airernie

Approach to landing.

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I am currently flying the FeelThere E175, but this really applies to all of the big jets I have.

I attempt to fly using STARs, but using LNAV/VNAV I frequently find that the plane takes a wide turn when entering the approach course and by the time it's on course I'm high.   I am then faced with a go around, or manual dive to get to the appropriate altitude.

One solution I have used is to lengthen the point at which I intercept the approach course to compensate for the turn, but not sure if that's how others do it.

When flying VATSIM this in not an issue because the controller insures that I'm at the correct altitude.  However, VNAV doesn't have human smarts.

So, I guess that I'm asking is how others deal with this issue.

Thanks,
Ernie

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What is your speed at intercept Ernie?  That can make a difference. Not just Indicated, but also often overlooked groundspeed.

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Have you also got the bank angle restricted? On some airliners you can select the bank angle from 5 to 25 degrees I believe, or leave it in auto. If the plane is only making a turn with 5 degrees of bank then that may widen your turn.. a lot.. :)

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1 hour ago, clipper759 said:

What is your speed at intercept Ernie?  That can make a difference. Not just Indicated, but also often overlooked groundspeed.

Good point.  I usually leave it up to the FMC, but it's usually between 150 to 200 IAS, but seldom pay attention to what my GS is.  That is something I guess I need to be more aware of.

I try to insure the FMC agrees with the charts, but not really sure what I should be shooting for when I intercept.

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43 minutes ago, HighBypass said:

Have you also got the bank angle restricted? On some airliners you can select the bank angle from 5 to 25 degrees I believe, or leave it in auto. If the plane is only making a turn with 5 degrees of bank then that may widen your turn.. a lot.. 🙂

Thanks,

When given the option I leave the bank angle along, but I don't think the E175 gives that option.

Something else I need to look into.

 

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Strange.... 

Is the approach and transition entered correctly? 

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1 hour ago, LewisW296 said:

Strange.... 

Is the approach and transition entered correctly? 

That's actually my problem. Trying to get the aircraft to correctly enter the final approach leg.

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ernest

how about a few examples of the particular arrivals where you have the "issue" ...... could help with the guessing.

 

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8 hours ago, vadriver said:

ernest

how about a few examples of the particular arrivals where you have the "issue" ...... could help with the guessing.

Here are a couple of images that illustrate the problem that I'm having. 

The first is KJAX-KMIA- HILEY7, ILS27.  The second KLEX-KATL-CHPPR1, ILS27R  In both case the turn to approach is rounded and by the time I hit the final approach point (HENDN or YOUYU) I am too far above the suggested altitude.

HENDN is particularity a problem because the next step is GS1700 and the FMC doesn't descend the aircraft fast enough to hit it.

zZhxfrf.jpgKLToptY.jpg

 

 

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Hi Ernie,

The main thing to say is that VNAV or no VNAV, ATC or no ATC - there is only one person ultimately responsible for navigating the aeroplane in both lateral and vertical dimensions and that is you!

VNAV is a useful tool which can be a great aid to a safe and efficient flight but it is not infallible (in fact, anything but). The golden rule at all times is that if the automatics are not doing what you want, change something - you put the aeroplane where you want it, don't just sit back and watch the automatics fly it somewhere else!

I am not familiar with the E-Jet so I am not sure precisely what modes are available but in general you can think of there being three levels of automation:

  • The full, all-singing advanced LNAV/VNAV modes which will manage lots of things for you
  • Basic modes such as Heading Select, V/S or FLCH
  • Manual flight

If VNAV isn't giving you what you want, drop in to a basic pitch mode like FLCH or V/S and put it right. Make sure you are monitoring your progress all the way along the descent: flying a slippery, high-inertia transport-category jet is like driving an articulated lorry compared to a go-kart: you can't just stop/change direction etc on demand. You have to think ahead, anticipate and make corrections and adjustments early before the situation develops further. As you have discovered, if you wait until you have already got high on final to start doing something about it, it is much too late!

A simple rule of thumb to monitor your descent is to multiply the track miles to go by three to give the height you ought to be above the runway (e.g. 10 miles to run = 3000ft, 20 miles to run = 6000ft etc). Remember that airspeed is a factor as well (as it is an energy problem so the faster you are the lower you need to be at a given distance in order to lose the speed).

In the cruise, think about the 'gates' you want to hit at various points on the approach. A good starting point might be:

FL200 - 66nm to run at FMC ECON descent speed (say roughly 280 KIAS)

FL150 - 50nm to run at FMC ECON descent speed

FL100 - 33nm to run at 250 KIAS

6000ft - 20nm to run at 250 KIAS max

3800ft - 12nm to run at 210kt/min clean speed max 

2500ft - 8nm to run at 180kt max with some flap extended (depending on aircraft type, maybe Config 1 in an Airbus, Flap 5-15 in a Boeing etc)

1500ft - 4.5nm to run at 160kt max with gear down and approach flap selected (say Config 2 in an Airbus, Flap 20 in a Boeing)

1000ft - 3.5nm to run at final approach speed and in landing configuration (gear down, landing flap set etc).

As you descend make sure you are hitting the gates and if it looks as though you are going miss on take action - select speedbrake, change to a mode that will give you a higher rate of descent (FLCH etc for instance) and so on. Keep measuring your progress and take positive action to put the aeroplane where you want to it to be.

Remember - you are the PIC so don't be a passenger!

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22 hours ago, airernie said:

Trying to get the aircraft to correctly enter the final approach leg.

Depends on approach.... for some I don't use transition, just make sure that I am at the right ALT and speed....than "VECTOR" myself with small correction. Over the years I played with many different ways until became routine. 

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5 hours ago, skelsey said:

VNAV is a useful tool which can be a great aid to a safe and efficient flight but it is not infallible (in fact, anything but).

Ernie

Simon's above is spot on .... more so in the sim & perhaps even more so with some addons.

as far as the lnav turns being wide, shouldn't be an issue from my perspective, the examples you give have flyby waypoints not flyover, so again perhpas a glitch with the E175 (on the HILEY star, i'd use the RNAV approach as a guide as to what level to cross HENDN in V/S mode ....  on the CHPPR star, extend that downwind before a self vector for a 60o base leg intercept in HDG mode)

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Thanks all.  Looks like I'm going to have to do some hands on towards the end.

I've been avoiding it until I hit the glide slope because the cockpit management stuff is a bit overwhelming, but I guess it's time to buck up.

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Posted (edited)

Actually, I think there's another issue here that's not being accounted for. 

Both of these STARs are "Radar Required", and both feature the phrase "... expect radar vectors to final approach course."  You can't fly this type of STAR/approach combination flying nothing but published fixes.  That's not how they're designed to work IRL.  If you're not using some sort of live ATC, at some point you're going to have to play the part of both pilot and controller, figure out reasonable intercepts to the final approach course and self-vector.

Using the KATL example, in real life you would never proceed directly from YURII (the last fix shown on the STAR) to the IAF on the approach as you've attempted.  You'd be vectored (and would be given both heading and altitude info) sometime around YURII to set up a reasonable intercept angle and altitude.

Bottom line - without vectors, you're not flying the STAR as its published.

Scott

Edited by tttocs

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