787WannabePilot

Disc A/P @ 1000 feet for landing... tips?

Recommended Posts

I have started disconnecting the A/P at approx 1000', rather than 500' as I was doing it before to get a bit more practice.

However, unless my weather settings are wacky, I am getting bounced all around. I use the HGS, but I find I am 'chasing the target' quite a bit.

Any advice?

Share this post


Link to post
Share on other sites
Help AVSIM continue to serve you!
Please donate today!

1 hour ago, 787WannabePilot said:

Any advice?

Kick the AP off even earlier to develop the stick and rudder skills necessary to accomplish what you're looking for. You're not giving yourself much time to develop those skills, which is why you're behind the plane and chasing things.

  • Upvote 2

Share this post


Link to post
Share on other sites
1 hour ago, 787WannabePilot said:

I use the HGS, but I find I am 'chasing the target' quite a bit.

That is a very common problem during the learning stage.  Change your focus to the aircraft attitude symbol and move it such that you set up a trend that follows the FD circle.  This should mitigate some of the over controlling you are doing. Don't worry about keeping the circle inside the boresight all the time, the trend is more important.  A good place to disconnect A/P and A/T is when you are stabilized (flaps in landing position, speed on target), which might be anytime after FAF until 1000 AGL (you should always be stabilized by 1000)

  • Upvote 2

Share this post


Link to post
Share on other sites

On your way in use the HUD and the flight path symbol to help you know where the plane is headed.

However if you are manually landing the plane, you should mostly be using the things on and around the runway as guidance to land (probably why until you see the runway, you shouldn't be in manual mode yet). You should not be following the guidance cue to tell you where to land, you should be using the runway tell you where to land.

I find the FD circle useless on approach.

Use automation to achieve a stable approach, then disconnect. Don't disconnect until after you are stable. Sometimes it takes more time, sometimes less. Usually it happens around 1500 feet, but it varies depending on conditions. For this reason the ideal time to disconnect varies.

During the approach the flight path symbol in the hud helps me generically figure out where I am headed after I disconnect.

As I get closer, the runway centerline tells me where I want to be horizontally, and the VASI lights tell me where  I want to be vertically

 As I get closer still, the runway markings help guide me in the rest of the way. Crossing the apron look up at the horizon and plant it down as you see fit depending on conditions.



 

Share this post


Link to post
Share on other sites

Typically a 737-800 is going to be about one minute and twenty seconds from touchdown when at 1,000 feet AGL, and it will have only just got the gear down a few seconds before that, when at around 1,500 feet AGL. It would typically be slowing down from about 160 knots to around 130-125 knots for coming in over the numbers, so you're not really leaving enough time to get a feel for how the thing is flying if you are tripping the autopilot off at that point, since it is right in the middle of a 30 knot deceleration. Having done so at 500 feet previously, the thing was probably already so stabilised at close to the landing speed, so that all you had to do was ride it in and flare at the right moment, but from 1,000 feet when it's still dropping from 160 knots on its extended final down to 125 knots or so for its final ride in and the gear coming down has affected the necessary throttle setting, is what is making life hard for you.

Theoretically if it is reasonably well trimmed, you shouldn't need to do that much to hold it on course and descent, but the fact that you are going to be slowing down by about 30 knots from that point to crossing the threshold means it won't just sit in the pipe without any control inputs at all like it probably would do from 500 feet when the autothrottle and autopilot has done all the work already. So that's where the problem lies; you're too late on the controls to be having a good feel for what throttle and pitch settings are necessary when taking over at 1,000 feet AGL, and without a good feel for hand flying behaviour, you'll tend to make mistakes, not critical ones, but enough to prevent a smooth transition to manual control for a nice landing. You'd be far better off taking it off autopilot at around 3,500 feet when you are just about turning for the localiser. Then you'll know what it is flying like at about 160 knots and what throttle setting is holding it there.

Concentrate on 'flying the needles' on the PFD right out from 3,500 feet, as this will give you a good idea of the trend for any descent or climb for a given pitch and throttle setting, and from that you'll see that if you arrest any trends early, you shouldn't really have to move the yoke too much at all in terms of pitch corrections and will have a good idea of what throttle setting you'll need to get to the reference landing speed. Don't try and smooth out every bump, an airliner like the 737 has a lot of momentum, thus it will ride through bumps and keep an average direction, so don't fights those bumps, just let it ride down that ILS glideslope line and use small amounts of power and pitch changes to keep it there, gradually dropping down to a stable final approach speed.

Three or four goes at that and you'll have it sussed. Oh, and don't use too much flaps unless you really need to, especially in windy conditions, that makes the power adjustments necessary to keep it on the glideslope occur over a wider range because you have to overcome the drag from the flaps.

