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Question: Speed control on final approach

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Question: Speed control on final approach

Old 1st Jul 2022, 05:50
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Question: Speed control on final approach

Edited to be more specific, the following is with respect to the jet aircraft we see most commonly, A320, B738, F100, B789 and A332's.

If a speed of "180kts until 8nm and/or 160kts until 4nm" is issued on final approach, does this impact the workload in the cockpit excessively or are those speeds reasonable and easy to manage?

Are there any workload implications if issued Minimum Approach Speed?

From a pilots perspective, what is your preference on final approach (within about 10nm)?

For the purpose of discussion, lets assume CAVOK with light winds and these speeds aren't drastically different to what you're currently flying.

Thanks

Last edited by Cattill; 1st Jul 2022 at 07:54.
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Old 1st Jul 2022, 07:39
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It depends, very strongly, on Type. DC9, for example, can handle quite high speeds in the circuit and on final. B737 needs a bit more room or delicate speed control. On the turboprop side, for example, prop restrictions on the Dart make it a bit awkward for the F27 but, for the Electra, bring it on. Your question only makes sense if matched with a Type.
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Old 1st Jul 2022, 07:52
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Fair comment John, thanks.

Initial question edited to be more (slightly) specific
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Old 1st Jul 2022, 08:12
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It also depends on the operator's stabilised approach policy. For many years the airline where I flew had a policy that required the aircraft to be stabilised at the final approach speed by 1,000ft AAL, in all conditions. That's since changed to 500ft AAL if required for speed control compliance, but under the old policy, 160kts until 4nm was "problematic", because the aircraft would still be decelerating towards the final approach speed at 1,000ft AAL. If the stabilised approach criteria aren't met, it's a mandatory go-around for many (if not most) airlines.

Minimum approach speed doesn't really have any workload implications unless it's imposed at the last minute, resulting in a flurry of configuration changes to slow down.

Last edited by BuzzBox; 1st Jul 2022 at 12:26.
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Old 1st Jul 2022, 08:26
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Coming back to final approach speed early isn’t really a workload issue. Keeping the speed on longer can be a real problem in something like an A330, which is pretty slippery and not great at slowing down (particularly with any tailwind). 160 to 4nm is bordering on incompatible with stable approach criteria in a 330.
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Old 1st Jul 2022, 09:56
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Smile I’m with you ‘Not-that-hard’

When asked by ATC for high speed to a distance incompatible with my company’s ‘stable approach’ criteria, I simply say we’ll do our best.😉
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Old 1st Jul 2022, 10:00
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Melbourne is a great example. Min speed to achieve a time at the feeder fix, only to be asked to fly max speed to the field
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Old 1st Jul 2022, 10:01
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Originally Posted by itsnotthatbloodyhard View Post
Coming back to final approach speed early isn’t really a workload issue. Keeping the speed on longer can be a real problem in something like an A330, which is pretty slippery and not great at slowing down (particularly with any tailwind). 160 to 4nm is bordering on incompatible with stable approach criteria in a 330.
Agree. Also for the 789. 160 to 4nm is doable as long as conditions are benign.
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Old 1st Jul 2022, 10:03
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Flap limit speeds on some aircraft types make this difficult to comply with, as the limit speed for the landing flap setting is often below 160 KIAS. If you have to maintain 160 until 4 nm (1,200'AGL), then take final flap and complete the checklist (a common requirement for meeting stabilised approach criteria) by 1,000 feet, plus reduce to final approach speed, that simply cannot happen in the 15 seconds/200 feet/.7nm before you reach 1,000 feet AGL. As BuzzBox explained that is a flurry of activity, and the consequence of not being stable at 1,000 AGL (as required by some operators) is a go-around. All the smarttest sequencing in the world comes to nought when a go-around occurs.
I'm told (but can't confirm) that several large carriers simply refuse to accept these "keep the speed up"approaches.
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Old 1st Jul 2022, 10:38
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As others have posted, the A330 is a bit of a pain to slow down and speed brake has its own issues, so I find it more annoying to comply with these restrictions in that type than a 737 for example.

Also it depends on your aircraft weight on the day. Your ideal approach speed could vary by 20kts or more so a restriction that is achievable one day may not be the next.
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Old 1st Jul 2022, 12:41
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Piece of piss in a 320.
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Old 1st Jul 2022, 13:30
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I have not had issues with 160 knots to 4 NM’s in the A330. Workload is almost nothing. Set 160 in the speed window and select managed speed at 4 DME. The 330 slows down and comes down just fine when dirty. I don’t really get the reputation.
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Old 1st Jul 2022, 14:03
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Originally Posted by Beer Baron View Post
Also it depends on your aircraft weight on the day. Your ideal approach speed could vary by 20kts or more so a restriction that is achievable one day may not be the next.
I detail that many people (namely ATC) don't think of, or not aware of, but that makes a difference in this game of pushing airport operations to the limit of capacity.

