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View Full Version : how do you manage your approach from T/D until touch down


hghazoly
8th Feb 2009, 21:42
i'm new 737-800 pilot with less than 11 hours on type
it is my first jet aircraft
i would like to know how to manage my descent from the T/D point until landing, just tell me how you do it ur way
any other info about the B737-800 will be appreciated
cheers :)

411A
8th Feb 2009, 22:44
Well....the usualy way is to do it the way your training Captain tells you, in accordance with standard company procedures.
Unless, these have been eliminated as a cost saving measure....:rolleyes::rolleyes:

bucket_and_spade
8th Feb 2009, 23:36
Have an idea of how many track miles your aircraft needs to descend in normal descent config (e.g. roughly 3 nm per 1000') and keep checking you're not getting high or low by checking this now and again (gross error checks) during the descent.

Set up the FMC with 'gates' - speeds and altitudes you'd like to be at at certain points. That gives VNAV the info it needs to plan a T/D etc. Plug in winds to the box to help it out and keep an eye on the actual wind during the descent and correct as necessary. When ATC step in and level you off/give you speeds etc. you'll no doubt revert to the more basic modes on the MCP (FLCH, HDG SEL etc.) - keep updating the magenta line to reflect what you're actually being asked to do as best you can and you'll have useful profile deviation info to work with. When you get close in, adjust your V/S as needed to try and achieve a continuous descent approach - use the range arc on your HSI to estimate when you'll level off at your cleared level in the MCP. Bear in mind you'll want track miles to reduce speed too (e.g. 1 nm per 10 knots).

That, or just keep the runway at the same place on the windscreen all the way down ;)

And, obviously, ask your training captains how they do it - that's the whole point of line training!

It's a combination of all of these things in reality - you end up taking info from all the sources on the aircraft and building of picture of where you are and where you want to be. I'm relatively new to it too - sometimes it works out well, sometimes not so well. Every day's a school day!

There's usually a lot of ways to achieve the same thing - if you want to increase your ROD you can speed up or use some speedbrake - if you're close in you might prefer to use speedbrake/gear/flap etc. as increasing speed increases your energy and it's speed you'll need to lose at some point! Just an example.

B&S

Intruder
9th Feb 2009, 07:20
Plan the "ideal" descent down to the last detail, but be prepared do what ATC tells you. Put the winds in the box, figure out the likely deviations from the planned arrival. Use VNAV when possible; FLCH or V/S when necessary or advantageous.

BelArgUSA
10th Feb 2009, 00:42
Amazingly, was able to plan TOD to touchdown without FMS...
Very rarely created a problem, despite wind and ATC changes.
I suppose that should a FMS fail, nowadays you declare an emergency...?
xxx
Really, NG (for 737) must mean "Nerds and Geeks"...
And SP (for 747) meant "Stupid Pilots".
Crying in memory of excellence of training in the past eras...
xxx
:{
Happy contrails

DBate
10th Feb 2009, 00:59
I suppose that should a FMS fail, nowadays you declare an emergency...?:) !

Honestly, I rarely use the FMS for my descent planning. As soon as you get a shortcut during approach (e.g. during the transition to one of the runways in FRA), you might end up way too high if you had followed the FMS, which calculates your descent based on what you entered - usually the whole transition.

Have an idea of what to expect during the approach, pay attention where ATC turns the other aircraft onto final, and - most important and already mentioned by others - pay attention to what your training captain says (with the experiance you have on type, the training captain should be your first and preferred source of information. Come back for more later ;)). He should know. The rest will come with experiance.

Have fun,
DBate

GlueBall
10th Feb 2009, 07:41
With only 11hrs on type you ought to hand fly from TOD to touchdown so that you get a feel of the jet; practice to fine tune your skills to effect a smooth descent profile without jerking the airframe. It's what you have to do when the FMS goes on vacation; it's what you have to do when the controller takes you off the STAR [just as you've plugged in the very last detail of the entire anticipated profile] then gives you an immediate new heading, followed by more impromtu headings and altitude changes and speed reductions, . . . and changes your arrival runway all at once, then clears you for a visual on a runway where the ILS is out of service.

yowdude
10th Feb 2009, 11:17
since you're new to the jets , be at fl180 by 60nm of your target destination unless other local constrains are in place.

you'll never be too high or too low for the approach

bucket_and_spade
10th Feb 2009, 12:18
May I be so bold as to say there's an undertone of (good-natured? :)) disgust at using the FMS to plan a descent in some posts.