  • Upvote 1

Share this post


Link to post
Share on other sites

I normally have the aircraft stabilised by 1000ft. I find if the gear is out and the final flap setting is set, then the aircraft thrust and descent rate is pretty established and you only need to make very minor adjustments after disconnecting the AP.

 

Then i ignore instruments, bar airspeed of course, and concentrate on the  VASI and most importantly, when looking at the runway don't just focus on the piano keys, look down the whole runway, you will get a better picture of what the aircraft is doing regarding drift etc.

 

 

 

 

Share this post


Link to post
Share on other sites

Hand flying at 1000 ft is plenty of time to get a feel for the airplane.

A good rule of thumb is to be stable, configured and on vref at 1500 AGL. If you hit this target, by the time you are taking it off autopilot at 1000 feet, the airplane should be at the proper pitch and power.

From here, just make small changes. Don't over control. Small changes go a long way when your flying at 140-150 knots.

Same with thrust. You shouldn't need to go above 5% n1 changes. This will cause you to destabilize the approach which will throw everything off.

The FD is going to be moving around because it's following an ILS.

Just remember, small changes.

 

Share this post


Link to post
Share on other sites
5 hours ago, ahsmatt7 said:

A good rule of thumb is to be stable, configured and on vref at 1500 AGL.

ATC at major airports are gonna love your 737 tootling in at Vref whilst still four miles from the threshold at 1,500 feet with a big queue of airliners all at 160+ knots up your tailpipe being told to go around lol.

  • Upvote 2

Share this post


Link to post
Share on other sites

Well, considering that ahsmatt7 is a real world airliner pilot, I get the feeling that he knows what he is talking about! My input here is probably pointless (since I currently fly in totally calm conditions), but I am generally on the glideslope and stabilised way before I get down to 1000 feet, so landing the plane manually from there is a piece of cake :wink:

Share this post


Link to post
Share on other sites
8 hours ago, Chock said:

ATC at major airports are gonna love your 737 tootling in at Vref whilst still four miles from the threshold at 1,500 feet with a big queue of airliners all at 160+ knots up your tailpipe being told to go around lol.

I fly King Airs and its always fun when they tell you to keep your speed up in that thing going into a major airport. But that is better than getting the "Turn right 90 degrees and climb to..." call because you are too slow. I know its your approach once cleared, but in practice it doesn't work out that way.

Share this post


Link to post
Share on other sites
8 hours ago, Chock said:

ATC at major airports are gonna love your 737 tootling in at Vref whilst still four miles from the threshold at 1,500 feet with a big queue of airliners all at 160+ knots up your tailpipe being told to go around lol.

In IMC, approach isn't going to assign a speed to maintain to a point closer in than the marker (on an ILS).  Typically,  that's at least 5nm out.  It would actually be unusual not to be slowed to roughly target speed by 4nm out.  I'm not saying it can't happen and still qualify as stable,  but it isn't typical.  Slowing at the marker is certainly not going to force a go around for following traffic unless they're too close to begin with. 

  • Upvote 1

Share this post


Link to post
Share on other sites
2 hours ago, Stearmandriver said:

In IMC, approach isn't going to assign a speed to maintain to a point closer in than the marker (on an ILS).  Typically,  that's at least 5nm out.  It would actually be unusual not to be slowed to roughly target speed by 4nm out.  I'm not saying it can't happen and still qualify as stable,  but it isn't typical.  Slowing at the marker is certainly not going to force a go around for following traffic unless they're too close to begin with. 

Probably not in IMC, but that wasn't part of the OP's issue. What I can tell you is that at my local EGCC (Manchester Int'l), I'd put money on the controllers there telling you to expedite if you're at Vref when still four miles from touchdown.

Of course I know it was only a rule of thumb to be saying Vref that far out, in order to help out the OP with sussing out how to stabilise for an approach, so it's no bad thing in a sim to be suggesting that when we don't have to really concern ourselves with traffic spacing except maybe on Vatsim or some such. After all, we can do what we like in our PMDG 737s, since there really is no ATC to upset and who cares if those AI traffic airliners get sent around? so my comment was obviously a bit tongue in cheek, hence the 'lol' on the end of it which a few people appear to have missed. But joking aside, interestingly, I just tracked the speed of a Dornier 328 coming in to 23R at Manchester, with nothing behind it so no real reason to be pouring the sauce on, but even that thing was still doing 150 as it passed through 1,000 feet.

Share this post


Link to post
Share on other sites
1 hour ago, Chock said:

I'd put money on the controllers there telling you to expedite if you're at Vref when still four miles from touchdown.

