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160kts til 4dme

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160kts til 4dme

Old 6th Dec 2012, 21:40
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160kts til 4dme

Specifically A320 operators, what drag technique are you using in LHR to reduce from 180kts conf2 to 160kts. Speedbrake, gear, F3??
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Old 7th Dec 2012, 09:56
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Most of the times, if F2 isn't enough, L/G followed by F3. On a normal day it is enough to be stabilized by 1000'.

Last edited by C212-100; 7th Dec 2012 at 14:07.
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Old 7th Dec 2012, 12:48
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For a time, ATC at Stansted allowed us to fly 170 to 5, yet it was scrapped. I would be interested to know why, because the 737-8 F5 speed is around 165kts! We are left with two choice - dirty up for the sake of 5 knots, or just fly 165 and hope so the best. Some guys at STn even recognise this and give us 165 to 4.
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Old 7th Dec 2012, 13:47
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Depends to a large degree on variables such as weight, winds etc, but generally I would be flap 1 at 180, and then select flap 2 when asked to reduce to 160. If this is not enough then either flap 3 or a bit of speed brake to bring it back to 160....
At somewhere between 4 and 5 miles I'd then go for gear down, managed speed to start reducing to Vapp, again depending on wind, aircraft type, Vapp and landing flap.
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Old 7th Dec 2012, 14:50
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This is a problem in my company as well,
If we are heavy and Vapp is relatively high , there is no problem reducing from 160kt but if we are light and Vapp is relativel low like 125-130kts , there is no way to be stable at 1000ft.

What i do is
180kt ( CONF 2)
at 6 miles Gear Down
Speed Selected 160kt
Flaps 3 and Full
at 4 miles , managed speed .
It bearly comes to a stable approach with the speed , and engines are spooled up.
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Old 9th Dec 2012, 22:39
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Gear Up!

Non-standard Flaps3!
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Old 10th Dec 2012, 01:23
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One of the reasons for keeping 160kts to 4DME is to try to reduce the noise footprint over heavily populated areas (as well as getting most efficient runway usage).

You will give yourself problems if you use the technique as described above....

What i do is
180kt ( CONF 2)
at 6 miles Gear Down
Speed Selected 160kt
Flaps 3 and Full
at 4 miles , managed speed .
It bearly comes to a stable approach with the speed , and engines are spooled up
As you say, it barely comes to a stable approach with the speed.

When you put your gear down in selected speed, power comes up to compensate for the drag, as you then go to flap Full you need even more power. The result of this is that when you go for managed speed at 4 miles it takes longer to slow down due to the power setting when you go managed. Result is noisy approach that struggles to be stable by 1000 ft.

If you are at Flap 2 and 160 kts at 4DME your power will be low, take managed speed,gear down, Flap 3 then immediately Full and you will find that by about 1100 ft you are fully configured, speed is within 5 kts and the engines are spooling up nicely......amend as required for tailwinds!
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Old 10th Dec 2012, 08:07
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non standard flap 3

2 nights ago, it was a heavy A321 with us, LHR so I used flaps three and on 4.5 miles gear down and managed speed, which barely got the speed below 160 by 4 but enough to be stabilized by 1000. but then my Vapp 142
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Old 10th Dec 2012, 08:54
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Bengerman ,
Just to make it clear ,
4 DME = 1200ft
and you say
gear down+ flaps 3 +flaps full + reduce to Vapp + Spool Up
takes just 100 ft and you are stabilized at 1100ft??
There is no way of achiving it.Not in this world at least.

In my opinion this "160kt till 4 "thing is not just about noise, priority is the squencing of the aircrafts.The crowded airports like LHR they keep 2.5 miles between the aircrafts on final and they need precise speeds to use the airport at maximum.
And they are ridicilously strict about this thing that , there was a report i saw , saying we crossed 4 miles at 159 kt.

You are right about the noise( actually its not beyond the limits) but after i saw that report i use my tecnic.
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Old 10th Dec 2012, 09:34
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In my opinion this "160kt till 4" thing is not just about noise, priority is the squencing of the aircrafts. The crowded airports like LHR they keep 2.5 miles between the aircrafts on final and they need precise speeds to use the airport at maximum.
And they are ridicilously strict about this thing that , there was a report i saw, saying we crossed 4 miles at 159 kt
Yes, that's clearly the case at LHR. The difference between, say, 160kt and 150kt is 3 extra landings per hour, which is a huge difference when you're operating at 99% of capacity for much of the day.
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Old 10th Dec 2012, 09:41
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Okivan, that's fine, you carry on doing what you are comfortable with.

The method I describe has been working for me for several years, no complaints from ATC and no real issues with being stable, after making appropriate adjustments for tailwinds, too close to the heavy in front, A319 with low weights etc.
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Old 10th Dec 2012, 11:17
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Out of interest, over what distance is keeping to 160 kts required (i.e. where is the start point, if the end point is at 4 NM)?