Don't get me wrong, I FULLY AGREE that you shouldn't need it (and I don't) but it is there as a great resource for 99.99% of the time on the type the original poster is flying and, at a quiet airfield with little ATC intervention, it is great at planning an efficient, continuous descent for minimum fuel burn, taking into account it's extensive knowledge of the aircraft's performance, minute to minute.

As I allude to in my first post, the FMS is a great tool on the a/c the poster flies and making use of all resources is surely what every good pilot should be doing? I don't rely on the FMS though, hence the ballpark figures/rules of thumb that everybody mentions always being at the back of my head. In my humble opinion, as long as you don't end up blindly following the FMS and have made the effort to learn exactly what it's trying to do at every point, it can only enhance your situational awareness and not detract from it.

A bit of book work learning about exactly what the FMS is trying to achieve in each mode/phase gives you a great overview of the way Boeing obviously suggests things should be done on a particular type and is an invaluable grounding on which to add some finesse yourself.

bucket_and_spade
10th Feb 2009, 12:21
Rainboe,

Good point about the training - my experience has been that a lot of the really useful stuff has been self-taught by looking at the manuals/just thinking it through. Descents are definately an area where there wasn't a huge amount of info imparted by the type ground school and the trainers. I think it's assumed that you'll pick it up by osmosis with exposure!

B&S

Rainboe
10th Feb 2009, 13:41
You do pick it up by 'osmosis' (my God, I should be charging for it!), but with 11 hours on type, the FMS is the first thing you don't even touch! Fly it like a Cherokee- learn to get to know the performance. The FMS only gives you out as good as you program in! He shouldn't be programming, he should be flying and looking out of the window! How did I learn to fly a VC10 and 747 without using those things?

When he learns how to fly the plane and what he can do, then he can learn the refinements. But it's frightfully depressing to think a newbie learns to program a bloody computer first and then slavishly follows it first without developing his first ideas of his own!

I barely look at the FMS in the descent. I have my own idea what the descent should be like and I follow that, which is just as well because the descent calculations in the 737 are awful, and you can frequently spot errors of up to 5-7,000', which suddenly correct themselves. Below 10,000', I am just totally uninterested in it. I know how I am going to fly the approach, and I can allow for shortcuts or my own speed control. This is what he should be learning, not slavishly following a dodgy computer calculation. If he follows FMS and gets held up, or extended, his 'picture' will crumble. Then what does our young Biggles do?

All I would say he should do is draw rings at 10/30/100 miles and use it for nothing else.

RoyHudd
10th Feb 2009, 18:33
Rainboe's right....FMS just needs tidying up below 10000ft, and that's done by PNF on order of PF.

Mind you, looking out of the window below ten hasn't been much help these last few weeks in the UK! But visual skills are essential everywhere for weather avoidance, and terrain avoidance too, especially when heading for Greek Islands, Egyptian/Turkish destinations, and most long-haul beach fields....along with use of terrain map and/or radar. And keeping an eye on TCAS to see what others are up to. And listening to ATC commands to other traffic. And monitoring w/v too. Quite a lot to think about along with flying the aircraft, but not playing with the FMS!

Northbeach
10th Feb 2009, 21:25
Congratulations on your new job flying the 737-800, getting through training and out on the line. Now the real work (and fun) begins.

Three things stand out in your post. First is “it is my first jet aircraft”; this pilot is new to jets and may have limited, or virtually no experience, flying above FL180. Secondly “I’m new 737-800 pilot with less than 11 hours on type”; he/she is cutting their teeth on a complex high performance next generation platform. And finally is the location “Egypt”, so this pilot is either a very fortunate expatriate or a low time national, I suspect the latter.

I am not sure what the flight deck culture is like where you are flying but I would encourage you to speak up and ask the Captains you are flying with for advice. They should be eager to tell you what they have learned. Listen to what they say and watch how they fly, then copy the Captains you would like to be like in a few years. By all means follow the training department’s and the SOP’s guidance. Ask other pilots who are already there what works for them (both Captains and First Officers).