That 330 is carrying 150 pax, or is it carrying 260 pax ???

Had an occasion of being in approach in a turboprop in between 2 A330s, and at one point I was told by ATC that I was 4.2 nm behind the 330 in front. Way to close for confort, and was asked by ATC what I wanted to do ...
Was able to increase separation a bit and continued approach, landed, and was able to vacate promptly at the first possible exit which is some 600 or 700 meters after touchdown (I knew that the other 330 was behind me). As I was about to be almost completely out of the runway, ATC ordered to second 330 to go around.

Needless to say, the first 330 was a bit light on that day, and its approach speed was on the low side.
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Old 1st Jul 2022, 14:12
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Set 160 in the speed window and select managed speed at 4 DME.
”Speed window” is Boeing terminology. Sure the word window is mentioned in DSC but not in PRO.
Setting speed on an A330 FCU does nothing until selected.
Managed speed is not “selected”. Selected speed is selected.
Speed control can be problematic with regard to stable approach criteria.
As said above, I’ll try.
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Old 1st Jul 2022, 14:20
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As others has said, workload is type dependant, but if ATC need it, you’ve generally left the run too late.

Company I’m at normally has 160kts until 2000’/6nm, holding it until 4nm instead makes all of 6 seconds difference. (As a rough rule of thumb an extra 10kts will be 10 seconds faster for every 6nm at these sort of speeds).

Now a conquest at a previous operator will happily do 245 until 3nm
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Old 1st Jul 2022, 14:40
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Originally Posted by Brakerider View Post
Melbourne is a great example. Min speed to achieve a time at the feeder fix, only to be asked to fly max speed to the field
Why do you think the sequence is absolutely set in concrete? It's a dynamic environment - pilots and controllers screw the pooch, medical traffic into Essendon is slower than expected or downgrades priority, someone requires a speed reduction, conditions change allowing reduced spacing, number 1 in the sequence is able to accept track shortening opening the sequence up,........
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Old 1st Jul 2022, 16:46
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B738

I’m very comfortable at 210-200 to 12 miles reducing to 180 to 5 is doable, 160 to 170 to 4 is not a great problem.

does it impact on workload - yes, but only if you haven’t prepped it, if you’ve briefed it effectively it’s not a big drama.
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Old 2nd Jul 2022, 13:17
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I seem to remember (while ago now) the Westwind would give us 350 to 4 mile final, allowing us to slot a lightie into the sequence via a right or left base before the next jet arrival. The 727 was also good at keeping the speed going to a shortish final. Just like in ATC (with separation assurance), pilot standard operating procedures have been dumbed down to cater for the lowest common denominator.
If you can't do 160 to 4, just say I can do 160 to 5 or 6 - it will make bugger all difference to the sequence.
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Old 2nd Jul 2022, 15:19
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I have about 6000 hours each on 737 and A320, about 4000 on BAe 146 and 1500 on Westwinds.

180 to 6nm and 160 to 4nm isn't a problem on any of them, unless very light (because you have a very low final approach speed, so you need to slow down more to make stability criteria) or a tailwind. (and in the same way, 190 at 7nm, 200 at 8nm, 210 at 9nm and 220 at 10nm all easily doable - just throw out the gear for that 10 knot per mile decelation on a 3º slope.)

I seem to remember (while ago now) the Westwind would give us 350 to 4 mile final,
Well ... FOUR miles is a bit tight !!
MMO into VMO for descent - which is M.765 into 360 knots, and hold that 360 knots to a 90º intercept on the ILS at 10nm was doable.
(Set up the VOR on the runway track - to give you 10º of lead when the needle moves - as soon as the needle moves, Bank 30º, thrust idle, speed brake out - which gives a good pitch up for the turn in a Westwind - then flap one at 240, flap two at 220, gear at 180 and flap full to cross the fence still at idle and slowing past Vref.)
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Old 2nd Jul 2022, 15:47
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Originally Posted by Checkboard View Post
I



Well ... FOUR miles is a bit tight !!
MMO into VMO for descent - which is M.765 into 360 knots, and hold that 360 knots to a 90º intercept on the ILS at 10nm was doable.
(Set up the VOR on the runway track - to give you 10º of lead when the needle moves - as soon as the needle moves, Bank 30º, thrust idle, speed brake out - which gives a good pitch up for the turn in a Westwind - then flap one at 240, flap two at 220, gear at 180 and flap full to cross the fence still at idle and slowing past Vref.)
Full flap and gear down with the power levers at flight idle close to the ground, what could possibly go wrong
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