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daniel.burke01

Slowing down your aircraft (using charts!)

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I just wanted to put out there the benefits of using charts when flying! I've been reading topics on how to slow down the -800 and using less of a descent profile and so on, but the benefits of vertical planning that arrival charts provide are a great tool in getting your aircraft to a manageable speed for landing. A lot of STARS provide vertical planning that asks you to expect a specific altitude at specific points and reference those altitudes to south or north, east or west landings. Many times these vertical crossings are NOT programmed into the stars from navigraph and looking at the arrival on the chart will give you these plannings. Take the BAIRN2 arrival at KMCO. The arrival I download from navigraph does not provide any vertical restrictions prior to final approach. My FMC will give me an esitmated crossing at BAIRN of about 13,000 to 14,000 ft depending on my cruise. However if I look at the actual arrival chart I see that at BAIRN it asks me to vertically expect to be at 8000FT for north arrival and 11000FT for a south arrival. This is a difference of almost 6,000ft to 2,000ft from what the FMC is estimating for my approach. By using the correct altitude restrictions this 6,0000 is made up well in advance by an earlier T/D and my trip from BAIRN to final is a smooth descent with control over my speed. I am not playing a game of catch up by having to nose up to slow down then set flaps then nose down to regain my vertical profile to keep me on path with Idle and speed breaks. If you haven't looked at charts before, I HIGHLY suggest it. The more you learn the more you'll discover how small things make SUCH a difference and the more fun it becomes! Just a tip for the day! Happy Flights!

 

~DAN BURKE~

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Crossing restrictions are there to help ATC not pilots. The FMC will give you a T/D that allows the most efficient approach; if you're still arriving too fast/high on final, you're doing something wrong.


Jordan Forrest

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Crossing restrictions are there to help ATC not pilots. The FMC will give you a T/D that allows the most efficient approach; if you're still arriving too fast/high on final, you're doing something wrong.

 

No, a heavy -800 is just really hard to slow down. And really hard to descend at a good rate when at 250kts or below.

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No, a heavy -800 is just really hard to slow down. And really hard to descend at a good rate when at 250kts or below.

 

 

I didn't say otherwise. However my point remains; if you're having to trick the plane into calculating an early decent point you're doing something wrong.


Jordan Forrest

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"Crossing restrictions are there to help ATC not pilots."

 

Well, it is actually a big deal. You have to follow all those restrictions. When we build and file routes at work we check and edit profiles if required especially into EWR or IAH. If you screw up profile and file it not like it published you may want to expect guests from FAA, because ATC sends out angry letters if we do not follow the procedures. The filed route and profiled is shown in the flight plan and crew has to load filed profile in FMS. I fly pretty often in cockpit, I see they load profile. Even if it last minute RWY change they still try to adjust profile unless ATC instruct otherwise. So you were right, it is for ATC but ATC want you to be filed and fly published profiles.

 

See you.


Edward

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Sorry Jordan I do not understand the logic, how are you tricking the system when you are only inputting a possible ATC requirement as quoted on a valid star plate to give you an adjusted TOD with now updated information. Absolutly no difference at all as the headwind/tailwind adjustment within the arrival forecast, maybe you do not utilise either.


Dave Baggs.

EGLL.

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It doesn't matter if you fly the whole journey at 3000 ft if you expect to steam in 10 miles from final at 340 kts.

 

After reading many reports of "it's hard to slow down" I tried several approaches that people talk about being difficult, and I have never had an issue slowing down for final.

 

The words we are missing to describe this problem are "pilot error" and "poor energy management". Maybe you can take some inspiration from this guy: [media=]

[/media]

 

The jet isn't at fault - it is the way it is being flown that is. It seems too many are expecting the FMC to replace thinking - it won't happen. If you stop flying the aircraft and get behind it, from what I keep reading here, you will probably never catch it up again until you're parked at the gate.

 

There is a reason for the saying "never let the jet fly where your brain hasn't been 5 minutes earlier".

 

Best regards,

Robin.

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Sorry Jordan I do not understand the logic, how are you tricking the system when you are only inputting a possible ATC requirement as quoted on a valid star plate to give you an adjusted TOD with now updated information. Absolutly no difference at all as the headwind/tailwind adjustment within the arrival forecast, maybe you do not utilise either.

"Crossing restrictions are there to help ATC not pilots."

 

Well, it is actually a big deal. You have to follow all those restrictions. When we build and file routes at work we check and edit profiles if required especially into EWR or IAH. If you screw up profile and file it not like it published you may want to expect guests from FAA, because ATC sends out angry letters if we do not follow the procedures. The filed route and profiled is shown in the flight plan and crew has to load filed profile in FMS. I fly pretty often in cockpit, I see they load profile. Even if it last minute RWY change they still try to adjust profile unless ATC instruct otherwise. So you were right, it is for ATC but ATC want you to be filed and fly published profiles.

