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Airbus Energy Management.
As we are all probably familiar with the ATC requirement to maintain “160 to 4NM” could I ask the question as to how you manage this request in terms of aircraft configuration. Option 1 being fully configured with gear down and flaps full extended and manage the speed at around 4.5 NM or option 2 which is remain gear up flap 2 and then manage speed at 5 NM and then gear down and the remaining flap. I would be interested as an instructor to hear your opinions and as I do not have access to the sim for a few days and would not be able to experiment with the two techniques. |
The latter, as it's low drag and low noise. Works well on the 737 with its respective flaps setting and speeds.
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Option 1, and depending on the wind, start reducing at 5nm if you want to guarantee stability at 1000ft. |
Option 2 is too close to the 1000’ point and too tight in my opinion; with gear and two/one stages of flap and landing checks still to do. It is good practice to make one config change at a time and let the aircraft settle after each one. PM will probably be doing radio calls at that point as well, so if you leave it until 5 miles before gear and final flaps, PF might have to speak over PM and ATC to ask for config. It’s not impossible but it could get messy ! |
Well, it was pretty much the norm to keep 160 selected and F2 until 5NM, at that point push managed speed and configure with gear and flaps. I agree it was quite tight, but not so much. With some tailwind/heavy wight could definitely become tight. Maybe with that technique we ended up being significantly less than 160 at 4NM, especially with light weights. Now I see it’s far more common keep 160 and while maintaining 160 going gear down at around 6/5.5NM and continue configuring with F3. Then slightly before 4NM select managed speed and flap full if desired. In this way at 4NM we are 160 or at least very close. |
The company's interpretation of the 1000' gate forces your hand. And there are quite a few. Then, once you come to decide which is your preferred option, the wind of the day might necessitate using the other one.
My baseline is F2 160kt to 4,4 then L/G DN, (pause 2 sec) manage SPD. The idea is to have at 4,0: idle thrust, gear down, wheel door closing. When L/G cycle is completed, F3, F4: the trick lies in achieving setting of F4 soon enough, before the A/THR comes to protect the F-speed while F3 are out. In a real IMC, LG DN at 4,5 and manage SPD at the same time keep a bit of margin to avoid raised eyebrows, but 155 or even 150 by 4,0 is what you get. Especially wise guidance in Uplinker's second paragraph. PM's liaison with ATC will spoil the show somewhat. Short version: the deccelarated LP/LD Gear UP approach method on the SA Airbus is not really compatible with ATC fixed speed 160 to 4.0D |
Thank you for your inputs. With regards to the A330 specifically, the theory is to remain clean as then power will be low as the drag will be less and once managed speed is selected and then gear down the gear would act as a brake. I personally have been selecting option one and if the speed refuses to trend towards Vapp I extend the speed brake and then take final flap. The A330 is particularly unique in that it is still a CAT C aircraft and has very low approach speeds compared to the A320. |
IMC or VMC?
IMC, configuring near 1000' would result in the crew still completing checks close to or below 1000', and possibly missing ALT crosschecks for CAT I approaches. For VMC, depends on the airlines operational procedures, and what constitutes a stable approach. For an Airbus, the ATR works nicely managed so flaps for the speed is a nice option, that means having gear out. As far as drag goes, as you get below 2000' some drag is going to be necessary to manage speed, and gear does that nicely. For a Boeing, the AT system is handraulic so having flaps out and dropping the gear works fine and doesn't risk the Airbus ATR overriding to reduce speed and disconnecting the ATR close to the ground. In all cases, the time from your target speed reduction point to passing 1000' is about 35-45 seconds, and the speed reduction is about 20-30 kts, about 1kt/sec which is not excessive, but also needs to be monitored. KISS would increase operational safety and minimise visits to the QAR process managers office. |
At LGW, at least with my company, the usual is F2 160 kts. Then at c.5 miles depending on wind, drop the gear. Then at c.4.3 manage speed, F3,FF, landing checklist. Unless it’s a light wind / tailwind you’re always stable at 1000. I do often hear BA asking for 160 to 5nm instead which atc always accept. |
Don’t want to drift OT, unfortunately as FlightDetent said the standard decelerated approach is something I really managed to fly rarely. I like to select F1 around 3NM before FDP, then F2 latest 2000’ and continue configuring all the way down. Unfortunately either because some procedures ask fixed speeds at certain points (fe MXP with the new procedures) or because ATC requests, the rare times I planned for a standard decelerated appr I got the request to reduce 160, so I had to call gear down very far to manage my deceleration.... not really efficient |
Usually a little heavy, so the 160 to 5nm really does help manage the energy.
