Lionair plane down in Bali.

[Old King Coal]

aa73:

On AA's 738s when you hit TOGA, the A/P disconnects (if it were previously engaged.) All GAs are hand-flown initially... but we can re-engage the A/P above 500'. Not sure if this is the case for all 738s.

Yes, that is the case on all B737's (Classic's & NG's) but there's a bit more to it than that… and there's a gotcha in what you suggest about re-engaging the autopilot.

Fwiw, here's how I teach and brief a two-engine go-around in a B737.

Nb. I'm a lot less interested in the lateral part of a go-around, than I am in the vertical part of the go-around, i.e. the main point of a go-around being to go back up into the air... much on the basis that nobody has ever collided with the air !

With a single autopilot engaged (i.e. 'single channel'), if you press the go-around button, the autopilot will disconnect. It is then up to you to push up the thrust levers and manage the pitch-up of the nose.

Nb. Some on here might be using the 'Speed Off' method during the approach phase which, I seem to recall, allows the auto throttle to remain engaged during the go-around, though you shouldn't rely on it to work, i.e. always advance the thrust levers yourself!

When the TOGA button is pressed, the MCP speed window will blank and it will remain blanked until you either press something (to do with power or pitch, or select an autopilot) on the MCP or that you get 'Altitude Acquire' (which ever happens first), at which point the MCP speed window will then open up at the speed that you are doing at that precise moment (which is not necessarily the speed that you were previously accelerating towards, i.e. prior to the speed window opening).

Here's a handy little reminder for managing the vital actions of a go-around: "Say. Do. See."

1) Say = "Go Around, Flap 15"
2) Do = Click TOGA button; Advance the thrust levers; Raise the nose!
3) See = TOGA on your FMA and also G/A on the thrust mode annunciation.

Nb. If you do not see 3) then you didn't press the TOGA button, doh!… and then the following will happen:

• If you remembered to advance the thrust levers, the aircraft is probably now pitching-up / climbing.
• The flight directors are still providing guidance for the last selected approach mode (i.e. probably commanding a descent).
• The flap lever position based acceleration function will not work as advertised for a B737 doing a two-engine go-around.

Therein, "Say. Do. See." will at least get you going up, and in TOGA mode, and hopefully also get you into the mindset for the go-around.

@400 ft AGL - choose an appropriate roll mode (LNAV or HDG).

When at or above your airlines nominated Acceleration Altitude, AND so long as your aircraft is at or faster than Vref +15kts (i.e. at or above the white bug on your speed tape), ask for "Flap 5"… and then keep on raising the flaps in accordance with the increasing airspeed and note that, as you raise the flaps, the ASI bug will keep advancing to the speed for the next flap position.

If there's a long way to climb to your missed approach altitude then it's likely that you'll have flaps-up by the point when you get 'Altitude Acquire', whereupon the MCP speed window will open up at the speed that you are at, which (if you've been following your flight director) will be the flaps-up speed.

Alternatively, once the flaps are up (and prior to getting 'Altitude Acquire'), you can select any MCP power or pitch mode that you desire (e.g. LVL CHG, VNAV, V/S,... or an autopilot) without it screwing-up your TOGA mode thrust & acceleration.

If however, when you get 'Altitude Acquire', you are still at some intermediate flap setting, then the MCP speed window will open up (at the speed that you are at) and it's then up to you to drive MCP speed bug.

Also, if prior to getting your flaps fully up, you decide the press something on the MCP to do with either power or pitch (or select an autopilot), you will then cause the TOGA mode to cancel. The MCP speed window will open up (at the speed that you are at) and it's then up to you to drive MCP speed bug.

In my experience, the typical things that people select on the MCP during a go-around are any combination of autopilot & auto-throttle but, by doing so, they then take the aircraft out of TOGA mode and which, aside from screwing-up the flap lever position based acceleration (which Boeing have kindly provided), it also commands your thrust into another mode (of a thrust reduction; which might be ok, just so long as obstacles in the missed approach path are not an issue?!).

737-Classic's: the TOGA mode is available any time the aircraft registers that it is at or below 2,000 ft radio altitude.
737-NG's: the TOGA mode is available any time the flaps are not up (regardless of altitude) and / or (if flaps are up) any time the aircraft registers that it is at or below 2,000 ft radio altitude, or with the GlideSlope captured.

Simples!