A/THR on Approach

[NG_Aviator 39]

Hi GuysSorry if this seems to be a stupid question... I have been watching some videos and noticed that during the approach, the captain keeps his hands on the throttles before the autopilot is disconnected. Is it normal to manually operate the throttle with the autopilot engaged? When is the A/THR usually disconnected?Thanks!!!!

[ajpongress 467]

From what I understand it's common for commercial pilots to perform "coupled" approaches where autopilot and autothrottle are used until decision height (around 200 ft normally).At this point the captain uncouples the autopilots and lands the plane manually.If the pilot has his hand on the throttle I'm sure it's to take over immediately in case the autothrottle either fails or conditions on landing change rapidly requiring manual control (such as really strong crosswinds over the threshold that the autopilots can't react quickly enough to).The A/T cutoff switch is normally found on the throttle itself, so his hand is there as a reassurance and manual backup.

[NAVRAD 0]

It's your choice.Leaving the A/T engaged the throttles will return to idle at 50ft. You can of course disengage the A/T when you like and adjust the speed manually. Manually can be challenging but fun!!If I land manually I normally disengage the A/T and A/T at around 1000ft.Hope that helpsAlan W

[Andrea1 6]

Leaving the A/T engaged the throttles will return to idle at 50ft. You can of course disengage the A/T when you like and adjust the speed manually. Manually can be challenging but fun!!If I land manually I normally disengage the A/T and A/T at around 1000ft.It's not really true: when you are performing automatic approach (autoland) the throttles can be (and are) left engaged always but during manual flight it's explained in the Boeing 737 manuals (i.e. I got the CAL B737 FCOM) it's not designed to cope with manual landings (like i.e. the Md80 where you can mantain it engaged during a manual landing and teorically you could also, after an engine failure, after having sthutoff the failed engine and re-aligned the throttle reengage it) so it's always requested to disengage it during a manual landing not necessarly ast 1000 ft AGL because that it's usually a standard operating procedure of any company (or of any pilot) some company i.e. (if air is not rough) request to mantain engaged it until reaching the minima (and autopilot too) to save a little fuel...)CiaoAndrea B.

[NAVRAD 0]

Sorry to disagree with what you say but (and you may be a pilot) but I have pilots who fly my sim and fly this way!!Ultimately it's not unsafe and is simulated in FS so can't be that wrong.RegardsAlan W

[ronzie 21]

During take-off and landing procedures before or after a specified AGL either the PF (Pilot Flying) or PNF (Pilot Not Flying) would have a hand always resting on the throttle controls but not inhibiting A/T movement as a safety precaution. The AGL threshold height is specified usually by airline practice.At b737.org.uk in one of the procedure Power Point presentations regarding old/new procedure changes it states for take-off the Captain will keep his hands in the thrust levers until V1. I didn't catch anything about landing.In addition there is a comment about the PF keeping his hands on the thrust levers during strong headwinds in landing.

[Spin737 102]

So many opinions!Many airlines have an altitude below which you "guard" the controls, (eg. Below 10,000'). You're hands are there to take over in case the plane isn't doing what it's supposed to be doing. If you are doing an auto-land, the A/P and A/T stay on the entire way to touchdown.

[fencer 16]

From what I understand it's common for commercial pilots to perform "coupled" approaches where autopilot and autothrottle are used until decision height (around 200 ft normally).At this point the captain uncouples the autopilots and lands the plane manually.

Hi,I am not sure I agree with this (but I am NOT a commercial pilot...)For me, decision height (or altitude) is not the point where you switch from automatic (ie AP and ATHR) to manual but, as you probably know full well, the point when you decide to either continue the landing or go around.Having been told of the importance of a stabilized approach, I don't see the case for switching from auto to manual at such a late stage. In other words, I would imagine the PF would not want to change ANYTHING in the plane configuration at such a low altitude. All he/she does is fly the airplane to either land or go around. So I would imagine, eventual switching from auto to manual would take place at a higher altitude/height.Am I wrong on this one?Bruno

[Spin737 102]

Hi,I am not sure I agree with this (but I am NOT a commercial pilot...)For me, decision height (or altitude) is not the point where you switch from automatic (ie AP and ATHR) to manual but, as you probably know full well, the point when you decide to either continue the landing or go around.Having been told of the importance of a stabilized approach, I don't see the case for switching from auto to manual at such a late stage. In other words, I would imagine the PF would not want to change ANYTHING in the plane configuration at such a low altitude. All he/she does is fly the airplane to either land or go around. So I would imagine, eventual switching from auto to manual would take place at a higher altitude/height.Am I wrong on this one?Bruno

A stabilized approach is very important, but switching to manual flight isn't really changing the configuration. For the 737, the A/P needs to be off at 50' AGL for a Single-Channel ILS. I'd probably have the A/P off as soon as I had the runway in sight, whenever that is. If you're doing a Dual-Channel ILS, but you plan to land manually, it's probably best to disconnect before 400' since the plane "pre-trims" for the flare/go-around at 400'. Some airlines actually have some sim time devoted to manual flight after that trim. I've never done it. If it's not "hard IFR" (ie close to minimums), I'll probably disconnect the A/P around 1,500'AGL. As an aside, per Boeing, A/T is off on when A/P is off on approach.