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When to disconnect auto throttle before landing

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Hello In the real world does the auto throttle get disconnected when the autopilot is disconnected or do pilots let AT control the approach speed all the way down, also does lnav and vnav only work once the auto pilot is turned on after takeoff, thanks Wayne

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Some airlines do not allow their crews to have the autothrottle on while the autopilot is off during approach. I follow this policy and just disconnect both of them at the same time.

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Some airlines do not allow their crews to have the autothrottle on while the autopilot is off during approach. I follow this policy and just disconnect both of them at the same time.
I do the same. I'm not sure what FAA policies exist regarding this, but from a purely systems stand point it just needs to be disconnected in time to retard the throttles to idle. If you're performing an autoland, even this will be automatic (but where's the fun in that). Eric Szczesniak

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After disconnecting AP the AT is running and will deactivating when you turn it off. Before take-off, you can set the AT on and select the LNAV and VNAV on, the AP can select above 400ft take off.

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I disconnect at around 100ft. Some real world pilots hand fly down and would like to control the throttles as well, but in FS I find it hard not to over power or under power, so I let the AT stay in place until just over the threshold.

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Remember that power affects your pitch. If the auto-throttle is on, you will tend to overpitch: as you raise the nose, the A/T will increase power to compensate for loss of speed. This extra power will raise your noise further. The opposite applies for lowering the nose. For this reason, many pilots tend to disconnect the auto-throttle when they disconnect the autopilot. If you don't do this, the autothrottle will reduce to idle at 27 feet radio altimeter and then disconnect two seconds after touchdown.

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Hello In the real world does the auto throttle get disconnected when the autopilot is disconnected or do pilots let AT control the approach speed all the way down, also does lnav and vnav only work once the auto pilot is turned on after takeoff, thanks Wayne
A search in this forum will show multiple posts by rw 737 pilots stating that Boeing's officiel policy (or recommendation) is to turn off AT when AP is off. Bruno

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Remember that power affects your pitch. If the auto-throttle is on, you will tend to overpitch: as you raise the nose, the A/T will increase power to compensate for loss of speed. This extra power will raise your noise further. The opposite applies for lowering the nose. For this reason, many pilots tend to disconnect the auto-throttle when they disconnect the autopilot. If you don't do this, the autothrottle will reduce to idle at 27 feet radio altimeter and then disconnect two seconds after touchdown.
Wow I had no idea it idles and then disconnects after touchdown, another awesome feature I didnt even know about.

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While there is no official FAA stance on the use of A/T, there is an official stance on the use of A/P for commercial operations: FAR 121.579: 500' or twice the AP fail altitude loss specified by the aircraft's AFM, whichever is lower (providing exceptions for specific operations).

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A/T and A/P off at about 1000 feet and hand fly the rest. I understood it was Boeing policy that A/T should be off when A/P is off. I recall I read that in the manuals.

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As I have been struggling to manage power on landing when flying without A/P, I have been looking for info on using A/T without A/P. Reading this topic here, it appeared to me that indeed A/T should not be used if A/P is disconnected.I have just been watching a "Cockpit video" featuring the 737-600 flown by Westjet, with a landing visual landing in Fort McMurray. Interesting enough, the PIC flew the aircraft manually but left A/T on until flying over the runway threshold. I clearly heard the PIC order "A/T disconnect" just before touch down.Is there a Westjet pilot out there to comment on this (or anybody else) ? Thanks.

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As I have been struggling to manage power on landing when flying without A/P, I have been looking for info on using A/T without A/P. Reading this topic here, it appeared to me that indeed A/T should not be used if A/P is disconnected.I have just been watching a "Cockpit video" featuring the 737-600 flown by Westjet, with a landing visual landing in Fort McMurray. Interesting enough, the PIC flew the aircraft manually but left A/T on until flying over the runway threshold. I clearly heard the PIC order "A/T disconnect" just before touch down.Is there a Westjet pilot out there to comment on this (or anybody else) ? Thanks.
Any possibility you could post a link to that video?Regards,

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As I have been struggling to manage power on landing when flying without A/P, I have been looking for info on using A/T without A/P.
What problems are you having?

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Hello guys, I found this video: 

You can see the pilot disconnected the AP before the video, and discounted the A/T on about 130ft. "MCP SPD" gone at 1:38, and you can here a "click".   

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You can see the pilot disconnected the AP before the video, and discounted the A/T on about 130ft. "MCP SPD" gone at 1:38, and you can here a "click".   

 

Full names in the forum, please.

 

I always caution the use of real world flight videos from YouTube as a source of "actual" procedures. Procedures vary greatly from operator to operator.

 

The answer for when to turn off the AP or AT is simply: when you're ready to assume control of the aircraft (provided it is above the minimum altitudes specified for AP use).

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Exactly, operators vary.  At one time, and it may still be true, SWA pilots did not use A/T on approach.  Hands on throttles does keep you in the loop.

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At one time, and it may still be true, SWA pilots did not use A/T on approach.

 

If I remember correctly, they didn't use it at all for quite some time. Same with VNAV.

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There was a big thread about this years ago. If I remember it seems that a lot of airliners like the pilots to turn off AT on approach.

 

I always turn AT off  on GS capture then AP off once am at flaps 30/40(unless vis is low),My landing have always been better with AT off as VAPP can often be more than +5 and I can judge when to be a retard :P  

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downscc, on 23 Apr 2015 - 09:44 AM, said:

At one time, and it may still be true, SWA pilots did not use A/T on approach.

 

If I remember correctly, they didn't use it at all for quite some time. Same with VNAV.

 

 

 

I think they still turn it off at the same appx time they turn off the A/P, but being I don't work

there, not 100% positive.. They didn't use A/T or VNAV until around the switch to RNP.

Where the VNAV button was usually had a metal cover over it instead. For a good while

they didn't use auto brakes either, but started using those a few years back a good bit

before the switch to RNP. 

Myself, I prefer the A/T off when landing, and usually turn it off when I turn off the A/P,

which is usually about the time I drop the gear and go to flaps 15, or shortly after.

I also prefer judging for myself when to be a retard..  :lol:

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Who is we?

 

For what it's worth, people in aviation rarely disclose who they work for when they're currently working for them. I got quite a rude awakening when I worked for a contractor providing ground services to United Express ops at IAD. I'd posted an incredibly sarcastic (and, in my own mind, very obviously tongue-in-cheek) apologetic post on a real world aviation forum I frequented. I'd intimated that the handler was apologetic at the terrible level of service due to under-staffing and lack of workable equipment. While both were true, the company came unglued. Wasn't the brightest move on my part, but even less objectionable actions have been met with negative action from employers because their name was mentioned in the post.

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I just disconnect when I am a thousand above and hand fly it in the rest of the way with Auto-Throttle on until the plane is down on the ground and slowed to 30 knots and turning off the runway.   I've watched a ton of real world documentary and it just varies.   I use to just sit back and let autoland have all the fun while I sipped on a a martini but now the 737 no longer intimidates me.   We're best friends.

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