PMDG 737 NGX Check alt TGT

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Nareg Haladjian

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Today 4:22 PM
Hi. I recently bought Radar Contact for FSX for more realistic flying. I cam upon my first problem today when I requested a lower altitude. I was at flight level 320 and requested flight level 320. I set the altitude in the MCP to 28000, and then set the altitude in the legs page to 280. I suddenly got a check alt TGT message and vnav disabled. It switched to altitude hold on the MCP and I can no longer enable vnav. Could someone help me on this? Thanks :)
 
Wrong procedure - you do not need to set the FL in the legs page. You can just select the FL280 on MCP and press Altitude intervention (ALT INT). VNAV will handle this just fine.

Jan
 
Jan Betlach said:
Wrong procedure - you do not need to set the FL in the legs page. You can just select the FL280 on MCP and press Altitude intervention (ALT INT). VNAV will handle this just fine.

Jan
Click to expand...

Ok thank you so much :)
 
Nareg Haladjian said:
Jan Betlach said:
Wrong procedure - you do not need to set the FL in the legs page. You can just select the FL280 on MCP and press Altitude intervention (ALT INT). VNAV will handle this just fine.

Jan
Click to expand...

Ok thank you so much :)
Click to expand...

You are very welcome :)
 
Hi additionaly , what ALT.interv. does is updating your cruise alt thats why FMC will perform step climb or descent .However when climbing out and you are ask to level off then climb again if the ddesire alt in fmc is set below to your cruise alt in CDU it will only resume climb . Always check your CDU for input for cruise alt when doing step cl. cruise alt will refer to your performance so it will change also mach regarding to your CI. So simply if you are in FL 280 and then you decide to make a step to 360 using vertical speed sure the plane will climb ,however will not update cruise alt in CDU so FMC will keep previsously calculated mach number for FL 280. same with descent . Additionaly to descent if in less then 50NM from TD the fmc will perform early descent . I am not sure exactly how fast ,but I think it is 1000 Fpm then if vnav path intercepted it will activate vnav path and try to stay on it . If more then 50NM it is only change of cruise alt ,however alway verifyied that cruise alt has been updated . Hope my broken English is clear enough . happy flying
 
Not much to add, but I believe the "check alt target" warning in the FMC in general refers to you updating FL to perform a climb when the FMC expects a descent for the next wayporint - or other way around.
For example if you are at 280 during or nead the descent, and next waypoint has a FL of 240 and you try to climb you get that warning. Otherwise you'd usually end up with "Des path unreachable" or something like that.
 
some days ago i experienced this error for the first time - i did the normal error-handling:
Step 1: check if there is an acknowledge-the-error-button
>>> Found: continue with Step 2
>>> Not Found: C'mon keep searching for the damn button - back to Step 1
Step 2: Press button to acklowledge error
Step 3: does this works?
>>> Yes: You are safe - get back lookin' out the window
>>> No: check Pilot Problem Solving Chart below - back to Step 1

pilot-problem-solving-flowchart.jpg
 
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