Hello,

 

I know this has to do with my real world weather application which is the Rex essentials plus overdrive.. but I don't remember having this issue before SP1. I have been flying the 300ER and the altitude jumps 200-300 feet every now and then, sometimes less, sometimes more. I think it is correcting the altitude for the pressure every time I enter a new area with a new baro setting. I have it set to STD as I am over transition altitde. Why would it still be correcting if I am in STD mode? I took out the weather application and everything was stable so I know it is a conflict with the weather program. Any ideas? The result is it messes up my time compression and it's really annoying.

 

Scott

Could it be your weather program creating turbulence ?

This is a flightsim feature that has always been with us - every aircraft I've ever flown has done this from time to time.

 

DJ

Because you have step climbs turned on in your PMDG.

Regardless of what Cruise altitude you give in your PERFORMANCE settings in FMC, aircraft will follow the altitude levels in the LEGS page.

 

To disable this go to your PMDG Setup in FMC and turn off AUTO STEP CLIMBS.

Could it be your weather program creating turbulence ?

I disabled the turbulence levels with the weather program so I know it's not that. 

 

Because you have step climbs turned on in your PMDG.

Regardless of what Cruise altitude you give in your PERFORMANCE settings in FMC, aircraft will follow the altitude levels in the LEGS page.

 

To disable this go to your PMDG Setup in FMC and turn off AUTO STEP CLIMBS.

I am not really sure how this applies? It's only a couple hundred feet jumps and it happens in between legs.. so I don't see how it would go to a new altitude multiple times between waypoints? It's not searching for a new altitude it just jumps sporadically. 

 

Scott

yes I have meet the same problem with 77W & ASN. And I am very sure climb and cruise are stabilizing before. Haven't try the 777-200LR SP1. 

QNH changing without smoothing probably.

 

If the QNH has a large change between weather stations, some weather engines will not "smooth" the transition, but rather, one second you will be flying where the real QNH is say, 1022mb, and the next second it will be 1014mb.

 

The aircraft will not have changed it's 'real above the surface' altitude, but the air pressure density (read: altimeter) will read differently. The aircraft will need to climb/descent (change it's height above the surface) to regain altitude (the barometric measure of altitude).

 

FSUIPC can help here by smoothing barometric changes (instead of being an instant change, the change will happen over several seconds - giving the aircraft a chance to smoothly climb).

I havn't seen any of this behaviour since I started using ActiveSky Next, although this may have been hidden by my pre-existing FSUICP settings from when I used to use different weather software.