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Originally Posted by Smythe
(Post 10486292)
Usually a little heavy, so the 160 to 5nm really does help manage the energy.
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For somewhere particularly strict we use option 1 (LGW for example). 99% of the time we are stable at 1000ft but if not we can cotinue through 1000ft if we are in landing config and our speed is less than VAPP + 30 regardless of VMC / IMC. For other places I’d usually just manage the speed at 5 and then configure. |
From an ATC perspective can I say a big thanks to all of you that try and do achieve this. However there are a significant number of crews that fail and that can have a big impact on delays. An early speed reduction can cause a go around or at a single runway airfield, the loss of a departure slot. I’d rather have an arrival following arrival causing a go around because that type of trend will encourage the airlines to engage more with finding a solution whereas the extra 2 minutes of delay caused by loss of departure slot seems to get lost in the ATC delay mix. This problem is more(only?) apparent with A319/320 and A330. 160 to 4 non conformance league tables were introduced at a larger neighbouring airport and the problem has been almost eradicated, at least to the stage where it is now a one off occurrence rather than a fleet or airline trend. As an aside, the airline that requests 160 to 5 seems to be able to achieve 160 to 4 there. what we see on the radar when the aircraft (A319/320/330) is passing 4 dme; never 160 at 4, 152-159 (that’s good) 147-152 (average) 135-147 (two out of five aircraft) below 135 several times an hour and a few times a day there will be an aircraft at 118kts at 4 and 120kts at threshold! Another favourite is reducing from 180 to 160 as soon as established, even if that’s out at 12dme. I’ve given up filing ASRs, I could genuinely complete 20 per day for the very worst transgressions. Sorry for the rant and the thread drift but I think it’s important you all know how this affects you and how everyone else is doing. The next time you’re going round the hold for 20 minutes wondering the reason for the delay just imagine how much more consistent the movement rate could be if everyone flew the correct speeds. |
Latest Airbus position in case of 4nm 160kt is crossing 1000ft maximum speed Vapp+20 reducing to Vapp and stabilisation not later than 500ft. unless absolute regulatoryr for 1000ft stabilization.
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In the A320 series there's no problem with '160 to 4' if your company allows stabilization at 500.
