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In Wikipedia's description of one of air crashes (probably Thai Airlines, if I recall correctly), I found a remark saying something like that: "Crew decided to go-round, but apparently decided to undertake this procedure manually".

I'm surprised. "Apparently"? Making go-round manually is something odd? Do we have any automated (auto-pilot-based) go-round procedures or techniques in common use? I was always more than sure, that procedures like go-round or touch-and-go are always made manually by a pilots.

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Wikipedia says "On Airbus planes pushing throttles to TOGA detent [Take-Off/Go Around] does all regarding flight path and speed" –  RedGrittyBrick Aug 18 at 10:29
    
Just to clarify, all instrument approaches terminate at a hold after the missed approach segment. If you don't land and reconnect the autopilot, it will take you through the missed approach and enter the hold (assuming your autopilot is advanced enough) once you fly past the touchdown waypoint (or perhaps the missed approach point, I'm not all to familiar with automation details). –  falstro Aug 18 at 12:02

2 Answers 2

up vote 6 down vote accepted

For go-around, several things have to be done in the moment the decision is taken:

  • Apply full power (obviously),
  • disconnect autopilot glide-slope mode,
  • disarm spoilers and retract them if they are extended,
  • disarm autobrakes and
  • in some aircraft reduce flaps.

Modern airliners, and some smaller aircraft, have a method for doing all of these at once via the TO/GA button. On Airbus aircraft it is done by just advancing the thrust levers to the TO/GA (full power) position, but on Boeing aircraft and many other types it is a separate button on or near the thrust levers.

So if the crew "apparently decided to undertake this procedure manually" it means they moved the thrust levers forward and started changing the other things. And probably missed one of them.

Notes:

  • I am not sure whether lateral mode remains under automatic control or not and it probably depends on aircraft as some can connect autopilot to only roll or only pitch and others don't. Pitch control is manual immediately after go-around in either case.

  • The last flap setting usually adds a lot of drag and a little lift. In some types the drag is too large and the flaps have to be retracted to the last usable position. On other aircraft they can be used in any position and have to be left were they were to avoid loosing lift.

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Normally on a "go around" the pilot flies the airfield traffic pattern and attempts to land again, usually after a visual approach. This is done manually as far as I know. The "missed approach" which is a published instrument procedure, is described in the aircraft's FMS (for an FMS equipped aircraft) and can be activated by the crew and flown automatically.

Since I am not a professional this is as afar as I know. More details (about rules regulations e.t.c.) can be provided by others. But unless you provide more details about the accident, I think that little can be explained for the case.

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A "go around" on an instrument approach implies flying a missed approach, not a traffic pattern. –  falstro Aug 18 at 11:27
    
@falstro What happens when an instrument approach is terminated and becomes visual? Is it a go-around then or the published missed? But the real question for me is: Is there an automated way to perform go-around in terms of traffic pattern? Or it should be manually executed, even if that requires continuous autopilot input from the pilot? That's what I'm missing and frankly makes me think of withdrawing my answer... –  Stelios Adamantidis Aug 18 at 11:41
    
The go-around and the missed approach are two different things. The go-around itself is the process of terminating the landing attempt and configuring the airplane to position for another approach. The missed approach following an instrument arrival is a described lateral and vertical path, a set of instructions carried out to actually get back to the initial approach fix (IAF). The missed approach follows the go-around, but the terms really mean different things. Patterns are usually for VFR flights and not made after IFR approaches. –  SentryRaven Aug 18 at 11:52
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The visual part of an instrument approach is still an instrument approach, thus "going around" means you fly the missed approach for that instrument approach (it hasn't terminated, it's just on the visual segment of the approach). It's a little more blurry if you fly a visual approach (still IFR) as they don't have a published missed approach (AFAIK). If you cancel IFR and do a VFR approach, then of course you do the normal traffic pattern. As for the rest, all approaches terminate at the hold after the missed, the autopilot can probably take care of that once you make the decision not to land –  falstro Aug 18 at 11:53

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