It did it again tonight, both engines derate setting #2, CI 66 lightly loaded from KSFO to KPHX. Planned altitude: FL370. At the end of climb, the plane was at FL400. This is embarrassing. It has been suggested "step climb" may be the culprit. Anyone??

Its definately auto step climb. I forgot what page its is in the FMC but you can turn it off

 

 

Anyone??

 

We're going to need more information than that.

 

The autopilot will not climb higher than the altitude set in the MCP (unless you're using that auto step feature).  If you're not setting it to your cleared altitude, you need to make that your practice.  If your initial altitude is 5000, you set it to 5000, even if you expect ATC to clear you before you get there.  Once you get cleared up to FL370, regardless of whatever you're expecting, altitude-wise, in the future, you set it to FL370.

 

Additionally, a step climb is used to keep the aircraft at an optimal altitude.  If you're flying a non-optimal altitude intentionally (there may be valid reasons behind this, ATC restrictions on routes being one of them), and you expect to remain there, your step size should be set to 0.  This is both for better fuel predictions, and to ensure that even if you do have the AUTO STEP feature on, that it won't do it when you're not paying attention.

 

In any case, it's doing it because you gave it permission somehow.

In any case, it's doing it because you gave it permission somehow.

Hi Kyle. I always set the MCP altitude for my initial clearance altitude from ATC. Must be that step climb feature. I wonder how I could have the plane step climb, but still go no higher than my planned cruise altitude. When ATC clears me to cruise, I dial that into the MCP and hit FLCH on the panel. As I get close to cruise, I flip on VNAV.

 

Seems like about half the time the plane goes higher, and what's worse, all the cruise altitudes in my FMC are altered to the NEW higher altitude, all without ME doing so! Now that's convenient! NOT!

 

 

I wonder how I could have the plane step climb, but still go no higher than my planned cruise altitude. When ATC clears me to cruise, I dial that into the MCP and hit FLCH on the panel. As I get close to cruise, I flip on VNAV.

 

To step climb, you don't need the AUTO STEP climb feature, just so you know.  Especially on a short flight like that.  First, it's not realistic (the extra feature).  It's just there for those who have long routes and want to walk away from the computer for hours on end.  For a step climb in the real world, you ask ATC, get approval, roll the higher altitude up in the window, and hit the center of the button to get the FMC to pick up on it (without having to do the extra work of reselecting the new cruise altitude in the FMC too).

 

Additionally, you can certainly use VNAV in the climb, too.  Unless there are climb restrictions, there's no true advantage to either in the climb.

 

 

 

Seems like about half the time the plane goes higher, and what's worse, all the cruise altitudes in my FMC are altered to the NEW higher altitude, all without ME doing so! Now that's convenient! NOT!

 

It can be convenient.  You just need to understand what the convenience is there for, and how it's used.

 

First - again - step climbs are there under the assumption that you're flying the optimal altitude for the given weight of the aircraft.  If you're at a lighter weight on a shorter route (less fuel weight), your optimal altitude is going to be very high.  Even if you file a low altitude, or set that as your cruise altitude on the PERF INIT page, the FMC interprets the step size being above zero as you telling it "you need to be closest to the OPT altitude using RVSM (or whatever STEP SIZE your set in there if you overrode it) altitudes."

 

So, if you tell it FL370, but the OPT ALT is FL400, and you gave it a step size of RVSM, it will show FL410 on the legs pages.  Why?  Even though you said the initial altitude was FL370, the very reason you use steps is to stay close to the OPT ALT.  As such, it will assume that you'll want to go to closest altitude (biasing higher) to the OPT ALT.  For this reason, you'll see the LEGS pages all displaying whatever the closest altitude is to that OPT ALT for the anticipated weight at that point.  If you're at a suboptimal altitude - regardless of it being near the beginning or the end of the flight - it's going to list the proper altitude for the optimal altitude.  That's why the FMC is doing that (and it's how the aircraft system is supposed to behave, because again, that's the whole point of the step: optimal altitude).

