August 15, 201114 yr In the top pic you are using the Honeywell MCP with both VNAV and LNAV selected.I think that is the problem. I am presuming you are using TOGA for takeoff ? The bottom pic is nothing unusual if you try and fly without FD's on. Fred. FD bars have nothing to do with autopilot being on or off !! Fred. I know that, but by the pic if he engaged the autopilot the bars would have came up... .. It's difficult to tell by a few pictures without someone explaining in detail about how they programmed the flight..
August 15, 201114 yr Author I know that, but by the pic if he engaged the autopilot the bars would have came up... .. It's difficult to tell by a few pictures without someone explaining in detail about how they programmed the flight..No they wouldn't. In fact good that you mention it because it was another "issue" within what I've been describing above. Under said circumstances the AP would not engage at all. Now don't tell me to trim the aircraft and if that doesn't help check failures and even disable realistic AP engagement - I sure know about that. It didn't work. It "blinks" on for the fraction of a second but turns off immediately, just as if engagement criteria were not met. I'm a litte lost here, it has happened numerous times and there were exactly zero anomalities during preflight or setup.
August 15, 201114 yr No they wouldn't. In fact good that you mention it because it was another "issue" within what I've been describing above. Under said circumstances the AP would not engage at all. Now don't tell me to trim the aircraft and if that doesn't help check failures and even disable realistic AP engagement - I sure know about that. It didn't work. It "blinks" on for the fraction of a second but turns off immediately, just as if engagement criteria were not met. I'm a litte lost here, it has happened numerous times and there were exactly zero anomalities during preflight or setup. Hey man, just trying to help.. What was your flight plan? I have some time, I'll try to recreate it for you..
August 15, 201114 yr Author Hey man, just trying to help.. What was your flight plan? I have some time, I'll try to recreate it for you..Hey yeah, I appreciate it! I don't remember the exact FPL as I took the screenshots a few days ago. I'm pretty sure I will come across it though and then I will make sure to collect data. Stay tuned and thanks for the help.
August 15, 201114 yr Author Alright back to the second thing quick, just made a quick and dirty video, excuse the miserable quality I have no idea what I shall use to record better. Seems the very first beginning got cut off too, as AT appears off right at the beginning. At least you can see my clicks by noting the occasional red circle around the mouse cursor. It's all taken during manual flight, and we see a normal cruise here (at 4000 admitted, but nonetheless a cruise). Manual flight, AP stays off during the whole video. Watch FMA at the beginning. Disengaging the only active FD kills LNAV. Note no FD is now active, as is AT and AP. FMC SPD and VNAV still "active".Hitting VNAV button kills VNAV PTH.Engaging AT changes FMC SPD to ARM. At 0:40 everything is finally off. Then I reengage FD L, LNAV, VNAV. Watch FMA (should FMC SPD be active here? Remember AT is off). Disengaging FD gives me now the issue I originally meant. VNAV PTH stays "active", this time without FMC SPD (???).Again, VNAV can be killed by button push and not be reengaged (luckily). Everything off again, and at 1:15 I start reengaging FDs and AT. LNAV and VNAV follow. Watch FMA (same as above!).This time I switch off AT first (1:30). Now FMC SPD vanishes (should it not have done this above as well, actually not even have engaged with AT off?? *).Killing FDs will, again, kill LNAV, while VNAV stays active. Last action is to disengage VNAV by button push. Here's the link. * FCOM, AT Engagement:Moving the A/T Arm switch to ARM, arms the A/T for engagement in the N1, MCP SPD or FMC SPD mode. [...]A general summary of A/T mode engagement is as follows:[...]- engaging LVL CHG or VNAV climb modes automatically engages the A/T N1 mode...- engaging LVL CHG or VNAV desent modes automatically engages the A/T in RETARD and then ARM when thrust is at idle...- if not in a VNAV mode, [...] otherwise the A/T remains in FMC SPD Alright, but isn't this all presumed by an ARMED autothrottle system? Next paragraph, titled Autothrottle disengagement: Any of the following conditions or actions disengages the A/T:- moving the A/T Arm switch to OFF[...] Also, and most importantly, from a few pages before:All AFDS modes can be disengaged either by selecting another command mode or by disengaging the A/P and turning the F/Ds off. Wow confusion really adds up on my part here. If everything in this video is as it should, then I've got a whole lotta reading to do. Reproduce as indicated, starting point is a normal cruise, nothing fancy. I'd be glad to hear about your findings.
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