Straight in approach
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Straight in approach
Hi everyone,
I'm after some opinions on an issue that cropped up the other day.
On an arrival to a non- radar airfield on a published arrival. The 25nm msa was 3500ft in all sectors. The arrival had us maintaining 8500ft until approx 20nm from the runway which mean we would've been approx 2-3000ft high on profile.
Short of slowing down and making a dirty dive toward the runway what were our options? (Apart from taking up a hold overhead to lose the height) I'm talking legally here as terrain wasn't a factor so we could have disregarded the 8500ft and made a nice relaxed decent. From a safety point of view we were well above msa so the 8500ft must be an airspace/atc restriction.
As far as I know in a non radar environment we must adhere to the published arrival unless on a visual approach ( we weren't visual)
Do Atc have the authority to clear us below the arrival minimum alts?
We were cleared buy Atc to descend to 3000ft and cleared for the iLs many miles out.
Thanks
I'm after some opinions on an issue that cropped up the other day.
On an arrival to a non- radar airfield on a published arrival. The 25nm msa was 3500ft in all sectors. The arrival had us maintaining 8500ft until approx 20nm from the runway which mean we would've been approx 2-3000ft high on profile.
Short of slowing down and making a dirty dive toward the runway what were our options? (Apart from taking up a hold overhead to lose the height) I'm talking legally here as terrain wasn't a factor so we could have disregarded the 8500ft and made a nice relaxed decent. From a safety point of view we were well above msa so the 8500ft must be an airspace/atc restriction.
As far as I know in a non radar environment we must adhere to the published arrival unless on a visual approach ( we weren't visual)
Do Atc have the authority to clear us below the arrival minimum alts?
We were cleared buy Atc to descend to 3000ft and cleared for the iLs many miles out.
Thanks
We were cleared buy Atc to descend to 3000ft and cleared for the iLs many miles out.
So with clarification from ATC the 8,500 ft restriction could have been cancelled?
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Thanks for the replies
The airport is Rabat (GMME) with the STAR onto iLs runway 21.
Yes we could have disregarded the 8500ft minimum (safely in fact as msa is 3500ft) but I'm after what is technically correct. This wasn't a altitude restriction at a waypoint but a minimum altitude along the track on the STAR.
Thanks
The airport is Rabat (GMME) with the STAR onto iLs runway 21.
Yes we could have disregarded the 8500ft minimum (safely in fact as msa is 3500ft) but I'm after what is technically correct. This wasn't a altitude restriction at a waypoint but a minimum altitude along the track on the STAR.
Thanks
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737aviator:
When posts like the OP's don't include the ICAO identifier I ignore them.
I think we really need to know the airport and the arrival to look at its charts ourselves.
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If you were on no radar then you have two choices:
If your operator allows and if you are in VMC you may request a visual approach or in that case follow the procedure arrival which may require you to join the holding to establish into the specified reversal procedure.
In that case i guess,the 3000 feet was the altitude shown as a minimum over the holding and ATC is expecting you to follow all IFR level restrictions on that arrival.(ATC would say some like:cleared xyz arrival,descend 3000 ft,call outbound..).
Be on the safe side.
If your operator allows and if you are in VMC you may request a visual approach or in that case follow the procedure arrival which may require you to join the holding to establish into the specified reversal procedure.
In that case i guess,the 3000 feet was the altitude shown as a minimum over the holding and ATC is expecting you to follow all IFR level restrictions on that arrival.(ATC would say some like:cleared xyz arrival,descend 3000 ft,call outbound..).
Be on the safe side.
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As above a reference would help but does this arrival lead straight in itself or initially to a hold?
My thinking is that if you ask ATC to clear you to some point that isn't on the arrival itself or clear you directly on to a part of the approach you could say that you are no longer flying the arrival and therefore the arrival restrictions won't apply.
We commonly do this at airports with an arrival to a hold overhead the field then an outbound track and base turn for the ILS, we often request to route directly to a x nm final on the ILS and normally (after sometimes checking our "distance dme") we are told "approved, descend in accordance with minimums"
My thinking is that if you ask ATC to clear you to some point that isn't on the arrival itself or clear you directly on to a part of the approach you could say that you are no longer flying the arrival and therefore the arrival restrictions won't apply.
We commonly do this at airports with an arrival to a hold overhead the field then an outbound track and base turn for the ILS, we often request to route directly to a x nm final on the ILS and normally (after sometimes checking our "distance dme") we are told "approved, descend in accordance with minimums"
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Thanks for the replies.
As I've just signed up my posts seem to take a while to appear as i think they need to be checked or something.
Feel free to continue to ignore it. No one can make you answer. I am very grateful to the people who have.