 

It would then follow that the AUTO STEP CLIMB feature would press you to those altitudes, because its very purpose is to:

1. Keep the plane at an optimal altitude (utilizing VNAV)
2. Let people not have to bother with following the optimal path manually (so they can walk off and not worry about it)

So, it's definitely convenient, but just like the convenience of an autopilot, you have to understand how it works to get it to give you that convenience.

 

To be honest, my recommendation would be to turn off the AUTO STEP CLIMB feature, and try to come to a little better of an understanding of VNAV itself.  In order to force it to avoid steps entirely, enter a step size of 0.  Additionally, if you're not going to use VNAV in the climb, you might as well use ALT HOLD when you're at your final FL, because VNAV is worthless if you're not going to fly the optimal cruise altitudes and use steps on your own.  Just select VNAV when you get closer to your T/D to let it handle the descent.

First - again - step climbs are there under the assumption that you're flying the optimal altitude for the given weight of the aircraft.  If you're at a lighter weight on a shorter route (less fuel weight), your optimal altitude is going to be very high.  Even if you file a low altitude, or set that as your cruise altitude on the PERF INIT page, the FMC interprets the step size being above zero as you telling it "you need to be closest to the OPT altitude using RVSM (or whatever STEP SIZE your set in there if you overrode it) altitudes."

 

So, if you tell it FL370, but the OPT ALT is FL400, and you gave it a step size of RVSM, it will show FL410 on the legs pages.  Why?  Even though you said the initial altitude was FL370, the very reason you use steps is to stay close to the OPT ALT.  As such, it will assume that you'll want to go to closest altitude (biasing higher) to the OPT ALT.  For this reason, you'll see the LEGS pages all displaying whatever the closest altitude is to that OPT ALT for the anticipated weight at that point.  If you're at a suboptimal altitude - regardless of it being near the beginning or the end of the flight - it's going to list the proper altitude for the optimal altitude.  That's why the FMC is doing that (and it's how the aircraft system is supposed to behave, because again, that's the whole point of the step: optimal altitude).

 

It would then follow that the AUTO STEP CLIMB feature would press you to those altitudes, because its very purpose is to:

Keep the plane at an optimal altitude (utilizing VNAV)

Let people not have to bother with following the optimal path manually (so they can walk off and not worry about it)

So, it's definitely convenient, but just like the convenience of an autopilot, you have to understand how it works to get it to give you that convenience.

 

To be honest, my recommendation would be to turn off the AUTO STEP CLIMB feature, and try to come to a little better of an understanding of VNAV itself.  In order to force it to avoid steps entirely, enter a step size of 0.  Additionally, if you're not going to use VNAV in the climb, you might as well use ALT HOLD when you're at your final FL, because VNAV is worthless if you're not going to fly the optimal cruise altitudes and use steps on your own.  Just select VNAV when you get closer to your T/D to let it handle the descent.

Thank you very much, Kyle. Your insightful and precise explanation is a Godsend. I totally appreciate the time and effort you put forth in writing it, and will implement your suggestions immediately.

 

I have one other issue, that revolves around getting the plane to slow down and descend properly. I had previously found with the NGX and somewhat with the new 777 that both planes are a bit tough to slow down at landing time. Even using the ILS approach, quite often the plane does not descend properly and I have to manually fly it to get it aligned with the purple vertical diamond on the ND. Pulling back on the throttles does NOT slow the plane as you would imagine it should, particularly at touchdown time, I oft times must deploy the spoilers to get the plane to stop floating above the runway.

 

I realize that slowing down while descending at the same time is a little much for a beast as heavy as the 777, of course I also know that if you have too much fuel on board that acerbates the problem. I use fuelplanner.com to plan my fuel loads, and have recently purchased PFPX and Topcat as well. I have to say that Topcat is annoying, it doesn't have a performance profile for the 777. Therefore it is useless to me. But I diverge.

 

I have attempted to enter a dead zone for my throttle quadrant (Hotas Warthog set) in Windows 7 control panel, devices and printers. I thus far have avoided using the Thrustmaster T.A.R.G.E.T. software to enter a deadzone for the throttle because it's just one more bit of software to pile atop my FSX experience and OOM's are a definite concern.