The problem is to keep '160 to 4' ANDbe stabilized at 1000'. 'My' company recently raised the stabilization criteria from 500' to 1000' where stabilized means : Vapp + ldg config + spooled up engines. My method to achieve that is to be at 160, gear down, flaps 3 when approaching 4 DME and at 4 DME select managed speed + flaps full. |
Thanks DelPrado for the amazing input. It’s always great to read another point of view and the consequences. Regarding the 180 to 160, this is another I find a bit tricky. If requested maintain 180 obviously I comply. If given free speed it depends. On the the glide, if no traffic or no hint a speed reduction will occur I tend to keep 180ish until around 8NM. If I see there are many traffics sequenced or I listen traffic ahead are getting 160, I start reducing 160 just before the FDP (ie select F2 one/half a dot below the glide), this is because If I’m told at say 10/8NM reduce 160, at average weights or a A320SL the gear is the only way to get a prompt deceleration (fe sometimes at 8NM I push managed speed to decelerate and at 6NM I’m still close to 180). And flying gear down from 8/10NM is not so great.... |
@Del Prado: This problem is more(only?) apparent with A319/320 and A330. 160kts to 4nm is usually achievable, but it depends on conditions. Different companies have different Stabilisation criteria - some of which are more strict than others. Pilots try to avoid interviews with management as much as possible ! Airbus FBW have just four flap/slat configs between clean and full, Boeings have eight, so Airbus have to slow down for longer between configs. Less config obviously means less drag. The A330 and Sharklet A320s are very slippery. Fuel efficiency considerations obviously mean trying to use less thrust and less drag on approach. Going from 160kts at 4nm to Vapp (~135kts) at 1000’ can be tight if not at max configuration. Using speed brakes when partially configured on shortish finals is untidy and PF should have their inboard hand on the thrust levers by then and be concentrating on the tracking and the landing point. So an extended speed brake lever could get forgotten - a potentially dangerous situation.* *Yes, I know speed brakes should retract in Airbus FBW if TOGA is selected. |
Interesting discussion
Originally Posted by Del Prado
(Post 10486783)
160 to 4 non conformance league tables were introduced at a larger neighbouring airport and the problem has been almost eradicated, at least to the stage where it is now a one off occurrence rather than a fleet or airline trend. As an aside, the airline that requests 160 to 5 seems to be able to achieve 160 to 4 there. The larger neighbouring airport has reasonably flat terrain at both ends, whereas at everybody's favourite busy single (ish) runway airport there are some hills to the west. Combine that with some companies using 1000 AAL and others using 1000ft Radio Altitude as the stable criteria and you can start to see the issue. The terrain under the approach to 08R at Gatwick makes 160 to 4 and stable by 1000 radio very difficult to achieve. For 160 to 4 on a 3 degree ILS I aim to be 160 selected, F2, gear up. At 4.3 manage speed, gear down, flap 3, flap full and then it will almost always be stable by 1000 aal. In thermally conditions an extra half mile may be necessary. A319s at a light weight will struggle with this, so it all boils down to what the commander and the company consider acceptable. |
The engineering part of my brain has just wondered: why aren’t the speed brakes also deployed by the brake/rudder pedals when airborne? This would be useful when one wanted to use the speed brakes on a busy approach but didn’t really have enough hands ! - one would just use the brake pedals instinctively to slow down as one does in a car. This feature would be inhibited on the ground. I guess it might cause unwanted rudder inputs and might cause a problem in an EFATO if one used the pedals incorrectly. Sorry for the thread drift. |
Because speed brakes should not be instinctive especially at high altitude when slow (for ATC). Their effect of the min speed is marked and deployment is to be a conscious decision.
And how would the other guy know how much you're extending And you could hit the rudder by accident... I'm sure there's more! |
junction34 If there is a policy of stable approach based upon RAD ALT, it almost deserves to be violated.
Del Prado Out if interest, would there be a similar statistic WHERE is the point when crews stop maintaining 160? |
F3 160 selected until 4.5D, manage speed, then gear down, F full, landing checklist, stabalised at 1000 no problem. It doesn't always have to be F2 then gear. Use your drag devices as required, my 2c anyway.
