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rgamurot

A/T Procedures During Landing

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I always see in checklists that the autothrottle is shut off during taxi in. I also can't find any information in the manual on this. My problem is that during approach, the A/T doesn't give me control of the engines. I decided to let the A/T control the engines during final into EGLL once but when I went to flare, the aircraft wouldn't slow or decend. (I decided to risk it and cut the A/T then touched down little more than half way down the rwy. Really wouldn't recommend this to anyone.)Other than that, if I do manage to gain control of the engines by pressing random buttons on the MCP till I win, sometimes the engines will go to full thrust and lock me out anyway. Unless I fly an automatic approach, I disarm the A/T with the A/P. What should I really be doing with the A/T?Ryan GamurotLucky to live Hawai'ihttp://www.precisionmanuals.com/images/forum/supporter.jpg


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Ryan Gamurot
 

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Guest balt

I was having the same problem today, first time. I was playing around with the FMC, practising different approaches etc. Did you have your speed brakes armed?At some point during the last approach, I had a number of problems which resulted in the A/P giving me command over the speed bug, instead of VNAV taking care of it all. I set the speed at Vref+10, had LAND3 announced and all the goodies, but no speed brake armed (forgot, fighting FPLN DISCONTINUITY messages, impressively illustrating the fly-navigate-operate principle).*I think* this was due to me not arming the speed brakes. I did touch down, but A/T kept the speed at Vref+10.Cheers- Balt

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I always arm my speed brakes as soon as I start my decent so I don't have to worry about it later. I'll admit that's a bit early in the approach and sometimes if I need it to slow down the aircraft during decent, it gets tricky. But yeah, I always make sure it's armed before my final.Ryan GamurotLucky to live Hawai'ihttp://www.precisionmanuals.com/images/forum/supporter.jpg


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Ryan Gamurot
 

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Guest Hawkeyeted

Ryan said: "...if I do manage to gain control of the engines by pressing random buttons on the MCP till I win, sometimes the engines will go to full thrust and lock me out anyway. Unless I fly an automatic approach, I disarm the A/T with the A/P. What should I really be doing with the A/T?"I think Ryan is refering to a standard CAT I ILS approach. If that is the case, standard practice is to hit the A/P disconnect bar AND disarm the A/T switch at 200 ft AGL (the standard MDA for a CAT I ILS). That will give you manual control to land as you see fit.However, it sounds like Balt is describing a CAT III Autoland, ("I had a number of problems which resulted in the A/P giving me command over the speed bug, instead of VNAV taking care of it all. I set the speed at Vref+10, had LAND3 announced..."). You shouldn't have to touch a thing on the MCP until after the rollout, in which you can hit the A/P disconnect bar and A/T switch. Additionally, VNAV is NOT...repeat NOT...a precision landing tool. It is useful for planning cruise descents and non-precision approaches. Beyond that, you'll be asking a bit too much of the autopilot.I recommend you both read PMDG's "Autothrottle Care and Feeding". it should explain all your questions on what the autothrottle can and can't do. The course located here:http://ops.precisionmanuals.com/wiki/PMDG_...are_and_Feeding

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Actually I was talking about a manual approach from about 8 miles out. I only fly an automatic approach during poor visibility. Does this mean I should disarm the A/T with the autopilot when I switch to manual?Thanks for the help, Ted.Ryan GamurotLucky to live Hawai'ihttp://www.precisionmanuals.com/images/forum/supporter.jpg


