Crz but i am on descent?

[clayton4115 56]

hi allas you can see in this pic, i am on descent into sydney but its telling my in still in CRZ?help!http://forums.avsim.net/user_files/117317.jpg

[Max Kraus 339]

Yes i've noticed that too. It is strange, since you're dead on the VNAV descent path and everything else there is in descent mode.

[shortspecialbus 13]

If you're referring to the N1 limits in the rightmost display, there are no specific N1 limits for Descent, so it stays in Cruise unless you do a go-around or something.At least that is my understanding, and it's probably simplified as to what actually happens.-stefan

[kmanning 12]

Hi Clayton,The airplane looks like it's doing what it's suppose to do. Are you referring to the CRZ displayed above the N1? You'll noticed that the N1 does not drop to 20.4 percent as it does at sea level, even though the engines are at idle. You're at 20,500ft and the air is less dense and the temperature is much lower than at sea level. The N1 is dependent on the air density and temperature. Ken.

[clayton4115 56]

hi Ken,thanks for the information, so what it states, just above N1 "CRZ" is correct and thats how it is in real life?

[Mats_J 2]

Hi Clayton,I'm not Ken but I will answer anyway! ;-)Yes the CRZ annunciation you see on the Upper Display Unit just above N1 is how it is in real life too.The N1 mode is not the same as the flight phase.Cheers,

[clayton4115 56]

so if i had throttled back to idle would that have changed to DES?

[Mats_J 2]

No! ;-) There is nothing called DES when it comes to the A/T N1 modes. This only depicts the max limiting thrust for different stages. The N1 mode you/or the FMC selects will change the green reference B1 bug on your N1 gauge on the engine display.There's five N1 max limit thrust modes (and some sub modes):TO(-1, -2) for take off thrust (derate 1 and 2)GA for go aroundCLB(-1, -2) for climb thrust (derate 1 and 2)CON for max continuos thrust and finally CRZ for max thrust in cruizeAs you are throtteling down on descent there's no need for a max limit descent mode. What values would that mode show?In the FMC you have three stages of flight CLB, CRZ and DES. This applies to the path calculations done by the FMC for predictions and VNAV calculations. This is a totally different animal than the N1 modes above. In fact you can manually select a CLB N1 mode for the A/T while in VNAV DES phase. This will only tell the A/T what max thrust it is allowed to throttle up to if it gets the demand for thrust i.e. speed dropping. But as you are in the descent phase you are not likely to ever get near to those limits.Hope it makes sense,

[clayton4115 56]

hi Mats thanks, that helps alot.