747 FMC Questions

[adamv66 0]

Hey,Couple of questions regarding the FMC....I'm running the latest patch and the cost index range of values are 0-500 not 0-99 as mentioned in the manual. Is this correct? I'm guessing this is down to the "recalibrated cost index model" mentioned in the update??Also, I'm struggling with the offset path functionality......During cruise I try to set an offset path by going to the ROUTE page and entering something like 01L or 1L or 10R in the scratchpad then upselecting to the OFFSET LSK. But no matter what I seem to enter I always get an "INVALID OFFSET" message.. Any ideas??Many Thanks!Adam

[Guest capntom]

For simplicity sake, use a cost index of 100, the plane is easier to fly, limit excedence wise, at this cost index. At 200 and above, she will tend to overspeed on ocassion.Tom

[Guest brand_da_man]

Its not very realistic to just use cost index's up to 100, as i know that Qantas 747's use a cost index of 200. It makes it more enjoyable to fly (i find anyway) with the realworld cost index along with other information and that.Brandon

[jdk2 1]

>Also, I'm struggling with the offset path functionality......>During cruise I try to set an offset path by going to the>ROUTE page and entering something like 01L or 1L or 10R in the>scratchpad then upselecting to the OFFSET LSK. But no matter>what I seem to enter I always get an "INVALID OFFSET">message.. Any ideas??>>Many Thanks!>>AdamHi Adam,L or R precedes the distance(XX) when you input the desired offset: LXX or RXX .Jimhttp://www.precisionmanuals.com/images/forum/pmdg_pf.jpg

[adamv66 0]

Hi Jim,Tried that and still getting INVALID OFFSET... I'm at a loss... :-hmmmAdam

[emvaos 13]

Adam,You cannot create an offset of the active waypoint is :(a) Part of a SID(:( Part of a STAR© Part of an IAP(d) associated with a turn more than 120 degreesThe plane will fly any cost index with the same ease. Computers do not have feelings :) Captain Tom suggested 100 for your convenenience not the plane's.Best,Vangelis===================================== E. M. Vaos Precision Manuals Development Group www.precisionmanuals.com=====================================

[Guest capntom]

As to Cost Index.....I am flying for QANTAS this morning, PHNL-YSSY. I likely expect that the specified CI will be 100, as it usually is... The difference in cruise mach between 100 and 200 is 0.01 or less. Where there is a difference in the speeds that is very noticable is in climb and descent. The 200 CI gives a climb very close to the barber pole at the higher (freighter) weights that we fly at (zero fuel weight might be 285,000kg.). It is necessary to cut the FMC climb speed back to 350 kts/mach.xxx to avoid airspeed excedences if any turbulence is encountered at all. On descent the aircraft at heavy weights is slow to start down and then wants to overspeed to meet the path with a 200 CI. It's not supposed to, but does. I have had discusions with Boeing test pilots about this.For freighters flying at high weights, the plane is much more controllable and easy to manage with a 100 CI on climb and descent.With the pax birds, flying at the much lighter weights, no so much diffrence is noticed. Additionally schedules requiring gate slots and many other factors are not so easily changed. It may be that pax retention of the higher CI is not really a matter of choice at this point. There are a lot of factors, many non operational, that go into selection of CI. Tom