init ref 737 problem

[Guest HaPpo]

Hi everyone and thanx in advance for your attention!I have installed the 737 ng and I've a problem:the fmc don't sign correct vertical speed for the takeoff...I mean I have done any passage correctly, I set all weight parameters but the fmc don't return on the screen the vertical speed so I can't prepare a correct takeoff.Someone can help me?HaPpo

[downscc 1,327]

Vertical speed for takeoff?Maybe you're missing V1, Vref & V2, which happens if you don't have a pre-flight complete message in the middle of the init ref screen. Most common problem (assuming cruise alt and weights are done) is not selecting departure or departure runway.Vertical speed isn't directly used for control of flight.

[crvm 0]

To add further - if I understand your question correctly, you simply need to fill in all the BOXES which are required or the FMC to calculate the profile perameters correctly. After that, LEFT CLICK on the VREF Line Select Keys on the RIGHT side of the CDU. This will put the VREF speeds in automatically.Best,Randy J. Smith

[Guest HaPpo]

Thanx 4 your replies...sorry for my english...I mean:In 737ng version I fill in all boxes required...and the fmc return the vref correctly when I left click the line select keys, but in the option addon 737 800/900 the same procedure don't put the vref speed automatically (on the center screen of my fmc pre-flight is complete and the route is correctly planned)...maybe change something?Also when Vnav on the mcp remain off and the aircraift seems too heavy for takeoff and somentimes go long over the runaway (but i have correctly used the load manager...).Maybe, Do you have some good tutorial to suggest me? Or some dedicated passage on the original manual...thanx againHaPpo

[downscc 1,327]

Your English is better than my ability to speak anything other than English.You have to fill in all the required boxes, as mentioned before, but you must also select a departure runway. Even if you don't select a SID the FMC still wants a departure runway before it gives you the V-speeds.The first thing to check if the aircraft is slow to rotate regardless of speed is trim. Always set the trim when doing preflight, if it is too low the airplane may not rotate at all. The trim on the -600 is about 4.5; the -700 is about 5.5; and I don't remember the best trim for the 800/900 but I expect it to be about 6.0 deg.Both of these items are "minor details" that I have had to learn through experience rather than reading. They are in the books but are not highlighted as important, but they will cause the problems you are describing.Hope this helps.

[Guest HaPpo]

thank you...like I said the route is well done insert, like the departure runaway and the sid, legs and destination with the correct star.But fmc don't return automatically the vref...Maybe trying and trying I'll find some mistake...I read same tutorial in this days, they explain preflight operation quite well but my vref boxes continue to be blank...so I ask if someone had the same problem and knows the solution.I appreciated your attention.thanxHaPpo

[downscc 1,327]

This is interesting. The only error I know that will inhibit V-speeds when you have the preflight complete message is an unselected departure runway; but you have selected runway and you still have this problem. That is why it is interesting.You also said you don't have this problem with the -700; I have not had this problem, but if I did I would look for something I missed. Forget assumptions and verify everything, make sure all "empty boxes" on all screens are gone. I would try saving a company route that works with the -700 and load it into the -800. I would try doing the preflight with engines running, generators on line, even tho this should make a difference.I have assumed that you have successfully got the automatic V-speeds at least once since you installed the 800/900. Is this true?

[Guest HaPpo]

yes, correct!I had think that some procedures are different but it seems not sonow I'm going to verify with a tested route.Weight paramaters are different, but I'm going to make the test you suggest me.Also I try with the aircraft with engines running and generators on line.I'll post after test.thxHaPpo

[Guest HaPpo]

Ok, It's run.I really don't know how but now also 800 and 900 are ok.I play like suggest...Thanx you very much guys.