737 Go-Around question
 

If you press one of the TO/GA buttons within the criteria for engagement of go-around mode during a singe-channel ILS approach when you are still above the missed approach altitude, as set in the altitude window on the MCP - what would happen? I have searched through FCOM and FCTM without finding any satisfactory answers. I know what I would do if I end up in a situation like that, but I'm interested in a technical perspective.

Best regards

Exactly the same as with the normal go-around, except that the AFDS will stay in TO/GA mode until you change the pitch mode yourself or reset the MCP altitude to something above your current altitude. In simple terms, the aircraft will climb until it reaches it's performance-limited altitude.

Why should one dial in a M/A altitude in the MCP if above?

Look at LEMG/AGP charts for runway 13: MISAP 2000' but platform 12nm at 4200'

I know.
Oor SOP was (retired) to set 2.000 ft, or whatever G/A altitude, when below.

This is why you brief on how you will perform the go around. Simple way of doing it.

1. Press CWS (this will take it out of APP mode)

2. LVL CHG

3. CMD A/B

This keeps the aircraft in an automatic mode and you wont need to rush when doing it.

True, and I support the concept; but that's no reason not to be able to also do it by use of autopilot (with the weird sequence of commands in the edge case thought through ahead of time rather than during an actual goaround)

If you want to do it simply. Why not just deselect the ILS frequency then re-select it. That will put you in raw modes. You can then select LNAV and V/S. Far smoother than LVL CHG which is a crude thing when you're near the ground. You've probably got some power on and don't want to drop onto the MA platform like a stone do you?

For a descent I would agree with you. For a climb, I would use my method. I have used it both in the sim and on the line with no problems.

On 777 it will go into an unrestricted climb, 737 and 777 are pretty similar.

Easiest way is if your given a missed approach, before you press TOGA check the altitude selected. The is very rarely a rush to do a go around. If your above the missed approach altitude (on 777 anyway) so long as your above 1500ft if you deselect approach it will default to V/S and decent to and capture the missed approach altitude. When its level then select TOGA and follow the normal procedure.

737 does not allow you to deselect APP, hence deselecting ILS is better option, forcing APP to be dropped.
BTW: only selected autopilot needs deselecting, eg NAV 2 with CMD B

So you are saying you allow it to capture the missed approach altitude, then select TOGA? I'd say that's a bit dramatic.. Why not just wind a bit of speed on and clean up smoothly?

It sequences the checks and systems but does nothing else.

Because the question was what would happen if you were above it. Not particularly tidy if you were given a missed above the maa then decided to continue down below it before you decided to do the missed (a hundred feet above maybe) but just pushing the app button makes life easy.

In Stockholm you capture the G/S at 4000 ft and MAA is 1500 ft.

Because you might be asked to go around in the example at Stockholm above at say 3000 ft. Why would you descend below the 1500ft missed approach altitude? There is no need to, you would just ensure 1500ft was set and disengage the app mode. Job done.

In a climb when ATC tell you to climb 350 and your at 330 do you go through 350 and then descend back to 350?? Would make no sense would it. ATC might have words to say as well.

1, you’ve already been told that you cannot just disengage approach mode in the 737..... but you have a method where in effect you have the same by deselecting the ILS and placing the aircraft into an attitude stabilised mode. and letting the aircraft smoothly capture the MAA.
2, if you go around above a lower MAA then you’ll be descending anyway...... your descending slightly in a g/a (50ft or so if that), in the example above it was talking about more than slight a decent. A go around from way above the MAA and then descending hundreds of feet only to pass through through it, disconnecting the AP, large increase in thrust, cancelling any oral warnings, to climb back up, level off, re-engage AP etc etc doesn't make sense to me.
3, I’m sure ATC won’t mind if I descend to 1499’ before I go around to 1500’, would they?...... your going to push the GA at 1499....impressive, then next time when you miss by 2 feet and you press it at 1501ft and you go to an unrestricted climb they might mind, and before you say you will do it slightly lower than that....how much slightly? Is there an SOP in company X that says push g/a at x number of feet below ? I would be surprised. Then there is the A/P disconnecting in the 737 because of the G/A and the large increase in thrust etc etc, why? You can do it much more efficiently and much more smoothly.

As for the stupid comment.... its the same thing, I was using that argument as a hyperbole. You don't bust levels for the sake of it. That would be stupid.

How do you cope when ATC surprises you and sends you around just below, at or slightly above MAA?........ The operative words there are just above or just below. Then you deal with it as you describe. This discussion was about when you have plenty of time.

I made it up? :D:D And no its not a 'level bust' because its less than 300ft. Not great handling though is it. Do it any way you want, I don't really care :)

Perhaps with a platform altitude of 3000 and a missed approach altitude of 2000 for example
In Stockholm you capture the G/S at 4000 ft and MAA is 1500 ft.
Because you might be asked to go around in the example at Stockholm above at say 3000 ft.

​​​​​​Yup, all made up:rolleyes:. We don't always go around at exactly the minima or at the MAA in the examples above. Usually in a descending go around it ATC directed and in the above examples there is a long way between 3000 and 2000 in the first point say 1min approx that example, or 4000 and 1500 in second say 2 mins approx. I would say thats 'plenty of time'. If your unable to manage to get the aircraft to smoothly intercept a given altitude and level off in that period without going through selecting TOGA etc etc then you have more problems to worry about. As I said above:

How do you cope when ATC surprises you and sends you around just below, at or slightly above MAA?........ The operative words there are just above or just below. Then you deal with it as you describe. This discussion was about when you have plenty of time.

Ad hominem per chance?.:rolleyes:

It doesn't have to be an attack on character it is an attack on the individual as opposed to the argument. As for straw man, maybe you should read the previous posts a bit closer. PS And I don't really care how YOU fly your approach . Good luck next PPC

I never misrepresented your position at all, I, in fact agreed with your GA from close to the MAA, but you appear to be unable to see that there are more sides than your one to this problem.

Insulting me just proves your ignorance...QED ad hominem.