As per the manual, I set the flight plan, etc. in the FMC. Before commensing the takeoff roll, I hit the VNAV button to arm the VNAV profile for autopilot. After bringing the throttles to about EPR 1.1, I hit the EPR button to engage the autothrottles. I then complete the takeoff roll and after leaving the ground, hit the A/P button to engage the autopilot.At this point, though, the plan hovers just over the ground at only about 1K feet with no ascent for about 20-30 seconds. It seems like the climb profile doesn't kick in until after this time. Because I retract the gear, I get "too low, pull up" warnings.I'm using the Fly flight-planner to create the flightplan. So embedded altitudes are from the flight plan. This appears to be the only problem as all other VNAV functions seem to operate properly under A/P.Am I doing something wrong?-DK----David KohlFly! II v230Dell 8200 P4/1.8G, 1024MB RAM, Nvidia GF4 Ti4600 v30.82, WinXP Home Edition.CH Pro Pedals and Yoke USB.

I don't believe the autopilot is designed to do an automated takeoff and initial climb-out. It is my understanding that typically the PIC will fly the aircraft to the initially assigned altitude before deciding whether or not use an automated nav function. If the real 757 autopilot can automate a takeoff and initial climb-out, I don't remember this function being tested during the 757 beta and I don't recall the manual stating any such function.George

Note: I'm not managing takeoff with the autopilot. I'm only looking to manage the climb as described in the manual. For example, on page 8-6 of the 757 Manual, the following text is written..."If on the ground, VNAV will arm to engage at 400AGL. If in the air, VNAV will engage, and the VNAV switch will illuminate. When the aircraft climbs through 400 AGL, pitch and speed control as well as autothrottle control will be transitioned to the FMC."And on page 10-4..."Under normal circumstances, VNAV will be armed prior to commencing the takeoff roll. As the aircraft passes through 250 feet AGL, the A/P should be engaged by pressing the A/P switch. VNAV will engage and take over the autopilot pitch mode at 400 feet AGL. The use of VNAV to manage the takeoff profile is the preferred method, provided the appropriate required VNAV route navigation data was entered."So it does appear that it was the intent to have VNAV manage the takeoff profile from 400 AGL and up. But for some reason, it seems that when I do as is written on 10-4, the "profile" is flat for the first few miles of flight (20 to 30 seconds) until the plane begins to climb. Of course, the plane picks up tremendous speed during this time since the throttles are at climb thrust yet the plane flies more or less level.By the way, this function works smoothly on the B777 using the same method of generating a flightplan (through the Fly!2 interface) and pressing the VNAV key before takeoff, followed by the A/P switch at about 250 AGL.Any help with the 757 would be appreciated.-DK----David KohlFly! II v230Dell 8200 P4/1.8G, 1024MB RAM, Nvidia GF4 Ti4600 v30.82, WinXP Home Edition.CH Pro Pedals and Yoke USB.

"Under normal circumstances, VNAV will be armed prior to >commencing the takeoff roll. As the aircraft passes through >250 feet AGL, the A/P should be engaged by pressing the A/P >switch. VNAV will engage and take over the autopilot pitch >mode at 400 feet AGL. The use of VNAV to manage the takeoff >profile is the preferred method, provided the appropriate >required VNAV route navigation data was entered."[/i] I found it very interesting. I wonder if this is in agreement with real Booeing/airlines procedures. 767 is not much different (actually identical cocpkit) but according to many 767 pilots (on 767PIC forum) you should NEVER arm VNAV on the ground. If you go to that forum and search there are very well in-depth written takeoff procedures for the 767 and VNAV is certainly not part of those procedures. There is also a website (www.smartcockpit.com) - by a 767 check pilot - that describes all major 767 procedures. But who knows, maybe 757 is different .... There is a 757 Capt. BBall on the PIC forum - you may ask him. He flies 757 daily for NWA.Michael J.

.. but having said that I agree that VNAV Fight Director should never give you a flat profile after takeoff. So it may be a bug. I used too arm VNAV on the ground using the 767PIC and it was working great but I stopped doing after I was told it is not being done in a real 767.Michael J.

VNAV is not giving a flat profile, because VNAV does not engage before 400 AGL.The pitch mode at takeoff should be TOGA if the FD is on. This is an FD assisted mode only on the 757 which will ONLY indicate on the PFD how to pitch to maintain V2+10 (or 15?) and will NOT steer the controls.Soooooooo, when you engage the AP, it engages at current VS, and stays there until 400 ft....Soooooooo, if you haven't, as you should, pitched to maintain V2 + 10 before engagement, it will not climb as by the books...Soooooooo :1) at takeoff pitch to maintain V2 + 102) when OK engage AP, or wait that VNAV engages before engaging the APhope this helps.anthonyAnthony MertonPrecision Manuals Developmenthttp://www.precisionmanuals.com

I'll give this a shot and record some screen shots just after takeoff showing the FD guide, pitch and altitude as I leave the ground.Thanks though.-DK----David KohlFly! II v230Dell 8200 P4/1.8G, 1024MB RAM, Nvidia GF4 Ti4600 v30.82, WinXP Home Edition.CH Pro Pedals and Yoke USB.

