Altitude Problem

[Abdulrafeysiddiqui 0]

Hello! I have a problem on PMDG 747-400x that when I set cruising altitude in fmc and then in autopilot panel, For example FL320, the aircraft reaches to FL320 then it does not become stable on FL320 rather it goes 200 feet up and down continuously. Can anyone of you help me and another thing that is this real problem, I mean does this thing happens in real aircraft or it becomes stable when it reaches the assigned altitude?

[Nathan3219 113]

Hello! I have a problem on PMDG 747-400x that when I set cruising altitude in fmc and then in autopilot panel, For example FL320, the aircraft reaches to FL320 then it does not become stable on FL320 rather it goes 200 feet up and down continuously. Can anyone of you help me and another thing that is this real problem, I mean does this thing happens in real aircraft or it becomes stable when it reaches the assigned altitude?

 

This happened to me once before. I think it's speed compression, because it happened to me when I turned up time compression. Not a big deal really, just turn on the seatbelt sign and give the plane about 30 seconds to a minute to recover

 

As for your question about the real aircraft, no... the real 747-400 does not go up and down continuously when at cruise... it becomes stable.

[Abdulrafeysiddiqui 0]

I dont understand, what is speed compression?

I dont understand, what is speed compression?

[pete_auau 1,159]

I dont understand, what is speed compression?

I dont understand, what is speed compression?

Think he is referring  are  you using  time  accel at all during  flight or  are you just using  normal time

[Abdulrafeysiddiqui 0]

Think he is referring  are  you using  time  accel at all during  flight or  are you just using  normal time

 

Think he is referring  are  you using  time  accel at all during  flight or  are you just using  normal time

 

time acceleration is normal :rolleyes:  but it happens!!!! 

[Rickie Welsh 27]

Hello,  I am not an expert but I have been told that the FMC calculates the route distance, weight, fuel and determines a good altitude for the flight.  This happened to me a long time ago and when I looked at the legs page the altitude was at a higher level that the one I had entered i.e. I had 33,000ft and legs page showed 37.000ft.  I then changed alt. to 37000 and all was well.  Hope this helps.  Richard Welsh.