auto step climb

[AzN1337c0d3r 3]

This feature is mentioned in the tutorial and introduction, but I can't seem to find a definite answer on how it works. Anyone know?

[Olympic260 415]

have you activate the option?

 

From FMC FS Actions-> Auto Step climbs. Default is to NO

 

 

If yes then simply dial your initial cruise altitude in MCP if a step climb is programmed or calculated when aircraft reaches s/c point the mcp altitude will automatically change to the new altitude and plane will climb

[AzN1337c0d3r 3]

have you activate the option?

 

From FMC FS Actions-> Auto Step climbs. Default is to NO

 

 

If yes then simply dial your initial cruise altitude in MCP if a step climb is programmed or calculated when aircraft reaches s/c point the mcp altitude will automatically change to the new altitude and plane will climb

I did exactly as you said. When I approach the S/C point, the FMC seems to get stuck at 1 nm to go and never actually steps the aircraft. 

[Olympic260 415]

Stramge. It was working on me last time I checked. I will try to recheck in mean time better open a support request with PMDG.

[ahuimanu 50]

I was about to start a new topic on this, but I'll add to this one.

 

I would like to divine the exact steps as it is not clear enough from the PMDG-777-Introduction.pdf document.  Also some step climb features are discussed in the PMDG-777-FCOMv2.pdf document with respect to the FMC, but there is no "auto step climb" in the actual aircraft.  From 11.42.22 of FCOM2, I can assume that the S suffix on an altitude restriction, or a calculated step climb, are the only things addressed in the actual aircraft.

 

As for the feature in the sim, it seems that I must:

 

1) Enable "Auto Step Climbs" in the Auto Cruise menu in the FS Actions Menu

2) Enter in a route where step climbs are calculated (or where an altitude restriction for a waypoint has an "S" suffix)

3) Enter the initial cruise altitude in the Mode Control Panel

 

Is it correct to assume that this combo will be the ticket?

 

For my last few flights it hasn't worked, but I think I'm still in MD-11 mode where you put the final cruise altitude (the highest you'll step climb to) in the MCP.

 

I'd be interested to see how it is supposed to work.

[hopskip 253]

That's how it worked for me.

 

Forgot to turn it off once and accidently started a step climb on vatsim in an active ATC area without clearance. The mad rush to stop the climb from FL357 and head back down to FL350 was interesting

[Paul_Smith 92]

I was about to start a new topic on this, but I'll add to this one.

 

I would like to divine the exact steps as it is not clear enough from the PMDG-777-Introduction.pdf document.  Also some step climb features are discussed in the PMDG-777-FCOMv2.pdf document with respect to the FMC, but there is no "auto step climb" in the actual aircraft.  From 11.42.22 of FCOM2, I can assume that the S suffix on an altitude restriction, or a calculated step climb, are the only things addressed in the actual aircraft.

 

As for the feature in the sim, it seems that I must:

 

1) Enable "Auto Step Climbs" in the Auto Cruise menu in the FS Actions Menu

2) Enter in a route where step climbs are calculated (or where an altitude restriction for a waypoint has an "S" suffix)

3) Enter the initial cruise altitude in the Mode Control Panel

 

Is it correct to assume that this combo will be the ticket?

 

For my last few flights it hasn't worked, but I think I'm still in MD-11 mode where you put the final cruise altitude (the highest you'll step climb to) in the MCP.

 

I'd be interested to see how it is supposed to work.

 

Specifing the 'S' on the altitude is simply a way of marking the route to indicate that you woud like to do a step climb at this waypoint, even if it is not the optimum place. It has nothing to do with auto step climb.

 

Auto step climb, if enabled, will allow the FMC to go ahead and do a step climb if all the required conditions are met. If it is disabled, then the PIC must initiate the step climb manually.

 

(Just re-read your post, one of the required conditions for a step climb is that the altitude on the MCP must at at or above your target altitude. Setting it to initial cruise will prevent auto step climbs.) 

[Airbusman330 300]

It seems like the plane performs the step climbs early, I was watching the cue on the NAV display and about 40 miles out the plane started the climb.

[ZKOKQ 986]

etting it to initial cruise will prevent auto step climbs

Not sure if I mis understood you here Paul, but at the moment, I am flying from OMDB to ESSA, I have FL350 set in the MCP, and just as I was reading your post, it is now step climbing to FL380. I had FL350 set in the MCP, but that has automatically changed to FL380. I have not touched the Altitude selector at all since climb out from Dubai.

[SAS263 1]

Agree with Badfinger. I set my Alt to the initial cruise FL and don´t touch it. Come back to the computer later on and the plane/FMC/hidden wizard has done the step climb all by it self, including setting the new cruise FL in the MCP.

