I have hotfix 3 I've just performed a couple of take offs with both acceleration and reduction heights set to 800ft on Takeoff 2/2. A/T was on but no roll or pitch modes were selected. TO/GA was used for take off. Autopilot was not engaged until after levelling off at 6000ft Take Off 1:When I reach 800ft, thrust = CLB 2 (N1) so I bug up to flaps up speed (209) and the FD bar moves down for acceleration. I clean up and reach 209 kts by around 2100ft however the speed continues to increase to around 234 kts by 3000ft agl if I continue to follow the FD. The MCP speed window is still showing 209 kts. TO/GA mode disengages when I reach the MCP altitude of 6000ft. Take Off 2:When I reach 800ft, thrust = CLB 2 (N1) so I select LVL CHG which changes the pitch mode from TO/GA to MCP SPD and I then bug up to flaps up speed (209) and the FD bar moves down for acceleration . I clean up and reach 209 kts by around 2100ft and this speed is maintained if I follow the FD with a gradual increase in climb. At 3000ft agl I bug up to 250 and reach this at 5200ft agl, once again the speed is maintained until I level off at 6000ft when A/T changes from N1 to MCP SPD. So this seems to confirm what the OP said: "Before the newest hot fix the flight director would lower its pitch to tell me to accelerate to the new speed I have selected. Now it just keeps the takeoff pitch and doesn't lower." - Except that you over accelerate. So the remaining item of debate is that Sylvain says you shouldn't have to select a pitch mode to accelerate, by simply changing the MCP speed you should be able to accelerate and maintain that speed throughout the climb by following the FD in TO/GA mode.

Ryan, You might wanna re-check this again with your technical pilots as your statement is actually wrong information...HF4 behavior in incorrect! After reading the big write-up thread I agree with your statements about the behavior of the speed bug on the speedtape and the MCP speed value. I disagree when you say that acceleration has to be made in LVLCH or VNAV and cannot be done by following the FD in TOGA mode.I'm even more surprised by this statement as it's actually standard Boeing SOP to accelerate for flap retraction with the FD still in TOGA and to exit the FD TOGA mode by switching to VNAV or LVLCH after flap retraction. When the MCP speed value is increased ABOVE V2 (which was set for takeoff) with the FD still in TOGA pitch mode, the FD pitch bar should drop to command an acceleration towards that new speed. Note that the increment of 20kts is only commanded as long the MCP speed value is left at V2. Once the MCP speed window value is increased, both the value in the MCP and the speed bug on the MCP jump up 20kts (and continue to increase from there afterwards) and the FD in TOGA pitch mode commands an acceleration towards the new speed (no longer +20kts) Best regards, Sylvain Coolsaet Ps: @Tabs: Support Ticket Ticket Number 1E5-1625CAC9-F137 will peak your interest I guess...

Sylvain is right Ryan, even not selecting LVL CHG or VNAV, when at acceleration height and selecting Bug Up speed on MCP the FD should command a nose down pitch towards that selected speed. That's how it's done, it's clearly shown on FCOM and SOP's worldwide.

Hey guys. Ryan meessaged me last night about this. Sorry, back when this was being discussed there might have been some miscommunication, or misunderstanding, between Ryan and myself. Thats what i dislike about texting. Its easy to do. So yes, the FD should command whatever is set in the MCP window even if the mode is still in TOGA. Initially it will be V2+20 until you manually change it.

Hey guys. Ryan meessaged me last night about this. Sorry, back when this was being discussed there might have been some miscommunication, or misunderstanding, between Ryan and myself. Thats what i dislike about texting. Its easy to do. So yes, the FD should command whatever is set in the MCP window even if the mode is still in TOGA. Initially it will be V2+20 until you manually change it.

To clarify: Initially you will have V2 set in the MCP speed window for take-off. At lift off the FD initially commands 15 degrees nose up, then as ROC builds it commands a pitch which will give a speed of V2+20 even though you still have V2 set in the speed window. At acceleration altitude you set 'UP' speed in the speed window & the FD pitch bar should lower to command you to lower the nose & accelerate to 'UP' speed so that you can retract the flaps. The problem with the NGX at the moment is that the FD is not giving this lower pitch command at this stage & so if you continue to follow it you will not accelerate. Another problem is that, before you reset the speed to 'UP' speed, the underspeed symbol is flashing in the speed window: this should not be occuring. Cheers, Doug

Safe to assume this will be resolved once and for all... hopefully, in sp1?

Well, since parts of it have been resolved (or should I phrase it "changed") since HF4, we might hope for more fixes (I hope).