Well this is what we did. And it caused great confusion from atc as evidently every other operator just descend straight to 3000ft as per atc clearance disregarding the 8500ft lowest alt on the STAR. (Which is safe as it is above msa...) They cleared us for 'straight in ILS 21'
It also caused anger/confusion from the traffic behind us who were asking why we were 'holding'. It also seemed like a stupid thing to do but technically correct I think.
As I've just signed up my posts seem to take a while to appear as i think they need to be checked or something.
aterpster
Quote:
I think we really need to know the airport and the arrival to look at its charts ourselves.
When posts like the OP's don't include the ICAO identifier I ignore them.
Quote:
I think we really need to know the airport and the arrival to look at its charts ourselves.
When posts like the OP's don't include the ICAO identifier I ignore them.
follow the procedure arrival which may require you to join the holding to establish into the specified reversal procedure.
In that case i guess,the 3000 feet was the altitude shown as a minimum over the holding and ATC is expecting you to follow all IFR level restrictions on that arrival.(ATC would say some like:cleared xyz arrival,descend 3000 ft,call outbound..).
In that case i guess,the 3000 feet was the altitude shown as a minimum over the holding and ATC is expecting you to follow all IFR level restrictions on that arrival.(ATC would say some like:cleared xyz arrival,descend 3000 ft,call outbound..).
It also caused anger/confusion from the traffic behind us who were asking why we were 'holding'. It also seemed like a stupid thing to do but technically correct I think.
Cross the RBT D21 fix at FL85, descend on your clearance to 2700' at SBI, which is 12.5 track miles to lose the height. The required gradient is 464'/nm and, if slowed at the D21 fix, should be easily doable. At 180 KIAS, the descent rate is about 1400 fpm.
GF
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Galaxy Flyer, exactly what I'd do if I saw this plate. Everyone kept happy, everyone safe and no holding. On a 737 anyway, you probably won't even need speed brake, but perhaps Flaps 10 would be useful. 
I go into many radar controlled airports that keep us similarly high for various reasons and don't see this arrival as particularly unusual; if fact you know what to expect so you've plenty of time to plan and discuss the descent. Just like GRO (LEGE).
Other options; ask ATC if the STAR descent restrictions are cancelled; e.g. 'confirm unrestricted descent?'. The FL85 could simply be there due to traffic from somewhere else below.
Otherwise, if in doubt, then doing a lap of the hold is of course the best thing to do as you're sure its protected. It's ATCs problem to worry about the traffic behind, not yours.
I go into many radar controlled airports that keep us similarly high for various reasons and don't see this arrival as particularly unusual; if fact you know what to expect so you've plenty of time to plan and discuss the descent. Just like GRO (LEGE).
Other options; ask ATC if the STAR descent restrictions are cancelled; e.g. 'confirm unrestricted descent?'. The FL85 could simply be there due to traffic from somewhere else below.
Otherwise, if in doubt, then doing a lap of the hold is of course the best thing to do as you're sure its protected. It's ATCs problem to worry about the traffic behind, not yours.
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Thanks again for the replies.
Perhaps we were being over cautious. Although the RBT dme reads 1nm at the threshold so we have to remain at fl85 until 20nm from the runway. On the day with a high QNH that meant we were 9000ft at 20nm with a 15-20kt tail wind (becoming 'calm' on the ground) as well as the temp being in the high 30s. We probably could have made it straight in but it would have been a bit busy.
Perhaps we were being over cautious. Although the RBT dme reads 1nm at the threshold so we have to remain at fl85 until 20nm from the runway. On the day with a high QNH that meant we were 9000ft at 20nm with a 15-20kt tail wind (becoming 'calm' on the ground) as well as the temp being in the high 30s. We probably could have made it straight in but it would have been a bit busy.
With those winds and conditions you might need closer to 2000fpm at 180 KIAS; steep but controllable. Or ask if the F85 restriction couldbe removed.
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Were you cleared to "descend via" the arrival, or just cleared to descend to 3000'?
If you are cleared to 3000' (AND cleared for the approach), why would you level at 8500'?!?
Where you fly, does an ATC altitude clearance not pre-empt a published altitude limit?!?
If you are cleared to 3000' (AND cleared for the approach), why would you level at 8500'?!?
Where you fly, does an ATC altitude clearance not pre-empt a published altitude limit?!?
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Intruder, there's often a bit of confusion around Europe/North Africa with altitudes and cleared levels as controllers in different countries may not be clear with their level of English and how they express their instructions.
I'm more familiar with this in the climb on departures, where on a SID one could be cleared to FL120, but have intermediate crossing restrictions such as FL80B, FL100B, etc. The controllers at these airports will usually say something like 'Climb FL200 Unrestricted', and if they don't I'd always ask them to confirm that the climb is unrestricted, as the climb to FL200 is still subject to the SID restrictions unless they cancel them. UK controllers will clarify this by saying 'Climb NOW FL200'. The full phraseology that should be used is actually quite long and wasteful of RT time which is probably why the UK has this difference.