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Guest Hawkeyeted

Ryan,Here is what I recommend:For a non-precision approach (i.e. anything other than an ILS), when inside the Final Approach Fix (which is usually within the neighborhood of 8 miles as you suggested), set the MCP SPD mode to the the Flaps 30 schedule as calculated in the FMC Approach page, use the V/S to control the descent angle (should never have to deviate more than +/- 300 fpm), and use the LNAV mode to track and maintain a reasonable runway line up. When you're 50 ft above the Missed Approach Point and can see the "runway environment" (there is no hard definition of this, so if you feel you can safely land the aircraft with visual cues on the ground, thats your "environment"), disconnect everything and land manually.If its a precision approach (CAT I or II) I simply set the aircraft up with the same settings, but let the ILS receivers take me down to the MDA, at which point I disconnect everything an land manually. Keep in mind that on the 747-400 and CAT II ILS requires Autoland. (I suspect it's because it is possible for the cockpit still be in the soup simply because the cockpit is so high at the threshold crossing.)For a CAT III approach, I set the aircraft up in the same manner, continually monitor airspeed, altitude and line-up for deviations, and watch for the "LAND3", "FLARE" and "ROLLOUT" arming to occur. When at the AH+50 I give a quick look out the front for the "runway environment". If it's not there, I continue to watch the instruments until touchdown.You'll find that the hardest part of a CAT III landing is taxiing after the landing. It's hard to navigate on the ground when you can't see it!

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Thanks so much for the help.>You'll find that the hardest part of a CAT III landing is>taxiing after the landing. It's hard to navigate on the>ground when you can't see it!I landed at London Heathrow during the heavy fog. I know what you mean!Happy New Years!Ryan GamurotLucky to live Hawai'ihttp://www.precisionmanuals.com/images/forum/supporter.jpg


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Simple answer...The 744 (real or PMDG) will not idle the throttles during flare if Autoland is NOT engaged for landing. The A/T will remain in speed mode if you forget to disconnect the A/T before flare.Rgds.Q>

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I didn't realise that the A/T didn't give control back until now. I thought you were supposed to leave it armed incase you wanted/needed to perform a go around. That and all the checklist and procedures I saw said to disarm it during taxi in. Now I know to disconnect the A/T once I go manual.But this actually brings up a good question. Without autothrottle, how do I perform a go around? Just trottle up and climb out manually?Ryan GamurotLucky to live Hawai'ihttp://www.precisionmanuals.com/images/forum/supporter.jpg


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Don't confuse disconnect with dis-ARM, Ryan.Our flight crews don't dis-ARM the A/T even after parking at the gate. G/A is still available if you don't dis-ARM. To disconnect, just hit the A/T disconnect switches on the throttles (or programme a joystick button to do this.Hope this makes sense.Cheers.Q>

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Guest fyrestrtr

"It's hard to navigate on the ground when you can't see it!"I wonder how 747 pilots do this in real life when they land in thick fog. Is there some system in place that tells them where are the turns or when to begin turning?I have trouble just lining up on the centerline in relatively clear weather (I cheat by using the top down view).

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I've noticed that at many airports, there are lights in the centre line. In FS, it's those green lights between the blue ones and it's probably the same in tne real-world. I beleve that this is how they find their way. Then again, I'm not sure how they see the taxiway signs. Aside from following their charts very closely, I'm sure they have other ways to make up for this.Ryan GamurotLucky to live Hawai'ihttp://www.precisionmanuals.com/images/forum/supporter.jpg


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Guest fyrestrtr

Maybe those outbound cameras? I know of the lights that you are talking about, but if the aircraft is landing under CATIII conditions, or deep soup, then from the cockpit of a 747, I don't think its possible to see them.Curious as to how they do it; as I'm sure the tower can't provide them directions.

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Guest BAW1085

I'm slightly confused what A/T disconnect command ? It doesn't exist in PMDG or FS key commands as far as I can see. Nor have I seen the A/T disconnect switches modelled on the PMDG throttle ??For ILS CatIII when I see the Speed Mode go to IDLE I flick off the Arm A/T switch on the glare shield (which effectively disconnects it), . Then switch it back on again to re-arm prior to TD. Although frankly this would only give me A/T GA after touching down...A tad late methinks.Thrust reverse will also Dis-Arm, Or is it disconnect the A/T ... ???David MilesAirbus

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