 

What I wish for is a way to gain greater control over the speed of the 777, especially at approach and landing time. If you have suggestions, I am open to them. I typically have to turn off A/T, A/P, and Flight Director and manually operate the throttles. I am specifically talking about problems coming in too fast with gear down and flaps maximum. Even with the airbrake/spoiler deployed at in-flight position, often I am still much too fast as I get near the threshold.

 

Clearly being 'too high' and 'too close' can play a role, but it isn't realistic to be 1000' altitude at KSFO and 5 miles out. So I know something is not quite right.

 

I hesitate to ask for further help after your wonderful post about step climb, but clearly your skills are considerably higher than mine, so if it isn't too much bother, a tip or two would be much appreciated.

 

Thank you, Kyle!

 

 

Thank you very much, Kyle. Your insightful and precise explanation is a Godsend. I totally appreciate the time and effort you put forth in writing it, and will implement your suggestions immediately.

 

Welcome!  Glad it helped!

 

 

 

I thus far have avoided using the Thrustmaster T.A.R.G.E.T. software to enter a deadzone for the throttle because it's just one more bit of software to pile atop my FSX experience and OOM's are a definite concern.

 

That software would be running outside of FSX.  OOMs associated with FSX are only for internal processes to FSX - loading the aircraft, loading scenery, loading textures.

 

 

 

What I wish for is a way to gain greater control over the speed of the 777, especially at approach and landing time. If you have suggestions, I am open to them. I typically have to turn off A/T, A/P, and Flight Director and manually operate the throttles. I am specifically talking about problems coming in too fast with gear down and flaps maximum. Even with the airbrake/spoiler deployed at in-flight position, often I am still much too fast as I get near the threshold.

 

Honestly sounds like your hardware throttle is interacting with the A/T.  Remember that the default hardware interaction allows you to override the throttles in HOLD/ARM mode.  Much of your descent is in one of those modes.  If your hardware throttle is anywhere above idle, the sim will use that throttle setting until the A/T switches to another mode later on in the descent.  This setting can be changed such that the A/T always overrides your hardware at any time it's on in the FMC options pages.

 

The settings are further explained in the intro manual.

Honestly sounds like your hardware throttle is interacting with the A/T.  Remember that the default hardware interaction allows you to override the throttles in HOLD/ARM mode.  Much of your descent is in one of those modes.  If your hardware throttle is anywhere above idle, the sim will use that throttle setting until the A/T switches to another mode later on in the descent.  This setting can be changed such that the A/T always overrides your hardware at any time it's on in the FMC options pages.

 

The settings are further explained in the intro manual.

 

Again, many thanks to you, Kyle!  I will read up more on the A/T modes in the manual.  Meanwhile, it sounds like my throttles need to be in full idle position once I have taken off and switched to A/P, until I switch to manual mode, yeah?

 

 

Meanwhile, it sounds like my throttles need to be in full idle position until I switch to manual mode, yeah?

 

I use this:

 

As necessary for taxi

For takeoff, set 55%, click TO/GA, match hardware to the rated thrust (because it drops to THR HOLD for a while during the takeoff roll)

After departure, leave it where it was (the A/T won't change to any modes where it would conflict) through cruise

Prior to T/D, set idle

Leave at idle (leaving A/T on through the landing, unless you prefer the control yourself)

 

...or set the override setting to always override your hardware throttles (which is the bit in the intro manuals).

 

 

use this:
 
As necessary for taxi
For takeoff, set 55%, click TO/GA, match hardware to the rated thrust (because it drops to THR HOLD for a while during the takeoff roll)
After departure, leave it where it was (the A/T won't change to any modes where it would conflict) through cruise
Prior to T/D, set idle
Leave at idle (leaving A/T on through the landing, unless you prefer the control yourself)
 
...or set the override setting to always override your hardware throttles (which is the bit in the intro manuals).

 

Yes, I do about as you do - except for pulling the throttles back to idle prior to Top of Descent.  I shall try that and see how I do.

 

Once again, many thanks, Kyle!

 

You're the best  :im Not Worthy:  :im Not Worthy:

 

 

Once again, many thanks, Kyle!

 

Welcome!  Let us know if there are any issues.

Welcome!  Let us know if there are any issues.

You're too kind. Thanks a million.