It's also very clear in ICAO guidance, that aircraft on a STAR should follow all the vertical restrictions published in the STAR unless those restrictions are cancelled by ATC in the descent clearance. So if the a/c has previously been cleared on an arrival here then a "Intruder737, Descend altitude 3000ft" clearance does not allow the pilot to go below any published 'At, At or Above' restriction. However if the controller hasn't given descent and you're not going to be able to make a 'At or Below' restriction then let him worry about it.
Edit; just found this which explains it nicely: https://www.caa.co.uk/docs/33/FOD201009.pdf
I'm more familiar with this in the climb on departures, where on a SID one could be cleared to FL120, but have intermediate crossing restrictions such as FL80B, FL100B, etc. The controllers at these airports will usually say something like 'Climb FL200 Unrestricted', and if they don't I'd always ask them to confirm that the climb is unrestricted, as the climb to FL200 is still subject to the SID restrictions unless they cancel them. UK controllers will clarify this by saying 'Climb NOW FL200'. The full phraseology that should be used is actually quite long and wasteful of RT time which is probably why the UK has this difference.
It's also very clear in ICAO guidance, that aircraft on a STAR should follow all the vertical restrictions published in the STAR unless those restrictions are cancelled by ATC in the descent clearance. So if the a/c has previously been cleared on an arrival here then a "Intruder737, Descend altitude 3000ft" clearance does not allow the pilot to go below any published 'At, At or Above' restriction. However if the controller hasn't given descent and you're not going to be able to make a 'At or Below' restriction then let him worry about it.
Edit; just found this which explains it nicely: https://www.caa.co.uk/docs/33/FOD201009.pdf
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I also found this in FAA INFO 12003:
So, there's even a difference between the US and Canada. The solution is easy, though it does take a few seconds on the radio: "Approach, confirm altitude restrictions cancelled?"
The Federal Aviation Administration (FAA) has implemented STAR procedures utilizing “DESCEND VIA (STAR designator)” phraseology to indicate to flightcrews that compliance with the lateral track and vertical profile of the STAR is required. In this case, if ATC assigns an altitude to a flightcrew following a STAR, whether or not “DESCEND VIA” has been issued; any published altitude restrictions are cancelled unless reissued by ATC. This is opposite to the Canada/ International Civil Aviation Organization (ICAO) procedure in which published SID/STAR altitude restrictions remain mandatory unless specifically cancelled by ATC.
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I think it's pretty clear, in a non-radar environment, if ATC clear you for the procedure then follow the published procedure altitudes and follow the STAR altitudes and then transition from the STAR to the approach procedure, which would probably be to descend via a hold before accomplishing a procedure turn etc....
If cleared straight in approach and descend to 3000' by ATC then descend to 3000 or MSA until established on the glide end of...
If cleared straight in approach and descend to 3000' by ATC then descend to 3000 or MSA until established on the glide end of...
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To reinforce what has already been stated ICAO Doc 44444 requires altitude restrictions on SIDs and STARs to be specifically cancelled (refer Doc 4444 6.5.2.4 Descent below levels specified in a STAR and 6.3.2.4 Climb clearance above levels specified in a SID)
The phraseology used to achieve the above varies around the world. ICAO have been addressing this issue and I believe should be advising updated recommended phraseologies by Nov 2016. The specific cancellation of individual elements of a SID/STAR most likely will remain.
Altitude requirements are stated on SIDs and STARs for:
Obstacle clearance \ Airspace containment \ ATC separation. ATC can only cancel ATC elements (unless radar terrain is applied for obstacle clearance). It is often not clear on SIDs/STARs exactly which restrictions are ATC ones so beware if what appears to be an unrestricted descent is received e.g. its the pilots responsibility to remain within controlled airspace. Ideally Annex 4 re charting standards need updating as well.
All the above is critical in the PBN environment.
The phraseology used to achieve the above varies around the world. ICAO have been addressing this issue and I believe should be advising updated recommended phraseologies by Nov 2016. The specific cancellation of individual elements of a SID/STAR most likely will remain.
Altitude requirements are stated on SIDs and STARs for:
Obstacle clearance \ Airspace containment \ ATC separation. ATC can only cancel ATC elements (unless radar terrain is applied for obstacle clearance). It is often not clear on SIDs/STARs exactly which restrictions are ATC ones so beware if what appears to be an unrestricted descent is received e.g. its the pilots responsibility to remain within controlled airspace. Ideally Annex 4 re charting standards need updating as well.
All the above is critical in the PBN environment.