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felipeturbay

how to step climb

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hello guys,

 

can someone explain me how the step size works in pmdg 747? I have read the FMC manual but I still dont get the logic how it works. On the FMC I input in the ICAO = 2000; afterwards when I look the Vnav - cruise section sometimes I see a step size indicating a hight altitute. Will the FMC take me automatically to this indicated altitute or do I have to enter it manually in the Autopilot?44

 

thanks! 


felipe turbay

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The A/P should not change your FL automatically at all ! Very dangerous if it did.

 

I think you just select a new FL in the cruise page, then change the altitude on the MCP. Not sure if you need to press the VNAV button to get it to start its climb. I usually start a step climb in V/S mode anyway, then switch to VNAV.....smoother for the virtual passengers !

 

Peter


Peter Schluter

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Set the new altitude on the MCP, then change the CRZ FL in the FMC to the new step height. 


Dev Singh

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On the FMC I input in the ICAO = 2000; afterwards when I look the Vnav - cruise section sometimes I see a step size indicating a hight altitute.

 

First, you're confusing terms here:

STEP SIZE - ICAO means you're using the ICAO standard of 4000' altitude separation.

STEP SIZE - 2000 means that you are using 2000' altitude separation instead.

 

That 2000' is applicable in places like the United States where we use RVSM, where the aircraft is capable.  In the past, we had to separate aircraft by 2000' because of the less accurate altimeters.  Now, with better altimeters, that is reduced to 1000'.

 

That 4000' (ICAO) is there because - in a non-RVSM environment - if FL290 is eastbound, the next altitude available above it - FL310 - is westbound.  The next available altitude for eastbound travel would be FL330, and the differences between each available eastbound altitude is 4000'.

 

In an RVSM area, odd altitudes are eastbound and even altitudes are westbound.  In order to go from odd to odd, or even to even, you have to climb in 2000' increments.

 

drvsm.jpg

 

So, that's the background of why you're using either ICAO/4000, or 2000 in that box.

 

 

 

Will the FMC take me automatically to this indicated altitute or do I have to enter it manually in the Autopilot?

 

No.  Relying on a feature like that could get you in a lot of hot water.  Even though your flight plan may show that you'd like to climb at a certain point (often noted in plans as M###F###: M082F350), your clearance on your route is not implicit clearance that you will be able to climb at that point. So, if you weren't paying attention and the plane hit the step and automatically climbed up into the aircraft above it (or near it), you're going to get the book thrown at you.

 

Yes, the MD-11 is capable of doing it, but you're not going to find a pilot who is going to set it up to let do its climbing all automatically (by rolling the altitude selection up to the highest altitude, and letting the plane fly the vertical profile).

 

One of the best ways I've found to work step climbs is to roll the altitude selection up to the next altitude.  Look down at the FMC, and on the VNAV/CRZ page, click the LSK next to the STEP altitude.  This places the step altitude in the scratchpad, where you can then click the CRZ altitude's LSK to overwrite it.  Once the new altitude is in the CRZ spot, click EXEC and watch the automagic bring you up to the next altitude.


Kyle Rodgers

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Thanks Kyle, thats a nice piece of information!!

 

You're welcome!  It's always nice to know the reasoning behind what you're doing!


Kyle Rodgers

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Hi Kyle!

A step climb in the B744 can be achieved by just setting the new altitue on the MCP and pressing the knob. This will update the CRZ ALT in the CDU to the new value and initiate the climb without any other action, unless desired.

Cheers, Richard


Cheers, Richard

Intel Core i7-7700K @ 4.2 GHz, 16 GB memory, 1 TB SSD, GTX 1080 Ti, 28" 4K display

Win10-64, P3Dv5, PMDG 748 & 777, Milviz KA350i, ASP3D, vPilot, Navigraph, PFPX, ChasePlane, Orbx 

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A step climb in the B744 can be achieved by just setting the new altitue on the MCP and pressing the knob.

 

Hey Richard - you know, I always forget about that function.  That's a good point!  Now that I think about it, doesn't the FMC also pay attention to the altitude wheel?  As in, can't you roll it up to the next altitude and wait a second and the selected altitude will be in the scratch pad of the FMC?  I could be confusing my airplanes, however...

 

Thanks!


Kyle Rodgers

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Hey Richard - you know, I always forget about that function.  That's a good point!  Now that I think about it, doesn't the FMC also pay attention to the altitude wheel?  As in, can't you roll it up to the next altitude and wait a second and the selected altitude will be in the scratch pad of the FMC?  I could be confusing my airplanes, however...

 

Thanks!

 

VNAV ALT/SPEED intervention I think it's called.


Dev Singh

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VNAV ALT/SPEED intervention I think it's called.

 

Sounds about right.  I haven't flown the poor bird in such a long time, so my memory is a little shaky.


Kyle Rodgers

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Dev - You are exactly right.

 

Kyle - You are thinking of a different ship, I feel.

 

Cheers, Richard


Cheers, Richard

Intel Core i7-7700K @ 4.2 GHz, 16 GB memory, 1 TB SSD, GTX 1080 Ti, 28" 4K display

Win10-64, P3Dv5, PMDG 748 & 777, Milviz KA350i, ASP3D, vPilot, Navigraph, PFPX, ChasePlane, Orbx 

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Right on Dev -

 

I use step climbs a lot because I really like planning and flying polar routes and the hefty fuel loads require them. I set the new altitude in the MCP and press Altitude Intervention and the CDU updates as you say. Step climbs save alot of fuel (based on winds, speed and load) and it is fun to try and beat the planners back at route control. It also keeps you awake and at the controls instead of sneaking off to to the kitchen for a snack.


Rick Bertz

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Right on Dev -

 

I use step climbs a lot because I really like planning and flying polar routes and the hefty fuel loads require them. I set the new altitude in the MCP and press Altitude Intervention and the CDU updates as you say. Step climbs save alot of fuel (based on winds, speed and load) and it is fun to try and beat the planners back at route control. It also keeps you awake and at the controls instead of sneaking off to to the kitchen for a snack.

 

I think with polar routes you have plenty of time for snacks at kitchen LOL 


Joona Väisänen

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