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I drop the gear at 4.5 (with flap following when gear down) and then manage speed at 4 (as requested). Always configured by 1000’ aal and usually within Vapp +10 but as stated by some others in our company with 30kts is fine so long as you have Vapp by 500 RA. Yes it’s busy but perfectly manageable if youv’e discussed it beforehand. If there’s a tailwind then i’ll tell ATC and ask to slow down earlier. They’ve always been accommodating and would prefer that to someone doing so of their own volition, which seems to be the case a lot when you look at the stats |
I have gear and full flap out before 4.0 miles and only start to decelerate at 4.0 miles. Our stabilised approach criteria says on path, landing configuration, and checklist complete by 1000 ft. Speed commensurate with conditions. if your company policy is holding you back from not maintaining 160 to 4, identify the problem and get it fixed. The A330 even at max landing weight and a tailwind will be on speed and have thrust above idle before the minima. It is an unreasonable expectation to think other airlines should go around or hold longer because your company policy is holding up an efficient sequence. If everyone flew their assigned speeds exactly, and not this B/S 5-10 kts, or 1-1.5 no buffer (there is zero pilot buffer on ATC assigned speeds and distance) we would have less holding, and more landings per hour. |
Thanks for all the comments, lots of interesting points for me. If you start to slow at 4.2-4.5 you’re not going to lose more than 10kts by 4d and that’s fine, it’s the ones that start to reduce at 5.5 or more that ruin it for all. I understand the stability criteria and it must be very tempting to err on the side of caution but slowing early is not a ‘victimless crime’ at busy airfields and I’m surprised the airlines haven’t identified this as an area to improve and find a better balance between stability criteria, fuel burn/noise on approach AND landing rate. |
Airlines should reduce the stabilization height for 4nm 160 airports to five hundred feet. So it's not left to individual pilot in varying circumstances such as GW, winds etc. In case of1000 ft stabilization they should lay down a standard procedure. Be configured before 4nm with landing CL holding at flaps three. Crossing 4nm speed managed flaps full. You can expect to loose minimum 10 to 15 kts in next 1nm.
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For me it depends on how i started the Approach, if it’s all been well managed with full mental & cockpit prep to land i like to do the High speed App to set L/G down with speed managed after 4.5~5NM , in the contrary if its been a stressful flight with ****ty CPT or in long Night flight I rather to do it as slow as it can get with Flaps 2 at the FAF , the speed is under controlled after FAF Gears down and so on , so i think its all about the your situation and how you feel . Cheers ;) |
Del Prado I am really happy for your input here.
These would work on your side if implemented - although not realistic. Just a thinking exercise. - move the limiting point further, 4.5D - add a message to ATIS at peak times: "High flow rate. Keep assigned speeds strictly on final, lest wing-tip clearance is not assured." The second part is already on the tape at Heathrow :) - if somebody violates by more than 1,5NM, take them out of the sequence. Serious, twice in a single month and you will NEVER have that airline in your stats again. For the small Airbuses, there is an issue. Strict adherence to all historical 1000' criteria and LP/LD + fuel-saving (ehm, carbon lean, green ops) approach is not compatible with the 4,0D/160. Something has to give. If the incumbents devised a clever way that works on a large scale basis for them, it must be possible to propagate that to other operators. Infrequent visitors maybe not too much. Did you know, that apart from UK and FRA and AMS (cannot really recall anywhere else), the 180 knots restriction is never amended or lifted - unless separation critical? That pilots as a daily operating practice need to second-guess "how far do you want that"? |
This is an interesting topic. Having lived through all sorts of variations of speed requirements, stable approach policies (from ultra-strict to none at all) and aeroplane limitations/SOPs, I think it has got faintly ridiculous now. Many airlines’ SAPs are borderline incompatible with some airfields’ restrictions and aircraft end up being operated in a manner that is not really what you would call good airmanship in the widest sense.
Why do we try and fly stable approaches? Well, one reason is because the employer says so but more importantly, it allows a crew to monitor their aeroplane and the environment and react in a timely and appropriate manner to any issues. If large part of available capacity is used to make artificial gates that are sometimes mutually conflicting, there follows that there is much less capacity to assess and predict. I have been on flight decks where three or four pilots are so busy with the speed control and stability process that the proverbial gorilla could climb over the windscreen and no-one would see it, which is not a great place to be. Where is one of the worst places to encounter microbursts and/or windshear? Low level near an airport, so hanging on the thrust levers and speed brakes in an odd configuration approaching 1000R will mask some signs that things may be going wrong and if they do, make the recovery that much harder. IMO there needs to be a bit more joined-up thinking involving all stakeholders (I’m starting to sound like an exec.) and not having external requirements coming from different directions. In my airline we have a 1000R stable policy but you can legitimately bust that if it’s because of ATC speed control - where’s the sense in that? Nasty things can happen irrespective of whether you’re under speed control or not. |
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