Is this standard for busy airports, or is LHR special in this respect? Are most aircraft able to comply with this speed restriction (from turboprops to heavies)? Judging by the responses above, I would say yes...

Regards

NotaLOT
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Old 10th Dec 2012, 11:25
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Nota - Anything from 15-6 miles.

Technique we mostly use. 160 F2 (watching ND to see how quickly to achieve it....If you are already 2.5nm behind when told to reduce - Speed back quick!)

At 4.5d, managed speed. All that happens is the engines wind down to idle. 160kt normally maintained.

At 4d, gear/F3 then flap full quite quickly. As the gear comes down it creates additional drag which helps slow down. Generally achieve Vapp with (some) power at 1000'. Light A319's take a bit more!

Okivan's technique works, but creates additional noise to 4d, also as there is so much power on at 4nm the engines will take a while to wind down again and slow down.
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Old 10th Dec 2012, 11:28
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<<Out of interest, over what distance is keeping to 160 kts required (i.e. where is the start point, if the end point is at 4 NM)?>>

The instruction applies from the moment it is given until you are 4DME on the ILS.
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Old 10th Dec 2012, 11:30
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I really don't get this method... Do ATC expect instant reduction to 160 kts, iaw bring out the drag to reduce to 160 and then apply power to maintain 160? Doesn't seem very efficient from both an environmental (fuel) and noise footprint perspective.

I really believe this system needs a revamp taking into account a speed reduction segment.

My operator requires us to go gear down at 5NM AND managed speed. If I hurry to slow from 180 to 160 I will never do 160 to 4nm.

Last edited by 737Jock; 10th Dec 2012 at 11:31.
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Old 10th Dec 2012, 14:01
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To get from 180kts to 160kts we generally select flap 2, and even flap 3 if it's required. Once flap 3 is out it shouldn't be a problem. Often the reduction is at about 10dme on the ILS so if you're descending to 3000ft then you can stay below the glide (only slightly) using V/S and then when its asked for you can take flap 2 which will "bump" you onto the glideslope and give you the reduction to 160kts. Agreed, if there's a tailwind it's a struggle so will generally end up using speedbrake. In my company (a very heavy LHR user) we generally drop the gear and manage the speed from 160kts at between 4 and 4.3dme, works every time for being stable at 1000 (occassionally the speed may still be slightly high but only by 10/15kts and reducing). Only in a very light 319 could it be an issue, or with a tailwind.
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Old 10th Dec 2012, 16:44
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Flap 2, 160kts (speedbrake if not holding it), 4nm, managed speed, Gear down, Flap 3, Flap full.

Configured by 1000ft which meets our company requirements, speed normally either stable or slightly out, but we have an extra 500ft to reduce once through a 1000ft.

Unless there is a stupid amount of tailwind then it pretty much works every time.

Some people get twitchy sometimes about the speed, but I have never had to go around at 500ft due to excess energy.

I was sceptical at first until I flew with a very good trainer who demonstrated it, since then I have been converted. If the speed is holding stable at 160kts you could push managed speed early and the majority of time aircraft will hold 160kt with the speed target at Vapp.

As ever so many techniques whatever makes you comfortable.
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Old 11th Dec 2012, 09:30
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<<Doesn't seem very efficient from both an environmental (fuel) and noise footprint perspective.>>

Maybe not, but that's not the priority which is to achieve max landing rate as demanded by the airlines taking into account various other factors such as wake vortex separation..

<<I really believe this system needs a revamp taking into account a speed reduction segment.>>

What would you suggest as an alternative?

Last edited by HEATHROW DIRECTOR; 11th Dec 2012 at 09:31.
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Old 11th Dec 2012, 09:36
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For a time, ATC at Stansted allowed us to fly 170 to 5, yet it was scrapped.
Yes it was a trial that was never adopted. The 738 works lovely at 170, but 160 requires the gear down/F15 so not fuel/noise efficient at all. There is nothing to stop you requesting '170 to 5' on first contact with Essex for STN which I'm more than sure they'll accommodate when they can. I do it regularly with LTN (request on first call with LTN Director) as based there, and have always had it accepted

Technique we mostly use. 160 F2 (watching ND to see how quickly to achieve it....If you are already 2.5nm behind when told to reduce - Speed back quick!)
I'd suggest just flying the allocated speed as promptly as possible on all occasions and not second guess compliance promptness based on TCAS seperation with the one ahead. Whilst 2.5nm is the MINIMUM, Wake Vortex seperation from the one ahead may well demand a greater seperation than that. The requirement to report aircraft type on first call is so they can confirm that the wake seperation they apply is legal. The final approach seperation is ATC applied in accordance with the rules, they're bloody good at it and LHR are abosolute masters at it - no second guessing or basing speed reduction on TCAS from us - just do as we are told and the system works extremely safely and efficiently
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