Question regarding autoland3

[Guest Takechan]

HiI've been trying out the autoland function and i'm going through some trouble on some airports. I usually plot in a navfix for the runway i'm heading to in the FMC and then align and use autoland3. But on some airports it's not aligning correctly vertically and lands the 747 100-500 feet (maybe more sometimes) before the actual runway starts. I'm thinking I did something wrong with the "baro bug"? Thanks for the help, i've been going through the type rating courses and the operating manual trying to find some answers, but to no avail :'(- Takenobu Tou

[claviermichel 0]

Hi There,ssssst... Listen before you get nuked by the guards there is a custom here (some call it a rule) which impose posters to sign their messages with their real name.To your question now, are you using any weather when flying? are you using the correct DA for the specific runway you are trying to land on?Can you give us more details as to which airports / runways you are having these difficulties and maybe interesting to know too which aircraft you are using.Best regards

[Guest Takechan]

Ah i'm sorry, I didn't think there were specific rules, that's my own fault for not checking that first. I'm using real weather data (15 min) from the FSX settings. I'm flying the PMDG B744 and last time I was trying to land at 27R at EGLL. I flew from my departure airport directly to LOGAN (fix) and had ILS27R in FMC (DEP/ARR).So when I aligned with 27R from the fix LOGAN I hit the LOC and the AP with L/V NAV checked. It aligned perfectly with the lateral part of the GS but it was too far below the glideslope vertically, and it didn't stay on the alt to capture it, meaning it tried to land me in the buildings short of the runway. It disregards the information in the legs when it's set to autopilot right? I was thinking that when DEP/ARR was set correctly and it had caught the localizer it would know if it was too low or too high. But I think i'm doing something wrong here... - Takenobu Tou

[FLEX1978 373]

A screenshot would help us figure out your problem. Are you sure LOC is captured and your not just flying the LNAV VNAV path to the runway? When the Aircraft captures the localizer that is lateral path. You need to be on the Glide slope for a correct vertical path (with your altimeter set correctly)Rob

[craig_read 43]

Sounds like you're not using the correct vertical navigation mode. If you're landing in Autoland the modes should indicate LOC for lateral and G/S for vertical. If you have anything else on there it's not landing properly.My understanding of the approach is as follows... 1 - Turn towards the runway to intercept at 50 degrees or so from the runway heading... when cleared to intercept localizer, select LOC on the MCP.. Usually at this point speed is under manual control and I dial in my required speed... probably 180 to 200 depending on traffic.2 - As the aircraft lines up with the runway and you tell ATC, they will clear you on the ILS approach, at this point I arm APP.. and check LOC is green and G/S is armed in white on the MCP.3 - Once the aircraft pitches down for the glideslope descent I set the MCP ALT to my missed approach altitude.. Usually at this point at 160knts.. Wait for the 3 autopilots to become active too..4 - At 4NM to go (common practice I believe for separation) I reduce to landing ref and at this point my flaps etc should all be configured.If you're LOC is working it suggests you're using the right ILS frequency so I would say it's not that. If your modes are not LOC and G/S with ROLLOUT and FLARE armed for lateral and vertical control, you're not in an autoland configuration.. VNAV should not be armed or active on the final descent to the runway.. You should see LAND3 on your PFD too, not CMD... CMD is not a landing autopilot mode.. I'd really need to see screenshots of your FMC legs page, MCP and PFD to see what was happening..Hope this is of some help, put up the screenshots and we can help..CheersCraig

[craig_read 43]

It is highly likely you're using your VNAV mode to land with, often approaches to runways within the FMC contain detailed height data that guides you to the point of touchdown. Often you'll see legs with 614 feet, 214 feet, etc.. If you're in VNAV and your MCP is set to 0 feet, then VNAV can continue to descent as the vertical path within the FMC instructs it to unrestricted. But VNAV is NOT.. a landing mode, it will not flare, it will ignore the glideslope and it will not work.. Sometimes you want to go manual you can let VNAV do it's job down to a low altitude and then take over manually for the final few miles.. However I'd always prefer to use the ILS even for that..CheersCraig

[Guest Takechan]

Ok thanks for all the replies, I think you are right that I might be using the LNAV/VNAV incorrectly, so i'll try again and see if I can take a screenshot of my landing. Thanks for all the help!- Takenobu Tou

[Guest Takechan]

Ok so I tried again, landing at EKCH 04R. I had put in the fix RNAV FIX BASLO and landed successfully!I took two screenshots:1) 2D Cockpit - http://i26.tinypic.com/2v3mutz.jpg2) Virtual Cockpit - http://i31.tinypic.com/2v331gm.jpgI noticed it did switch correctly from CMD to LAND3 and displayed rollout/flare. Please disregard the fact I forgot to extract my flaps to 20...Thanks for the help guys!

[Guest jumbojock]

Your PFD modes and MCP switching appears OK.But apart from being 20 kts below your Flap 10 speed, isn't your altimeter under-reading by at least 480 feet? I'm at the limit of my knowledge here, but I believe if you press B it will update the captain's altimeter with the QNH in use. Whilst your Radalt is indicating 180 ft, it looks like the yellow ground indicator is 300 ft above your present altitude. "We all live in a yellow submarine..." ####, I'm showing my age. Another suggestion is that there might be a mismatch between the AIRAC cycle you're using and the FS database - really not sure of that one, though.David "jumbojock" Robertson

[Guest Takechan]

Ah i've only calibrated it manually with the bug before takeoff to the dep airport, but forgot you could update it in flight - I take it that's what it does when you press B?- Takenobu Tou

[Guest jumbojock]

Yes or do it the real way by using the BARO knob on the EFIS control panel. Hope all your landings are smooth 1500 ft down the runway now.David "jumbojock" Robertson

[Guest Takechan]

Ah yes, thanks a lot for your help!I just want to thank everyone else who replied too!

[Tabs 2,790]

If you want to get a bit more advanced and realistic, try loading the actual ILS approaches into the FMC DEP/ARR page instead of just inserting a single fix along the runway centerline. Most major airports will have all the approaches in the FMC and you can follow the exact marker waypoints that real pilots would etc...

[downscc 1,327]

Piggybacking Ryan's suggestion, instead of selecting a runway for landing, you selected an ILS on the DEP/ARR screen, and most approaches have one or more transitions. This way, you can fly the approach from the initial approach fix (IAF), which is what's required real world unless you're vectored to final approach course by ATC. Approaches start at the IAF, and GS intercept is generally the final approach fix (FAF) - by which time you will already be close to landing configuration.Edit: Took another look, I notice you only have 10 flaps. You should be in final landing configuration before you descend below 1000 agl (above ground level)... and I notice your packs are off?

[craig_read 43]

Yes the above post is correct, this is not the correct procedure at all... I think really you'd benefit from a detailed description of the landing process.. If you've got this far it would be worth going the extra mile and learning about the STARs etc.. These are the approaches stored within the FMC.I also notice that your MCP set altitude is 00000, it should really be your missed approach altitude at this point.. The EGLL to LAX tutorial approach and landing section would be worth you reading. It covers a hold, approach and autoland landing in some detail into Los Angeles, this is found in the PMDG OPs pages. Take a look at that, have a read and see how you get on afterwards.CheersCraig