fmc errors

[hyperdallas 0]

I keep getting unable next altitude, whats wrong ? :(

[wunderlicht 0]

1) The next altitude is too close to either descent / climb to in the amount of distance you have to do so 2) The altitude requested is above the max rated altitude for the weight of the aircraft and temp outside.

[hyperdallas 0]

ok thanks also another question cost index? whats that is 450 good number?

[wunderlicht 0]

hahaha... NO! Use something between 20 and 80. The higher the num ber the faster you want to go and more fuel you are willing to burn. If this is too high, it will take you forever to finally get to cruise. This is because the plane will constantly try and match the speed requirement and disregard actual climb performance, as it should with high numbers. As the plane gets into higher thinner air the maximum Indicated Air Speed (IAS) allowable decreases. If the number is too high, with something, like say 450... you may run into a point where you stop climbing and the autopilot gets confused as it can't reach the speed it want to because its above the allowable IAS. In some extreme cases even descending to keep speed up. This is not good.

[hyperdallas 0]

hahaha... NO! Use something between 20 and 80. The higher the num ber the faster you want to go and more fuel you are willing to burn. If this is too high, it will take you forever to finally get to cruise.

lol k =) also see the pic, when do i start to lower my alt in mpc? once i go over ave i set 14k in mpc?

[wunderlicht 0]

Yes, before you hit the TOD point. (Sorry, again more to say...) Look to you Cruise Performance page for ETA and distance (to the ToD). I usually wait until 50-80 nm out before changing the MCP altitude. This is during the descent / approach brief. Be careful though... if you hit extreme turbulence or bump the control disconnecting the autopilot it wont remember to stay in cruise alt and you'll have to rush to reset the MCP for cruise altitude. Sorry about above post, I always have more to say after I say it.

[hyperdallas 0]

thanks wunderlicht,u* dont happen to have msn or skype so i could ask u some more questions rather than making spam post?

[wunderlicht 0]

Sorry, I'm actually away from home on business in Mexico... yerning to get back to my PC in 4 weeks! Just PM me and I'll try to answer any questions for you.

[Kosta 122]

From the manual:COST INDEXThe cost index is used to calculate ECON climb and cruise speeds. The value reflects the relative impacts on overall trip cost of fuel cost as compared to other direct hourly operating costs.Enter the cost index for ECON calculations.Entry is required to enable use of VNAV mode.Valid entries are 0 to 500. 0 causes the ECON speed to be MAX RANGE; 500 results in a minimum time flight.Entry of a company route on RTE page causes any company stored value of cost index to be automatically displayed. A manual entry has priority.Tutorial:Enter 25 and line select it into the COST INDEX field at LSK 5L.Cost Index is a measure of how much the FMC values fueleconomy vs. the overall speed of the flight. Lower values correlatewith lower operating cost at the expense of slower airspeeds andvice versa. Cost Index is a very powerful parameter in the FMC andit affects everything from climb, cruise and descent airspeeds to themaximum attainable altitude for the route. The valid range is 0 to500. And to my knowledge you can change it to see what's an optimal value to you. Airlines have CIs specified for to balance the fuel burn and speed. For instance, BA runs on their european flight with CI 28 (according to some websites).

[hyperdallas 0]

Sorry, I'm actually away from home on business in Mexico... yerning to get back to my PC in 4 weeks! Just PM me and I'll try to answer any questions for you.

sent u a pm

[VARIG 0]

There's no right number for Cost Index. Anyway, the 737 family has a range from 0 to 199 (sorry, that range was valid to Classic Family -3/-4/-5). BBJs have 0 to 399 the same range of NG, from 0 to 499. For example, in Brazil we have a low cost called GOL, that uses from 8 to 12. TAM uses 12 to 15... Varig used to use 20 - 50 and so on... Ryanair must use ZERO! hahahaha

[Kosta 122]

Ryanair must use ZERO! hahahaha

"We get you there slowly, but we get you there!"

[hyperdallas 0]

btw how do i enable autolanding feature :(? i am 25nm out and dont want to land my self :(

[wunderlicht 0]

Yes, most airlines are between 20-80 CI... Air New Zealand uses 20.

[MrPlaneDriver 41]

There's no right number for Cost Index. Anyway, the 737 family has a range from 0 to 199 (sorry, that range was valid to Classic Family -3/-4/-5). BBJs have 0 to 399 the same range of NG, from 0 to 499. For example, in Brazil we have a low cost called GOL, that uses from 8 to 12. TAM uses 12 to 15... Varig used to use 20 - 50 and so on... Ryanair must use ZERO! hahahaha

Really? I thought GOL used 25 as CI. Remeber reading that in their SOP. Well... that's an oooold SOP that dates back to 2007, so things may have changed. PS.: Sorry for the thread revival, guys. I didn't see the dates there. My bad.