 

See you.

 

The problem: Some find it hard to slow down/go down in the -800 using the calculated T/D.

 

T/D point is calculated so that with all things being equal you'll arrive at the E/D setup for landing. That's the whole point! If you still can't get the -800 to slow/go down using that original T/D, only by adding a restriction to cause an earlier T/D point, then you're doing something wrong.

 

As 3-2-1 Now said, it's all energy management; ATC is irrelevant.


Jordan Forrest

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I can see where Dan is coming from with his post and he raises a very good point about planning. Planning is definitely one of the elements of a successful flight.

 

For all, keep in mind though, that a VNAV PTH descent, which is basically an idle thrust lever descent, and works best if where the descent path is likely to remain free of ATC interference. So, any well laid plans for your TOD, descent planning may go out the window!

 

Here are a couple of real world examples where ATC interfere with a planned VNAV PTH descent screws up your best laid plans.

The first is, you get to the TOD and start a VNAV PTH descent. Everything is going smoothly until ATC tell you to maintain FLXXX for traffic. One minute later, ATC tell you to continue your descent. The airplane is now above the "planned" VNAV PTH. Good luck getting back to your original VNAV PTH! Now you have to either pitch over and increase your speed to increase the descent rate or use the speed brake or a combination of both. Or give in an tell ATC your not going to make that altitude contraint ahead so give me something I can work with!

The second scenario is instead of ATC stopping your descent; instead they tell you to reduce your airspeed. Now, the airplane will gradually go above the planned VNAV PTH descent. Again, getting back on the original VNAV PTH may not be possible!

 

 

ATC is very relevant, yes indeed!


John Floyd

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John, ATC IS irrelevant to our discussion.

 

In reference to our discussion, I will have just one recommendation - Use DESCENT FORECAST page! It is there for a reason. Airplane can not know how will the wind be halfway down - tell it, and it will move TOD as appropriate. It does not know what is the air pressure at destination, and how is ISA deviation throughout descent - tell it. Very importantly - tell it if you are expecting to use anti-ice, it does significantly increase residual thrust.

 

Also check that your thrust levers really are at idle, and nut just a bit above.


--Peter Fabian 
RTFM.jpg

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John, ATC IS irrelevant to our discussion

 

Peter, I disagree with you of course. In the real world, ATC affects descent "energy management" on every flight. Many forum members fly their SIM without the added realism of ATC interference, so it can be a bit unrealistic.


John Floyd

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Hi.

Where I work we give the RNAV STAR very early. Often 10-15 after departure so the pilots can plan their descent early on. When they finally get handed over to me in the tower I usually clear them for approach via the STAR on first contact. A few things to add is that many times we don't have that much traffic in our TMA that we need to alter their flight path and our RNAV STAR's lead them all the way to the FAF (Final approach fix) for the active runway.

Saying ATC affects EVERY flight is not true. All depends on the traffic load.

So I agree with Peter. If you tell the plane all it needs to know (Rwy, STAR, weather) you should establish on final with correct speed with only idle thrust throughout the descent. As long as ATC don't put in any restrictions as mentioned earlier.


Regards

Stefan Hillblom

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"Crossing restrictions are there to help ATC not pilots"


Jim Driscoll


 

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The charted restrictions and expected crossing altitudes are there for a reason, to provide ease of traffic flow, for safety and so on...

 

It sounds like those with difficulties staying on the calculated descent profile are not taking the prevailing winds into account. If you use real weather, be it FS internal or something Active Sky or REX, the chances are you are going to have winds mucking up your descent profile.

 

It is particularly bad with a tail wind, as you will either overspeed to stay on profile, or end up too high on final. The least you could do is use your 3rd party weather addon to give you an average wind report for the journey, failing that you could enter the wind speeds amnd directions into the forecast page, which will give the FMC the necessary information to recalculate the descent profile more accurately. Every time I found myself too fast and/or too high on final approach, it was because of a high tail wind component on the descent...

 

Just a thought... you use a high end addon like the NGX, you will need to feed it with the respective data so that it can do its job... otherwise, you will find it more than a handful to operate...

 

A


Andrew Entwistle

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Peter, I disagree with you of course. In the real world, ATC affects descent "energy management" on every flight. Many forum members fly their SIM without the added realism of ATC interference, so it can be a bit unrealistic.

 

You don't agree only because you don't understand what's being said.


Jordan Forrest

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