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Big_Les

Step climb

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I've been trying to get step to work without any success, the FMC always says "unable" at step point. Heres what I do: 1. At cruse level FL340 I set MCP to FL3602. Look at optimum cruise level in FMC and check it's above FL 3603. FMC cruise page set step to FL3604. Execute change I'm expecting to see an auto calculated step point and then a step climb at the point, all I get is "unable" at the step point on the FMC. Any ideas? I think I'm doing this as per the manual, but if I'm honest, I haven't ingested the whole 2,000 pages of it yet......


"Military Intelligence is a contradiction in terms"

Paul Yates

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I've been trying to get step to work without any success, the FMC always says "unable" at step point. Heres what I do: 1. At cruse level FL340 I set MCP to FL3602. Look at optimum cruise level in FMC and check it's above FL 3603. FMC cruise page set step to FL3604. Execute change I'm expecting to see an auto calculated step point and then a step climb at the point, all I get is "unable" at the step point on the FMC. Any ideas? I think I'm doing this as per the manual, but if I'm honest, I haven't ingested the whole 2,000 pages of it yet......
Many reasons : Cruise setting on MCP, Performance (fuel weight, payload), pressurization.

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Well, i think that MAX FL is considring the performance and weight, isn't it?What do you mean by preaaurization? Should i set the new FL in the cabin alt in order to get the FMC to calc SC point?


Sagi Yanay, VATIL

NGX Driver

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I've been trying to get step to work without any success, the FMC always says "unable" at step point. Heres what I do: 1. At cruse level FL340 I set MCP to FL3602. Look at optimum cruise level in FMC and check it's above FL 3603. FMC cruise page set step to FL3604. Execute change I'm expecting to see an auto calculated step point and then a step climb at the point, all I get is "unable" at the step point on the FMC. Any ideas? I think I'm doing this as per the manual, but if I'm honest, I haven't ingested the whole 2,000 pages of it yet......
I submitted a ticket regarding a bug in the FMC step climb behavior just yesterday, Ryan put it on the bugs tracking list (the internal one, not the one pinned in the forums). Robert

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"Unable" doesn't mean that the plane cannot climb, but that there is no fuel savings from performing the step climb. Consequently the FMC is "unable" to compute a point where you should step climb. If you look a bit further down on the CDU, you should see that there is either a savings of 0% or a penalty computed for the step climb.

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Or you should change the FL on the INIT PERF page to the higher altitude. (?)


 

Regards,

Martin Martinov / VATSIM 1207931

 

fs2crew777.jpg

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Or you should change the FL on the INIT PERF page to the higher altitude. (?)
If you want to change your cruise altitude, change it on the CRZ page, top left corner.

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Oh man, so many bad habits from the "realistic" recent 737s ...


 

Regards,

Martin Martinov / VATSIM 1207931

 

fs2crew777.jpg

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Got it to work fine after setting up on the ground today, step and step point was calculated correctly and stepped after hitting altitude intervention on the mcp.


"Military Intelligence is a contradiction in terms"

Paul Yates

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So Big_Les,What was missing?
Not sure. The only differences were:No windSetup step on the ground not in the air
Many reasons : Cruise setting on MCP, Performance (fuel weight, payload), pressurization.
As I said in my original post.... MCP cruise is increased to FL360, performance is covered by the optimal flight level suggested in FMC and pressurization??? not sure what relevance that has unless you're trying to go above max flight level (which I'm not) so....none of the above.

"Military Intelligence is a contradiction in terms"

Paul Yates

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This is a simple process. 1) determine if you can attain the new cruise altiude by going to CRZ page and cecking the OPTIMUM crz level. Some companies have different criteria for this. In THIS example lets just say the OPTIMUM sys 360. 2) dial 360 on the mcp altitude window3) on cruise page enter 360 in top left LSK and EXECute it.4) plane should start climbing. THATS IT. 5) the pressurization panel is reset to 360. It has NOTHING to do with step climb other than adjusting the differential/ cabin altitude

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Jack,The climb itself is easy - like you explaind. The question is, foe example, I'm cruzing at FL340. The FMC advise OPT FL373 / MAX 378. When typing FL360 for the step climb, the STEP POINT is UNABLE.


Sagi Yanay, VATIL

NGX Driver

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UNABLE usually means that the step point is within 200 (if I remember correctly could be 100) miles from the ToD or no SAVINGS but PENALTIES. FYI : It calculates a "parallel" flightplan with the step point. You can also downselect it and put in 1LSK. FYI : Continuing from above post... In CRZ phase you can also roll your MCP ALT to 360 (say) and press ALT INTV. PS. Warning when you ask for a STEP above the MAX ALT it will issue a warning like MAX ALT FLXXX but will calculate


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E M V

Precision Manuals Development Group

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