To clarify: Initially you will have V2 set in the MCP speed window for take-off. At lift off the FD initially commands 15 degrees nose up, then as ROC builds it commands a pitch which will give a speed of V2+20 even though you still have V2 set in the speed window. At acceleration altitude you set 'UP' speed in the speed window & the FD pitch bar should lower to command you to lower the nose & accelerate to 'UP' speed so that you can retract the flaps. The problem with the NGX at the moment is that the FD is not giving this lower pitch command at this stage & so if you continue to follow it you will not accelerate. Another problem is that, before you reset the speed to 'UP' speed, the underspeed symbol is flashing in the speed window: this should not be occuring. Cheers, Doug

I simply can´t reproduce this erroneous behavior on my end. Maybe it´s because I´m arming Vnav on the ground and letting it kick in automatically at accel height (which per my sop usually coincides with accel height). But as soon as Vnav becomes the active mode in the FMA, my MCP speed window goes up automatically to 230kt, and FD lowers the pitch. Clearly, it´s trying to get me to accelerate. I haven´t tried doing it the old way (N1, bug up, lvl chg), but then again, why should I? After all I got a spanking new FMC software that every 738 crew around the world would love to have in case they´re flying the oldies Now that I worte this, it reminds me of a quesiton: if at accel height I engage vnav in case it wasn´t armed on the ground, do I still need to bug up an press N1? It seems to me vnav would take care of these things, no? What about Matt´s SOP of pressing N1 at thrust reduction? Is that necessary after 10.8?

I simply can´t reproduce this erroneous behavior on my end. Maybe it´s because I´m arming Vnav on the ground and letting it kick in automatically at accel height (which per my sop usually coincides with accel height). But as soon as Vnav becomes the active mode in the FMA, my MCP speed window goes up automatically to 230kt, and FD lowers the pitch. Clearly, it´s trying to get me to accelerate. I haven´t tried doing it the old way (N1, bug up, lvl chg), but then again, why should I? After all I got a spanking new FMC software that every 738 crew around the world would love to have in case they´re flying the oldies Now that I worte this, it reminds me of a quesiton: if at accel height I engage vnav in case it wasn´t armed on the ground, do I still need to bug up an press N1? It seems to me vnav would take care of these things, no? What about Matt´s SOP of pressing N1 at thrust reduction? Is that necessary after 10.8?

Well, why should you: Because IMHO an add-on is a good add-on when it behaves correct under all (or at least most) circumstances, also when leaving your very SOP. Say I can shutdown my engine in flight (certainly not quite SOP...), and restart it using various methods, including bleed air assisted and windmilling start. Not SOP, but it works. (I know, bad comparison, but still ) And obviously you can't repro this behavior when using VNAV, after all the issue's about pitch guidance in takeoff mode. With VNAV active, you're in an entire different mode set, which, AFAIK, works as it should at this point, namely accelerate at acc alt (and command that via FDs as well). If you engage VNAV at acc height, you don't have to hit N1 because it comes on together with VNAV. Also, as Matt has mentioned before (IIRC), it's not necessary to hit N1, but you can still do it at acc alt if you opt to and plan to use VNAV only after flap retraction, which, BTW, is also SOP for some.

What about Matt´s SOP of pressing N1 at thrust reduction? Is that necessary after 10.8?

I've been flying a mix of planes -4,-7,-8,-9, and some with U10.7 and some with U10.8A. I think you wouldn't need to hit N1. But I've not done a non-VNAV takeoff in U10.8A.

Well, why should you: Because IMHO an add-on is a good add-on when it behaves correct under all (or at least most) circumstances, also when leaving your very SOP. Say I can shutdown my engine in flight (certainly not quite SOP...), and restart it using various methods, including bleed air assisted and windmilling start. Not SOP, but it works. (I know, bad comparison, but still ) And obviously you can't repro this behavior when using VNAV, after all the issue's about pitch guidance in takeoff mode. With VNAV active, you're in an entire different mode set, which, AFAIK, works as it should at this point, namely accelerate at acc alt (and command that via FDs as well). If you engage VNAV at acc height, you don't have to hit N1 because it comes on together with VNAV. Also, as Matt has mentioned before (IIRC), it's not necessary to hit N1, but you can still do it at acc alt if you opt to and plan to use VNAV only after flap retraction, which, BTW, is also SOP for some.

Thnx for the clarifications Etienne. From what I gather Matt´s airline does it that way so that all departures comply with NADP-2. What I have trouble grasping is why they press N1. I thought it was still being done because there are NGs flying around without the latest FMC update where you have to "manually" enter thrust reduction and acceleration height via MCP. (namely, pressing N1 would get you out ot TOGA thrust and establish climb power, while setting top bug would tell the airplane it has reached accel height, correct?). From what I remember these older FMC softwares don´t even have an accel height thrust reduciton parameter in the T/O pages.

I've been flying a mix of planes -4,-7,-8,-9, and some with U10.7 and some with U10.8A. I think you wouldn't need to hit N1. But I've not done a non-VNAV takeoff in U10.8A.

Well you replied to me while I was posting, that was quick. Thanks for the answers!

Yeah, U10.7 Takeoff 2.2 has RWY SLOPE and WIND, only I think. We don't use it anymore with the automated takeoff performance reports.