STAR/Approach Question

Flying into Dubai on an A380, it was much more crowded than I expected. I had expected to enter via the VUTEB STAR. When I entered Dubai Center, the center told me to descend to 4,000 feet; I was still at 12,000 feet because I was approaching my STAR. I tried to descend to 4,000 feet, but couldn’t go faster than 100 feet per minute because I had to reduce my speed to 260 knots. I managed to get under 260 knots, so then I went for a more aggressive descent of 500 feet per minute. Then at about 8,500 feet, the controller told me again to descend to 4,000 feet and to maintain 190 knots. I realized that it was impossible for me to continue this landing, because I was still at 250 knots and couldn’t descend quickly enough without exceeding 260 knots, so I decided that executing a holding pattern to lose altitude and speed was the only solution. Therefore, I replied “unable” to his request to slow down and descend, and then announced a missed approach; about 5 seconds later, I received a Level 3 violation.

What should I have done in this situation? I realize I was descending too fast overall, but how should I have communicated better to the controller that I needed a holding pattern?

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Hello @Aslan_S!

I believe that your descent rate of 100 fpm is very low. Your aircraft can easily go over 1000 fpm on descent, and that is what ATC expected you to do. To reduce your speed, using your “flight” spoilers, and flaps (if your speed allows it) can help you slow down to that speed. If you want to appeal your violation, i’d do so by either PM’ing that active controller, or by messaging the @appeals team.

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Yes, 100 fpm is really low, but I had flaps fully extended and if I went over 700fpm speed would start increasing again.

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Have you PM’d the controller that gave you that violation? That way they will be able to help you out the most in this case.

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I just did. Thanks

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Flaps on the A380 don’t add to the drag. The wing is huge relative to the fuselage and weight thus causing it to accelerate due to the excess lift available.

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Flaps fully extended at 12,000 feet? Odd. For me, I can descend at like 1500 without speed changing, and using flight spoilers when necessary…

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To be honnest, it happens quite often than ATC forget to check the altitude aircrafts are flying at when giving instructions. I was not happy yesterday to be given a “check the user guide…” message after being forced to choose between diving @3000ft/min. + overspeed with an A380, or saying “unable”. Sometimes, it would be better, when possible, to take a few seconds to see what the reason behind the “Unable” message might be.
My two cents.

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Unable is to be used when ATC vectors you towards a mountain.

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Using spoilers flight when descending to 10000ft. It helps you well.

So what should I have done? Sorry but unable means just: I am sorry but I cannot act as instructed.

There’s always a solution.

What you can do is keep a steady level, slow down to ≈220kts and then dive 3000+ft/min to avoid overspeeding.

This is possible IRL (I’ve seen -4900ft/min last week in a 737 descending through 13.000ft)

Also if you’re above 10.000ft and want to slow down to 250kts you must be proactive and anticipate your descending speed at all times.


« cannot act as instructed » only occurrence I can think of regarding the impossibility to act is going straight towards a mountain. Where the only input to avoid a crash will violate ATC’s instructions, that’s where you can say unable or divert from vectors.

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Full flaps is only required at slower speeds like 150kts-160kts Airspeed. Here is the best way to handle the flaps during decent.

Flaps 1 at 230kts (flight spoilers to slow down)
Flaps 1 + F at 200kts (flight spoiler to slow down)
Flaps 2 at 185kts (armed spoilers)

By this point you don’t need flight spoilers to slow down also 185kts is the slowest you can maintain altitudes at. As you begin the next decent slow down to 170kts airspeed.

While you prepare for final approach stage here is the final flap configuration.

Flaps 3 at 160kts
Flaps full at 150kts

Make sure when you are decending next time to use the flight spoilers to slow down and not the flaps. Improper flap configuration is what prevented you from proper decent and follow ATC instructions. I hope this helps

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I think if you used your spoilers to get you to slow down, you would have gotten the assigned Alt and the speed. Me personally i would went 1600 to 2000 feet a minute with spoilers helping me. If i was IFATC i would have sent you on a hold to lower you down to a suitable altitude, (you can get rid of the speed quite fast). traffic permitting and then reassign you a new approach. Don’t take it to heart. All the best pilots have violations, i have a few also but you learn from them.
All the best
Alan

What might work next time is descend to about 10500 or 11K while lower your speed to 250 kts. If you were still above 260, stop your descent at about 10,500. From there you should slow down rapidly in about 15-30 seconds and at that point you should be able to descend at a descent levels to avoid any atc or overspread violations .

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This is untrue. There are other moments when unable can be used by the aircrew. Being unable to meet performance requirements/crossing restrictions is one of those.

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Hello, I’m one of the radar controllers in IFATC, please allow me to share my two cents.

At this point, you should have started slowing down to under 260kts, in normal situation 250kts is the max speed you should fly under 10000ft. ATC should be awared of how hard it is to slow down the plane while descending.

500ft per minute is quite slow while your speed is in control, have you tried to extend the speed brakes to descend more rapidly?

According to my research, the VFE - maximum flap extend speed of the A380 is 260kts at flaps 1, I saw some Youtube videos of real life pilots records their flight, sometimes they extend the flaps even if they don’t need the lift in order to slow down the aircraft, this should be a good way to slow down too. More flaps extended = more drag.

I think the controller might be confused by your slow descend, and in order to vector you to the airport in a appropiate altitude or for spacing issues, he/she instructed you to slow down.

As a radar controller, I don’t recommend to diviate from your flight plan wthout ATC’s vector, this will only add more misunderstanding.

And this is why the controller chose to give you a violation. I can totally understand their feelings.

Sometimes there’s nothing you can do by using the limited communication method in this situation, maybe, you can contact the controller and discuss the issue with them to have a better perspective from the ATC’s side, and plan for a better descend when flying into a ATC staffed airport next time.

Hope you will still be confident and enthusiastic when flying again in Expret Server!

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