Need some help

[dolin 0]

Hi to everybody,i would like to ask you informations about an FMC message, and a minor issue ( I'm using the PMDG 747 for FSX Acceleration)1- "UNABLE NEXT ALT" this message pops up sometimes during initial FMS preparation prior to the flight, especially when I am departing from Heathrow. I'm pretty sure this message is about an error with the SID altitude restrictions , but I don't know how to fix this (well, even with this error I'm able to take of and fly the SID in VNAV without problems, it's just a "nice to know")2- I always use the Queen with FS2Crew (virtual First Officer and Cabin Crew) and Radar Contact (ATC replacement for the FSX default one); when I get to the Top of Descent, Radar Contact instructs me to descent well before that point, this happens both in short (yes, i use the 747 in short routes, like Taipei/Hong Kong) and long flights. Ok, I can understand that in short flights ATC may tell me to descent earlier because of traffic or other reasons but in long haul flights, like Sydney/Los Angeles, there is time to plan everything and perform FS2Crew's checklists and I would like to decide myself when to descent, according to FMC informations (as real-world pilots do i guess, just see the ITVV Virgin Atlantic 744 video).Does anyone know about this and can help?Are there any ways to fix this?PS: this issue may regard more Radar Contact than PMDG, but Idon't really know where to startThanks in advanceGiulio Dondi from Italy

[downscc 1,327]

Ignore the advisory message. Once you are airborne and climbing you shouldn't have a problem with the Heathrow SID constraints, even very heavy. I've tried Radar Contact but you are right, it's not quite right for me. Real world TODs usually are pilot discretion as long as you get down to the constraint by the time you reach it. Sometimes the constraint is the fact the current controller needs to hand you off to another sector but usually they don't care how long you stay high. There are lots of RC fans here and next door in that forum that probably have work arounds that they use.

[dolin 0]

Ok, i'll ask themThanks anyway!