On the NG (737-800) at 30 miles from your destination, and closer, the landing gear is your friend while descending. Drop the gear early to increase the drag will help you get down if you need the help. The jet is so clean that the first several degrees of flaps really don’t to all that much-get the gear down early it can make a big difference for you.

As others have stated, have some parameters set in your mind. What altitude do you need to be at 60, 30, 15 NM from the runway? Make sure you hit those altitudes 60, 30 & 15 NM out and it will make the whole descent much easier.

Are you familiar with the 3 to 1 descent profile? Do you know how to modify the 3 to 1 descent profile for ground speed variations? Are you comfortable with whatever level of training you were given on the FMS to understand what the vertical path is and how it differs from vertical speed?

If you don’t know what a 3 to 1 descent profile is PM me and we will talk about it. My own method is no better than somebody else’s method but it works well for me.

framer
10th Feb 2009, 22:06
1/ Determine a method for knowing the track miles to run (prog page or DME or rings on the EHSI)
2/ Start your descent at 3x +10nm
3/ Constantly monitor the 3x profile and if it gets to be exactly 3x profile then use speedbrake to get back to about 3x +5.

Just do that for a month or so until you start to get a feel for the a/c then you can start to manage it a bit more efficiently.

There really are a lot of variables that you will get used to and at some stage during the flight it is going to have to come back onto a 3x profile but that is normally between 4000 and 3000ft .

eg if you are at 30,000ft start your descent at (30x3 +10) 100nm
at 25000ft you might be at say, 81nm to touch down, so you would think to yourself "a-ha! I'm at 3x plus 6 therefore I'm slowly getting higher"
If you then find yourself at 20,000ft and 60nm you could bring out the speedbrake so that at 15,000ft you are at 50nm. etc etc etc.
I know there are going to be responses to this saying "no no don't ever use your speedbrake blah blah blah" but when you are just learning I reckon it's a good tool if things are starting to get away from you.

Summary; start at 3x +10
keep it between (3x+10) and (3x+5)
at 4000ft use the slow down to bring it onto a 3x profile:)

greenslopes
10th Feb 2009, 22:34
Good post by many. Three times profile works a treat. The classics(bless em) fly a much better "Path" than the NG's do(if left in LNAV/VNAV). Having said that if you are going to leave it in LNAV/VNAV then have a look on the descent page and the most limiting height/speed will be highlighted, look below the highlight and it will display the required rate of descent to achieve the required height and speed. If this rate of descent is not being achieved then do something about. This may be LVL CHNG,V/S or even the addition of thrust to a steeper than desired path.
But most of all ask lots of questions, most pilots really appreciate someone who is willing to ask and learn.
Oh, and don't forget the 737 is a tractor and deserves to be driven as such(oh how i miss the F-100!!).
But most of all..................enjoy!

The Real Slim Shady
12th Feb 2009, 00:50
Rainboe has it.

Below FL100 do not touch the FMC: besides it only understands 1s and 0s as it is a computer. It doesn't have the nuances a pilot has.

Choose an arbritrary point somewhere along your inbound track as a 4 pane window: the ideal position is on speed, on altitude at the intersection of the horizontal and vertical window bars. If you are in the top left pane, high and fast, you have a problem. If you are in the bottom right pane, low and slow, you have a problem, if you are high and slow or low and fast, you have ENERGY that you can convert.

Think Groundspeed: divide GS by 2 and multiply by 10 or if you can just multiply by 5 for the ideal ROD. If you are doing 400kts GS you will need 200fpm to maintain the 3 degree slope. Reduce that to 150kts and the required ROD changes to 750fpm.

Think wind. What will happen to my GS and hence ROD when I turn base, establish on final etc.

DBate
12th Feb 2009, 00:59
If you are doing 400kts GS you will need 200fpm to maintain the 3 degree slope

I don't want to appear picky, but you forgot a '0' there my dear colleague ;).

A Comfy Chair
12th Feb 2009, 12:55
Just work out some "Gates" that you want to be in, and work from there.