They can ask all they want but when it comes down to it the aircraft behind me is their problem, not mine.

Share this post


Link to post
Share on other sites
1 minute ago, JoeDiamond said:

They can ask all they want but when it comes down to it the aircraft behind me is their problem, not mine.

Yup, that is absolutely true, it is indeed the problem of the controllers to provide adequate spacing for anything they clear for a line up, or any other steering direction for that matter, but it's probably not going to win you many friends in the tower if you don't do things in a suitably expiditious manner which fits with the general rhythm of operations.

Share this post


Link to post
Share on other sites

I take my cue from the flickdeck to sim guy, who is a real Boeing 737 pilot....4nm out, drop gear and go flaps 15, so by then one wouldn't be at Vref yet

Share this post


Link to post
Share on other sites
58 minutes ago, Chock said:

Yup, that is absolutely true, it is indeed the problem of the controllers to provide adequate spacing for anything they clear for a line up, or any other steering direction for that matter, but it's probably not going to win you many friends in the tower if you don't do things in a suitably expiditious manner which fits with the general rhythm of operations.

Perhaps things are done differently on your side of the pond.  In the States flying from Vref from the FAF inbound is entirely normal, VMC or IMC.  We are required to be fully configured by 1000 AFL so dropping the gear four miles out is cutting it a bit close.  Stabilized approaches are a big thing over here.

  • Upvote 2

Share this post


Link to post
Share on other sites
7 minutes ago, JoeDiamond said:

Perhaps things are done differently on your side of the pond.  In the States flying from Vref from the FAF inbound is entirely normal, VMC or IMC.  We are required to be fully configured by 1000 AFL so dropping the gear four miles out is cutting it a bit close.  Stabilized approaches are a big thing over here.

Yeah, you have to always keep in mind that their controllers, for some reason, are required to maintain sep at all times for you. Over here, once you call traffic in sight, you're the one who maintains the separation with the controller providing supplementary corrective action (you choose your speed, and if the controller senses danger, they'll ask you to change the speed or send you around, etc.). Over there, it's positive control at all times, even when you're visual...for...reasons that someone will likely blindly attribute to 'safety' since you can't ever argue with 'safety'...then you'd be anti-safety, and you aren't anti-safety, are you?

This is also why they magenta line from DEP to DEST - it's easier on the controllers to provide the aforementioned control, and really helps out the CFMU run all of its calculations (the latter makes sense, given the amount of coordination between the various control centers in each country and in Maastricht).

Share this post


Link to post
Share on other sites
11 minutes ago, JoeDiamond said:

Perhaps things are done differently on your side of the pond.  In the States flying from Vref from the FAF inbound is entirely normal, VMC or IMC.  We are required to be fully configured by 1000 AFL so dropping the gear four miles out is cutting it a bit close.  Stabilized approaches are a big thing over here.

Yup, that could indeed be the case, and of course there are airline-specific procedures too. I've kind of got the impression that the cheapy airlines (i.e. Ryanair and Easyjet) are telling crews to get it all done a bit later on approach so they're not using high thrust settings on a long final to overcome the drag of the dunlops and landing flaps for any longer than feasible.

Share this post


Link to post
Share on other sites
15 minutes ago, scandinavian13 said:

Yeah, you have to always keep in mind that their controllers, for some reason, are required to maintain sep at all times for you. Over here, once you call traffic in sight, you're the one who maintains the separation with the controller providing supplementary corrective action (you choose your speed, and if the controller senses danger, they'll ask you to change the speed or send you around, etc.). Over there, it's positive control at all times, even when you're visual...for...reasons that someone will likely blindly attribute to 'safety' since you can't ever argue with 'safety'...then you'd be anti-safety, and you aren't anti-safety, are you?

lol... I love it how you express your endorsement with our admired control freaky EU :D

:laugh:

Share this post


Link to post
Share on other sites
1 minute ago, Chock said:

I've kind of got the impression that the cheapy airlines (i.e. Ryanair and Easyjet) are telling crews to get it all done a bit later on approach so they're not using high thrust settings on a long final to overcome the drag of the dunlops and landing flaps for any longer than feasible.

Noise (on the ground) is also a factor, plus 160 kt to 4DME (~1200ft aal) is a very common speed restriction. No ATC speed control is permitted inside 4 DME (UK).

