow the horizontal part of it.

[Simon Kelsey]

But this is valid almost anywhere in the civilized world. When you are only cleared for a STAR, just follow the horizontal part of it.

 

This is true -- I suppose the difference is that in the UK you will never get a 'descend via' clearance -- you will only ever get stepped down explicitly by ATC.

[Andreas Fuchs]

Correct, in the UK you will only get SIDs with their infamous "stepped climb profiles". Always good for heartstopping moments when us pilots select the final altitude of the SID and then use VNAV that will level off correctly in between

[Steve Galasso]

If it is a descend via then an a line underneath the altitude means cross it at or above. A line above the altitude means at or below. A line above and below means cross at that altitude.

 

200

—— At or above

 

—— At or below

200

 

——

200

130

—— Cross between 13-20

 

——

150

—— Cross at 150

[Robert Grant]

But this is valid almost anywhere in the civilized world. When you are only cleared for a STAR, just follow the horizontal part of it.

Sorry colleague but I have to disagree. If altitude constraints are marked on SIDs and STARs they are to be complied with unless the SID or STAR restriction is cancelled by ATC and from my experience that applies in most parts of the world..

[Andreas Fuchs]

Hi Rob,

 

of course you have to comply with those vertical constraints, but only if cleared so. If ATC clears you for a STAR, then you follow the horizontal part of it and the speed constraints. Only if you receive instructions to "descend via ABCDE arrival" are you allowed to change level on your own initiative. There are very few places where this is done at all, at most airports ATC will clear you for specific levels/alts and only then may you descend and only then can you respect those altitiude restrictions.

[Alex Ying]

"Descend via" is used in many (most?) parts of the US with FAA procedures, however, it's only used when there are published altitude restrictions and ATC still has to [Mod - Happy Thoughts]ign with the "descend via" phraseology. On procedures with published restrictions but no "descend via" clearance or on charts that only have "expect" altitudes published, the clearance only applies to the lateral portion of the STAR. One of the more frustrating things is when pilots don't comply with these rules and descend when they don't actually have clearance to do so because they misread or don't understand the charts / rules.