Auto Pilot '737 Pilot in Command'

[Timvee 0]

Ahaa!! I can feel success looming!! If you can change heading with the heading dial and the A/T is working fine, then it sounds like the problem is solely with the altitude control and not the A/P per seWhen you've finished 'screenshotting' try it agin focussing on the 'CMD - ALT' sequence - in that order!CheersTim

[martinboehme 492]

Phil,> I just have done that did my trip from Heathrow to Brussels, I had to fly the whole way the manualy....well, at least that means you're keeping up your hand-flying skills... who needs autopilots anyway? ;-)Cheers,Martin

[Guest Pinkgin]

Okay GuysAt the moment my screen shot thing does not seem to work! will have to wait till my wife gets back from work to figure that one out for me!At the moment I'm flying level at 4,200 ft at 250kts,and all is trimmed perfectly. BEFORE I engage A/P on the EADI I have showing MCP SPD/BLANK SPACE/HDG SEL/FDand on the MCP A/T is armed, FD is on, speed light is on, hdg sel light is on. WHEN I ENGAGE A/P on the EADI there is MCP SPD/ALT HOLD(in a white box)/HDG SEL/CMD. I did also engage Alt hold AFTER engaging A/P and the plane shot upwards into a steep climb!Phil

[Timvee 0]

Phil, great! So 2 questions.1) Did the a/p get you to and keep you at your set altitude?2) How steep is steep?The reason I ask is that if the plane is at its dialled speed and needs to climb it will seek to maintain the best rate/angle of climb. So for example if you've dialled in 250kts, when it gets to that speed it might start to climb at a rate as high as 4k feet per minute - but not for long because what would then happen as its angle of climb increased is that its IAS would decrease. It would then pitch down to increase IAS and go up again when it reached target speed. It's a safety thing ... low IAS = slow down = stall = BUMP! It is actually re-trimming itself to climb as quickly as possible within the limitations of thrust, speed and the lift that is being generated, continually balancing speed and climb angle.So quite possibly it behaved exactly as it should have done.We're getting there!Tim

[martinboehme 492]

Phil,those autopilot annunciations are quite helpful, but a bit puzzling...The second box (as you've probably figured out) tells you your pitch mode. I.e. before you engaged the autopilot, you didn't have a pitch mode selected. This shouldn't really be a problem, because the autopilot automatically goes into ALT HOLD mode when you engage (the white box is there to alert you that an autopilot mode has just changed). Why it should then go into a climb is a mystery to me, though... did this happen when you first engaged the AP or only when you pressed ALT HOLD?Can you try pressing ALT HOLD _before_ you engage the AP? What does the pitch bar of the FD command in this case? (It's good practice to have the desired modes selected before you engage the AP to avoid any surprises...)Cheers,Martin

[Timvee 0]

Now this is interesting. I've just done a quick nip around Seattle to 5000'then 7000' with just the a/p engaged, no lights. But as Martin said the alt hold was working even though I hadn't manually engaged it.Wonder why it dived the first time? However the rapid climb still occurs if you are at your required speed then need to climb to a higher level.I know this program still has bugs e.g sometimes, very occasionally, N1 drop off on finals - I wonder if this could be another?I'm nipping over to the feelthere forums to take a look!Tim

[Guest Pinkgin]

God, you chaps are great you know!I will have to give this another try tomorrow afternoon! I will print off all your emails and have a read in bed tonight. I'm sure that you have just about got me fixed!When I was level at 4,200 what ever it was and set the A/P the plane shot up very quickly into a stall this was even before I set the Alt switch. At the time the Alt was set for 11500ft.I tried it again with the Alt switch turned on before the A/P and the same thing happened!..mmmmmmmmmmI was just wondering if one of you very kind guys could set me an identical flight that you have done and give me in detail right from the start what you did with the controls and buttons to the moment you set your auto-pilot. I will then copy it. I know its a big pain for you but that surely MUST work!!??Thanks you so much Martin and Tim

[Timvee 0]

Phil,I'm going to do EGKK-EGCC at CRZ 20000.- It's nice and short!I'll let you know the steps as soon as I've done it.Tim

[Guest Pinkgin]

Thanks very much for that Tim!Phil

[Timvee 0]

Right Phil;1. select aircraft, fuel, make note of fuel and zero fuel wieight.2. At gate, engines on.3 FMC pos ident. scratch EGKK click LSK 2L.4 click route.5. LSK 1L EGKK LSK 1R EGCC click on route request. click activate click 'exec' button click perf init6. scratch 99.0 click zfw. 3.0 click reserve 30 click cost index 200 click LSK 1R 6000 click LSK 6R click 'exec' button click N1 Limit7 N1 Limit (leave and just click Take-off)8 Take-off - Enter Vspeeds (for gw of 118.9) v1 137 vr 139 v2 1499.Click CLB button click max rate click 'exec' button10. Click CRZ button click 'econ' click 'exec' button.11. Check altitude dialled to initial clearance level and speed at v2 + 10 (160 'cos I rounded it up!)12. Check F/D and A/T on.13 Trundle to runway. Set flaps to 5 and autobrake to RTO14. Line-up.15. Push TOGA - hurtle down runway take off as normal.16 At 'positive' retract gear At 1000' clean up.17 when ready click 'CMD' check all lights on.I've not bothered with the lights or SIDS and STARS- this was a test flight!!! Good LuckTim

[Guest Pinkgin]

Tim,Brilliant, thanks.....can't wait to try that later!Phil

[Guest _ak]

If you have dives, "Invert elevator" checkbox in config utility right at 1st page could help

[Guest Pinkgin]

_ak Thanks for that.Phil

[Guest Pinkgin]

Hello Tim,Okay I have tried it and again No luck!!In your list I had a problem with No.6 when you said 6000 click LSK 6R could not see that? what is it?Got everything else though...I took off perfectly and tried the A/P still it dived big time tried lots of times again same problem each time. Tried many variations on the Trim still no luck at one point when trim was as far back as it would go the plane climbed but A/P still not doing what it should!When reaching 20,000 I had the plane trimmed almost perfectly hand off the stick.... tried to engage A/P......the plane whent into an immeadiate dive!Wow what on earth is happening???!!!On EADI before engaging A/P there was N1/MCP SPD/HDG SEL/FDOn EADI after engaging A/P there was MCP SPD/ALT HOLD/HDG SEL/CMDCheersPhilPS. By the way what are SIDS and STARS ??....Please.

[Guest Pinkgin]

I have just been looking at the assignments list and seen this:!!A/P Alt Hold on/off.....CTRL+ZA/P App Mode on/off.....CTRL+AA/P Attitude Hold on/off.....CTRL+TA/P Back course Mode on/off.....CTRL+BA/P Heading Hold on/off.....CTRL+HA/P Localizer Hold on/off.....CTRL+OA/P Master Switch on/off.....Z (This is what I have always used)A/P Nav1 Hold on/off.....CTRL+NA/P Wing Leveler on/off.....CTRL+VI have only been using just key Z to engage the A/P is that RIGHT? may be this is where my problem is??Phil