I can't think of any airline that wouldn't encourage its pilots to fly the aircraft as efficiently as is safely possible in whatever conditions prevail and in my experience most airline pilots I know pride themselves on using their skill and experience to ensure a safe and efficient flight without any unnecessary delays, wastage of fuel or creating excessive noise on the ground -- that is, after all, part of the commercial responsibility an airline pilot has. Thus, sure, they will aim to fly CDAs and avoid flying excessively conservatively (i.e. dragging it in level for miles and miles with gear, flap and loads of thrust on). That said, all airlines have strict stable approach policies and these usually take the form of a mandatory requirement to be fully configured, on speed, on path and with engines spooled and all checklists completed by 1000ft aal. This is tight but generally doable with a 160 to 4 restriction. Some may permit some latitude (generally around speed -- something along the lines of "speed within X knots of Vref and reducing, provided all other criteria are met") at 1000ft in VMC in which case the 'hard' gate will be at 500ft where if you haven't got the speed back and engines spooled a mandatory go around must be flown, but from what I hear the trend is very much towards insisting on being fully stable in all cases by 1000ft whether IMC or VMC.

I am almost certain that is the case at Easy, and being something which can be very easily monitored there is almost nil chance of a crew knowingly continuing without meeting the stable criteria as the aeroplane will be telling the OFDM department about it literally as soon as the wheels hit the runway. Runway excursion is a perennial safety topic and almost every such incident follows an approach that didn't meet the stable criteria, so to my knowledge the airlines are exceptionally hot on monitoring compliance.

Share this post


Link to post
Share on other sites
16 hours ago, Chock said:

ATC at major airports are gonna love your 737 tootling in at Vref whilst still four miles from the threshold at 1,500 feet with a big queue of airliners all at 160+ knots up your tailpipe being told to go around lol.

Yeah your right, I don't know a darn thing about this stuff even though I'm based at one of the busiest airports in the world.

Give me a break....

Besides, most if not all airlines require you to be stable and configured prior to the FAF. Or 1000 ft on a visual.......most airlines.  stable doesn't mean just starting to get the airplane in the final landing config.....it means already in the landing config, on speed and without any large thrust or pitch changes needed.

These are usually around 5 miles out.

 

Also, you do realize that controllers space airplanes out accordingly to allow for everyone to slow down at the FAF?

I'll throw you a bone though....ill correct myself, be stable by 1250 ft.

Share this post


Link to post
Share on other sites
38 minutes ago, ahsmatt7 said:

Yeah your right, I don't know a darn thing about this stuff even though I'm based at one of the busiest airports in the world.

Give me a break....

Didn't say you don't know anything about it, that's hardly likely to be the case for someone with an ATP ticket. I was merely pointing out that it's not really going to be acceptable to be at Vref when still four or five miles out when a lot of traffic is coming in. Of course yours was a general comment to help the OP, which is why I stuck lol on the end of my comment in relation to it.

Anyway, hopefully the Robert (the OP) is taking the overall gist of the many replies on this thread about what is necessary to avoid the tendency to over-control, i.e. chasing the needles, rather than addressing the trends.

Share this post


Link to post
Share on other sites
Just now, Chock said:

Didn't say you don't know anything about it, that's hardly likely to be the case for someone with an ATP ticket. I was merely pointing out that it's not really going to be acceptable to be at Vref when still four or five miles out when a lot of traffic is coming in. Of course yours was a general comment to help the OP, which is why I stuck lol on the end of my comment in relation to it.

Anyway, hopefully the Joe (the OP) is taking the overall gist of the many replies on this thread about what is necessary to avoid the tendency to over-control when chasing the needles rather than addressing the trends.

My apologies....the lol made it come off as arrogance. Makes a lot more sense now.

Share this post


Link to post
Share on other sites
1 minute ago, ahsmatt7 said:

My apologies....the lol made it come off as arrogance. Makes a lot more sense now.

Nah, the 'lol' was me visualising a plane coming in at just above stall with a bunch of 747s up its back end, not your comment, I'm sorry if you thought it was directed at you, it certainly wasn't the intention. That's the trouble with the internet, some stuff just doesn't translate. Anyway it's all grist to the mill, so long as the OP gets his runaway jet under control, it'll be mission accomplished.

Share this post


Link to post
Share on other sites
18 minutes ago, Chock said:

Nah, the 'lol' was me visualising a plane coming in at just above stall with a bunch of 747s up its back end, not your comment, I'm sorry if you thought it was directed at you, it certainly wasn't the intention. That's the trouble with the internet, some stuff just doesn't translate. Anyway it's all grist to the mill, so long as the OP gets his runaway jet under control, it'll be mission accomplished.

Heres something to laugh at.

In the summer, everyday around 2 to 3 pm. There's a cirrus thst comes into ORD. Talk about clogging things up.

It's a sight to see.

It's all water under the bridge! Thanks for clearing every thing up. Once again, my apologies for snapping at you.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now