Over time you'll learn to tidy it up a bit (I'm quite new on my current type, and so still adjusting to it too, so I know how you feel!).

The most important one that I need on the 767 is 250kts at 5000ft with 20 track miles to go. (Thats the track miles I think I'll fly, not necesarily what the FMC says). If i'm there, I know i'm set. If I'm at 6000ft, then I'm 1000ft high, and can correct that accordingly. Same goes for speed.

Others some people use are 30nm @ 8000ft and 40nm @10,000ft. After that, its a case of getting a feel for things.

Just be conservative to start with, and if its looking nasty, get the gear down :} Gear solves everything.

CamelhAir
12th Feb 2009, 13:17
Forget the FMS to plan anything until you can fly the aircraft without it.
Start descent at 3*FL in NM. While you're still getting to grips add 10NM for slowing down. So starting at FL350, start descent at 115NM. Don't forget to correct for airport altitude, non-standard QNH and, finally, adjust for wind. Add a few miles for a strong tail wind and subtract for a tailwind.
Then, as others have mentioned, use "gates" to make sure you're on profile. For example, decide what FL you want to be at every 20NM or so.
Finally, to maintain a 3deg descent you need to descend at 5*GS. So if you start descent at 115NM from F350, with a GS of 450kts, if you fly a VS of 2250fpm you will be at F300 when 90NM out etc etc. If you continually adjust your VS to maintain 5*GS you won't be caught out by varying winds.
And when you can do all this competently without reference to the FMS, then use the FMS.

BelArgUSA
12th Feb 2009, 13:56
My "planning" was the same in all types I flew.
They were 707, 727, 747 and DC8...
No difference in speeds nor techniques.
I just recall, these darned DC8-70 (CFM) were hard to slow to 230 KIAS.
That is to get flaps and gear...
xxx
Our friend B&S said -
Descents are definately an area where there wasn't a huge amount of info imparted by the type ground school and the trainers...
Too bad your airline did not call upon me... classroom or line training.
xxx
Basic profile (all jets) is...
3 x NM track distance for start of descent.
Example, FL350, start descent 105 NM out.
xxx
Wind factors -
If strong tailwind at level, start descent 20 NM earlier.
If strong headwind at level, start descent 20 NM late.
xxx
Generally speaking, try to be...
FL300 when 90 NM out.
FL200 when 60 NM out.
FL100 (10,000 ft AGL) when 30 NM out, at 250 KIAS.
5,000 ft AGL, first flaps selection. Reduce speed accordingly.
xxx
If straight-in ILS expected, start 10 NM early.
If circle-to-land - start 20 NM late.
Use 320 KIAS as basic planning speed, for most types is OK.
Plan on 2,500 FPM rate down as standard.
If getting too low, reduce to 300 KIAS, about 2000 FPM rate.
If getting to be above profile, go to VMO and 3000 FPM.
xxx
Airplanes with large landing mass difference... like 747 -
Heavy aircraft, as many cargos are - start 10 NM early.
Light aircraft, partial passenger load - start 10 NM late.
xxx
Try to combine all of the above - and forget you FMS...
My 747s got fitted with FMS in 2001.
Using the FMS for profile did not change the fuel burn statistics.
They just were wonderful for navigation and waypoint planning.
Nothing that the LTN-92 INS could not handle.
In other terms, lots of wasted money and 25 kilos of mass increase.
But young F/Os adore little knobs to push...!
xxx
:rolleyes:
Happy contrails

Mungo Man
13th Feb 2009, 10:24
handflying - it's what you have to do when the controller takes you off the STAR [just as you've plugged in the very last detail of the entire anticipated profile] then gives you an immediate new heading, followed by more impromtu headings and altitude changes and speed reductions,

I'm all for visual approaches but why oh why advise a newbie with 11 hrs jets to hand fly when getting impromptu headings?!! Just use an appropriate vertical and lateral mode on the autopilot flight guidance panel.Save yourself some capacity to monitor what is happening.

As for descent planning, 3 times the altitude in 1000s of feet, plus a bit for tailwinds, take you time and refine it when you get a few hundred hours experience. Ask Captains for their tips, tricks and words of wisdom.