Installed the 800/900, and did a few flights and noticed something about VNAV approaches. On the 600/700 the aircraft would follow the flap/speed restrictions on the descent page at LSK4(SPD REST.)the 800/900 doesn't seem to do this. When I stay in VNAV I see no XXX/FLAPS restrictions as I deploy the flaps.It should do this:-destination airport speed limit -10-Waypoint speed restriction if greater than flaps up manuevering speed-min flaps up manuevering speed.-selected VREF+wind corr for landing flaps.-whenever flaps are deployed the the appropriate XXX/flaps. Should this be the minimum flap manuevering speed? Such as VREF40+10 for flaps 25 and 30 for instance.It seems like speed restrictions at waypoints are over riding flap speed restrictions on descent.

The only thing I can think of is that VREF wasn't set correctly in the INIT PERF page before descent. Then again, the 800 is new to me too, and I usually end up manually setting things anyway because of the dang ATC (note to self: reminder to tell pilots to change speed / alts for PMDG arrivals to keep'm on their toes :))Regards,

On the DES page the line showing the current speed is what is commanding VNAV. So if you have FD on and VNAV slecetd it will give you a pitch attitude to attain the speed displayed. When you pass the point in space at which the FMC wants you to DECEL and extend Flaps then it will show the Minimum Manouevring Speed for your cuurent Flap setting and this is a prompt to extend Flaps to the next flap position and you will then see the speed change accordingly.Another way to look at it is the FMC is prompting you to extend the flaps for it because it can't do it itself.Make sense?Brad Marsh

No ,VREF was set it just isn't following the flap restriction speeds but its sticking to the waypoint speed restriction.Im fairly sure flap restriction speeds if lower than waypoint restriction speed will be what VNAV follows on approach, like I said the 600/700 version 1.3 did this.EDIT- Im not seeing this Brad the speed stays at the current waypoint speed, say that Im at the OM and have a speed restriction of 180/2000 in the FMC and prior to that I go flaps 30, I should see a XXX/flaps speed but its staying at 180Kts even though I have flaps 30. Is this correct?

VERY GOOD QUESTION Wallace! Why? Because I asked the same thing and still I do not have a CLEAR ANSWER from anyone who flys the bird. I **think that once someone has set flaps on final the FMC should NOT speedup to a wpt restriction but this is only a guess, hell it could be the correct way seeing the the NG is very different than even the classic in this area (like on TO it IGNORES the FLAPS/XXX) and shoots straight to climb page restrictons like the airport restriction. So hopefully we can get some clear official answer from a NG pilot of AOMS etc.. [h4]Best Wishes,Randy J. Smithhttp://www.precisionmanuals.com/images/forum/betaimg.jpgAMD 64 3200+ | ASUS KV8 DELUXE | GFORCE 5700 ULTRA @535/1000 | WD SATA 80 GIG | 512 DDR 400 |

Thanks Randy, but Im fairly certain it will follow the flap handle in VNAV when doing a GPS/RNAV approach. Its funny I couldn't find a real clear answer on this either, alot of the QRH's, FCTM's and Op's manuals are really not very clear on certain things and contradict each other.Really enjoying the 800/900 otherwise, its better than I ever thought possible in flightsim.

Well it does do this while you are setting FLAPS, the issue is when you are DONE setting flaps and prior to the FAF or any other restriction with a SPD restriction attached to it. [h4]Best Wishes,Randy J. Smithhttp://www.precisionmanuals.com/images/forum/betaimg.jpgAMD 64 3200+ | ASUS KV8 DELUXE | GFORCE 5700 ULTRA @535/1000 | WD SATA 80 GIG | 512 DDR 400 |

Ok just tried a flight and sure enough after the last speed restriction in the flight plan I was able to control the speed with the flaps, but prior to that no matter what flap setting I choose, speed would not change from 240kts prior to reaching the last waypoint speed restriction. I dont know but this just doesn't seem right to me.Flaps surely must have priority over a waypoint speed if VNAV flap speed is lower than a waypoint speed restriction on the approach. It worked fine in SU2(did someone find this was incorrect?) ,was this changed in the 800/900 upgrade for this reason?

I think I am going with you on this one Wallace. After reviewing all the information I have on the subject it appears that VNAV is flaps driven speeds until G/S at which time the IAS window opens and displays last restrictive speed which would be for FLAPS. [h4]Best Wishes,Randy J. Smithhttp://www.precisionmanuals.com/images/forum/betaimg.jpgAMD 64 3200+ | ASUS KV8 DELUXE | GFORCE 5700 ULTRA @535/1000 | WD SATA 80 GIG | 512 DDR 400 |

Good Q. I was wondering the same??

I have put this question to the team to review. I do believe it is incorrect but will wait until one of the pilots confirm this difficult question.[h4]Best Wishes,Randy J. Smithhttp://www.precisionmanuals.com/images/forum/betaimg.jpgAMD 64 3200+ | ASUS KV8 DELUXE | GFORCE 5700 ULTRA @535/1000 | WD SATA 80 GIG | 512 DDR 400 |

Hi Randy et al.It is not normal to set a speed restriction unless it is an ATC or other requirement. Once you 'harden up' a speed then it will command the AFDS to hold that speed reagrdless of what you do with the Flap handle.Probably best if we were able to discuss this using voice in real time as these are complex areas that cause some confusion even to guys who fly the real aircraft. Many of the things guys talk about here just aren't done in teh real world so we need also to keep that in mind :)I would be happy to host a voice session on an AVC channel, Teampseak, Ventrilo or even Netmeeting.ATB,Brad Marsh

Once you 'harden up' a speed then it will command the AFDS to hold that speed reagrdless of what you do with the Flap handle. That's what I wanted to hear Brad ;-) You are correct that we are letting bad sim habits become real procedures and while certain things can be done differently other things like VNAV prior to flap retraction is simply not done on a NG (America West's 300 can and do) and this should be clear to all who ask and then wonder what is going on with the target speed when that's exactly how it works in the real bird. I mean it's great to know what can happen for a simulator but I think promoting some semblance of real world procedures is a great thing sir. I would love to talk do you ever Roger Wilco? [h4]Best Wishes,Randy J. Smithhttp://www.precisionmanuals.com/images/forum/betaimg.jpgAMD 64 3200+ | ASUS KV8 DELUXE | GFORCE 5700 ULTRA @535/1000 | WD SATA 80 GIG | 512 DDR 400 |

Ok ,I can live with that if its correct, will change my procedures then. I'll try have a word with our pilots and flight analyst when I have a chance. Thanks guys.

>Ok just tried a flight and sure enough after the last speed>restriction in the flight plan I was able to control the speed>with the flaps, but prior to that no matter what flap setting>I choose, speed would not change from 240kts prior to reaching>the last waypoint speed restriction. I dont know but this just>doesn't seem right to me.>>Flaps surely must have priority over a waypoint speed if VNAV>flap speed is lower than a waypoint speed restriction on the>approach. It worked fine in SU2(did someone find this was>incorrect?) ,was this changed in the 800/900 upgrade for this>reason?I don't know... as long as your speed is less than the limit speed for the flap setting, if you have a hard speed restriction for a waypoint I think the FMC logic would respect that.