Anthony:Thank you for the above instructions. They worked. What I had been doing was selecting A/P while on the ground, expecting it NOT to engage until reaching 400 AGL. Try it, you'll see the results I got (low takeoff profile).NOTE: If one selects A/P while on the ground in the B777, it will automatically engage (appropriately) at 400 AGL, so there is a difference in how A/P works with VNAV in these two aircraft despite the manual reading very similarly.Thought I'd point that out.Again, thanks for the tips above.-DK----David KohlFly! II v230Dell 8200 P4/1.8G, 1024MB RAM, Nvidia GF4 Ti4600 v30.82, WinXP Home Edition.CH Pro Pedals and Yoke USB.

Well in fact I think one shouldn't be able to "select" the AP on the ground (at least that's what I understand from the various docs I read. Even the highly automatized A320 family's AP is not engaged before after TO)The AP itself, contrary to the autoflight modes cannot be "armed". If you request it it will either engage, or not, but won't wait for a given condition to be verified to become "active".Sooo, in principle, one shouldn't be able to select a VS or activate the AP on ground. If it's possible with our birdies, I'm afraid it's a bug(let).:-)anthonyAnthony MertonPrecision Manuals Developmenthttp://www.precisionmanuals.com

Try it in the B777. Press the VNAV button before commencing takeoff. After reaching 1.0 EPR, engage the autothrottles. You'll see that if you hit the AP button during the takeoff role, it'll automatically engage VNAV at about 400 AGL. I'll accept though that this behavior is an "add feature" of the PMDG 777. :-)Thanks again for being responsive.-DK----David KohlFly! II v230Dell 8200 P4/1.8G, 1024MB RAM, Nvidia GF4 Ti4600 v30.82, WinXP Home Edition.CH Pro Pedals and Yoke USB.

no no no no, this is exactly what I tried (and failed) to explain in my last post :the VNAV / LNAV autoflight modes function without for the need of the AP to be engaged.Try to arm VNAV (LNAV) on the ground, take off leaving the AP alone. You will see that if you steer by hand the aircraft following the flight director cues it will fly as if the AP was on ! Same for an ILS approach, BTW. If you have GS/LOC engaged you can hand fly the AC without the AP... ditto for FL CH...What is meant is that : when those modes are active *and* if the AP is engaged, then the AP will steer the AC following the FD cues. MEANING : the AP is fed by the FD, which is fed by VNAV LNAV etc, not the opposite... It is at the very botton of the chain (well, excepting the servos moving the control surfaces)Think about the AP as just a middle-man steering the AC *on the basis* of what the flight director displays on the PFD. The FD does not care a bit if the AP is engaged or not. It gives guidance, according to what the FMC/MCP tell him to do, that's all.Now, coming back to this strange 757 TOGA takeoff FD mode : it is assisted only, meaning that is implied that if the AP is engaged, the vertical mode is switched from TOGA to VS (default), if VNAV has not engaged (i.e. was armed and the AC is over 400ft), otherwise VNAV is followed. Rather bizarre but that's the way it is. Maybe a real life 757 pilot could kick in...I know, it's not easy stuff for non-professionalsbut hey, we've got time to learn :-)anthonyAnthony MertonPrecision Manuals Developmenthttp://www.precisionmanuals.com

Actually, you did a fine job in the last post (and the manuals also do a find job) of explaining how the FD's and A/P interact. So maybe it was just my writing that was unclear.----While I have you engaged, I have a question about B777 development. There is a minor bug with the aircraft tail and wing lights. They shine into the sky, rather than to the wings and tail. When the 777 was released, Rob had suggested that in an upcomming patch, this bug would be addressed. I know most (or maybe all) Fly!2 development has come to a halt, but would you guys consider patching the 777 to rectify this minor visual bug? I won't even ask about creating a work-around for the B757 day/night textures problem since it appears that Fly!2 will never be patched to accomodate the texture issue.Thanks. A quick response is appreciated, and I promise not to start another annoying thread on patches.-DK----David KohlFly! II v230Dell 8200 P4/1.8G, 1024MB RAM, Nvidia GF4 Ti4600 v30.82, WinXP Home Edition.CH Pro Pedals and Yoke USB.

David,See the "NEWS FROM PMDG REGARDING FLY.... 22OCT02" post in this forum.Bye for nowanthonyAnthony MertonPrecision Manuals Developmenthttp://www.precisionmanuals.com