[pcubine 143]

I believe it takes a leap of faith to assume the plane is going climb higher than what is in the MCP altitude window. Since the beginning of time we have been told that the plane will not climb above or descend below what is in the MCP window. Even though the MD-11 will do auto step climbs it will never go higher than what is in altitude window. None of this applies in the case of the 777. Through the magic of coding it does away with that inviolate principle and automatically changes the MCP window altitude to whatever altitude the plane is going to climb to.

 

The first flight I did that involved step climbs was KATL-FAOR with four climbs from FL300 to FL380. So I enabled auto step climb in the FMC, dialed 30000 in the altitude window and thought there ain't no way this mother is going above FL300 but it did. Prior to descending for FAOR the FMC showed waypoints at FL380, the plane was at FL380 and the MCP window showed 38000. It works.

 

Michael Cubine

[Lseatflyr 0]

Hey Guys-

 

Has anyone noticed any issues with Auto Step Climb and pilot-input step climbs (i.e. FL340S)?  I've had success with Auto Step Climb using FMC-determined step climb points.  However, when I set the step climb 0 and manually enter my step climbs on the legs page per the flight plan, Auto Step Climb seems to blast right through them and maintain the current altitude.  

 

Obviously, it goes without saying that I profusely apologize for missing anything in the documentation that covers this.  

 

-Tony Fiore

[SAS263 1]

Obviously I have no idea how the thing is programmed, but to me it makes sense that a setting of step climb 0 in the FMC (perf init?) overrides any auto step climb features, even when you manually enter a FL340S point. I´d guess that the auto step feature only works when the FMC calculates step climbs and you have programmed it to not calculate any, hence no auto step climb. Try doing the same thing but with RVSM/whatever instead of zero. Blank/delete the calculated step points so that the flight plan only have your manual step climb points.

 

It seems a bit conflicting in telling the FMC to not calculate any step climbs and at the same time enter a pilot entered step climb point?

[Lseatflyr 0]

The purpose of doing it this way is to basically give priority over the flightplanning engine's determination of when to climb.  The flightplan can optimize using a bigger picture of the weather conditions along the route as opposed to the FMC which optimizes based on current conditions the aircraft is experiencing.  

 

I'll play around some more with specifying my own step climbs on the legs page using /###S and different conditions of FMC-determined climbs (RVSM/2000/etc).  I believe the priority is given to whichever step climb comes first - the FMC-determined step or the pilot-input step.

 

Thanks for your thoughts Tord; your reply is appreciated!

 

-Tony Fiore

[SAS263 1]

Tony, I dug out my copy of Bulfers FMC User´s Guide (which I thoroughly recommend) and flipped through it. There is a lot of info regarding the FMC fuel calculations and it´s been a while since I looked at it. I think that you´re idea of replacing the FMC calculated step points with those from the flight plan is correct in order the get an accurate fuel plan for the flight. Note that winds are very important to enter, but I think that´s not surprising. What may be surprising is that no winds in the perf init page or RTE DATA pages means that the FMC calculates with zero winds along the route. It actually uses a mix of the current measured winds which are used to 100% near the current location, but further along the route it mixes in the entered forecast winds and at a certain point those are used to 100%. Having zero winds along the route obviously gives bad calculations.

 

As I said the guide is a pretty hefty document. I can´t find any info on wether one should zero out the Step Size when using manually entered steps. My GUESS is that one should leave it at say RVSM and enter the steps manually. This would mean that legs where a certain FL is required (NAT) locks the calculations/fuel predictions to that, but other legs can be calculated on the fly by the FMC, letting it use the current wind data which should be better then the forecast used in the flight plan. Live values should have preference over forecast values when possible. Hope my theory makes sense

 

Some other hints as to why Step Size should be entered (needs confirmation on how it works in the sim/IRL): On the cruise page, Step To is blank if Step Size is zero.

 

"If a specified step point is made on a LEGS page, 1R displays the flight plan STEP TO altitude corresponding to the specified step altitude on the next lateral flight plan leg on the LEGS page which has a step to altitude." (overrides calculated step points?).

 

There is an example in the book where the FMC calculates a step point at a point in the flight plan. By entering a specified step point further along the route, after the calculated point, the FMC will calculate fuel based on a step climb there, not the previously calculated one.

 

Oh, VNAV does not automatically perform a step climb when the specified step point is reached.

 

Again, lots of info and I have no idea how this is implemented in the PMDG bird. I hope I haven´t confused matters too much, and in the end we´ll have to try it out and see what happens. To summerize, my view is that a step size should be entered. Manually entered step points will override calculated ones. No clue how the auto step feature manages things, but it should use the step climbs in the LEGS page, regardless of them being calculated or entered manually.