ATC assign descent below altitude constraint while on a RNAV STAR

Avstar · 18th Nov 2011, 13:43

Hello,

Just a quick question for you ATC guys?

If ATC clear an aircraft which is on a published RNAV STAR, to descend below an actual altitude constraint on the STAR. Can the aircraft descend to the ATC cleared altitude, ignoring the STAR constraint. Or should the aircraft respect the constraint and then further descent to the ATC assigned altitude. (The aircraft in question was cleared for the RNAV STAR.)
Thanks

chevvron · 18th Nov 2011, 15:51

If adequate terrain clearance is still provided and the aircraft does not descend outside controlled airspace; the controller may after all be trying to expedite traffic during low traffic periods.

2 sheds · 18th Nov 2011, 16:57

ICAO PANS-ATM

Quote:

When an arriving aircraft on a STAR is cleared to descend to a level lower than the level or the level(s) specified in a STAR, the aircraft shall follow the published vertical profile of a STAR, unless such restrictions are explicitly cancelled by ATC. Published minimum levels based on terrain clearance shall always be applied.

DESCEND TO (level) [LEVEL RESTRICTION(S) (STAR designator) CANCELLED (or) LEVEL RESTRICTION(S) (STAR designator) AT (point) CANCELLED]

2 s

ron83 · 18th Nov 2011, 16:58

Altitudes constraints shall be observed unless cancelled by atc.

poldek77 · 18th Nov 2011, 18:13

Here you can find some good training material from Eurocontrol.
https://trainingzone.eurocontrol.int.../runcourse.htm
For this specific topic go to "TMA Operation" tab, page 5/12 and "Select Activity 2 to check your understanding."

Neptune262 · 18th Nov 2011, 18:56

This may help:

http://www.caa.co.uk/docs/33/FOD201009.pdf

Shows ICAO and UK difference.

Avstar · 19th Nov 2011, 10:26

Thanks Very Much!!

Appreciate all your expertise. It is as I thought.

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