Go-Around procedure

[Captain_Al 66]

 

 

Incidentally, strictly speaking the sequence should be to press FLCH then SPD (the press of the SPD button will not normally have any effect -- it is just in case the aircraft has captured the missed approach altitude whilst still in TOGA which will result in the speed running away) but this should not have any impact on what you are seeing.
0

 

Just for your knowledge, this is not correct. If you push TO/GA to go-around, and you have a low altitude level off and you capture before your acceleration height, at your acceleration height when you push FLCH and bug up to your maneuvering speed or select VNAV, the pitch will change to FLCH SPD or VNAV SPD, the A/T will go to THR or THR REF and when capture occurs again depending on rate, the pitch mode will change to ALT or VNAV ALT, and the A/T will change to SPD automatically. There is no need to push FLCH, then the SPD button. In fact, the SPD button is inhibited anytime you are in VNAV or FLCH on the 400.

 

Now if you capture prior to the acceleration height and you do not select a pitch mode at the acceleration height (improper G/A procedure), that is when you have a problem because you will have THR | LNAV | ALT and no speed control when leveling off, that is when you need to either push the SPD button, or disconnect the A/T and pull the thrust levers back to control speed.

[skelsey 765]

Just for your knowledge, this is not correct. If you push TO/GA to go-around, and you have a low altitude level off and you capture before your acceleration height, at your acceleration height when you push FLCH and bug up to your maneuvering speed or select VNAV, the pitch will change to FLCH SPD or VNAV SPD, the A/T will go to THR or THR REF and when capture occurs again depending on rate, the pitch mode will change to ALT or VNAV ALT, and the A/T will change to SPD automatically. There is no need to push FLCH, then the SPD button. In fact, the SPD button is inhibited anytime you are in VNAV or FLCH on the 400.

 

Now if you capture prior to the acceleration height and you do not select a pitch mode at the acceleration height (improper G/A procedure), that is when you have a problem because you will have THR | LNAV | ALT and no speed control when leveling off, that is when you need to either push the SPD button, or disconnect the A/T and pull the thrust levers back to control speed.

 

I agree -- that is exactly what I said, and exactly why the Big Airline's B747 missed approach procedure used to be to press FLCH then SPD at Aa. Incidentally, it has now changed and the procedure is to remain in TOGA pitch all the way to misssed approach altitude rather than FLCH SPD at Aa:

At missed approach altitude, select FLCH or VNAV.

If FLCH is selected, press SPD and set speed to the maneuvering speed for the planned flap setting.

If VNAV is selected:

• select speed intervention as needed

• set speed to the maneuvering speed for the planned flap setting

Erm.. No !

 

On FLCH the thrust limit will switch to either CLB (all engines operating) or CON (engine out).

Errm... no .

 

Refer FCOM 4.10.7:

Flight Level Change (FLCH) Switch

Push –

• selects FLCH SPD pitch mode

• FLCH SPD pitch mode displays in green (active) on PFD flight mode annunciator

• when IAS/MACH window blank, IAS/MACH window opens to FMC target speed, if valid. If not valid, IAS/MACH window opens to current speed

• when IAS/MACH window open, displays command speed

• when changing from TO/GA to FLCH, IAS/MACH window displays highest value of current airspeed or selected speed

• AFDS pitch holds selected speed. When selected altitude captured, pitch flight mode annunciator changes to ALT

• A/T operates in THR, followed by HOLD mode in descent. When selected altitude captured, A/T mode changes to SPD. A/T advances or retards thrust levers to maintain a vertical speed proportional to the altitude change requested

• with higher altitude set in the ALT window, reference thrust limit changes to CLB when CRZ displayed and to CON with an engine inoperative

Note the critical bit I have highlighted in red .

 

I quite agree that FLCH does not necessarily drive the thrust levers to the thrust reference limit, however.

[Captain_Al 66]

Erm.. No !

 

On FLCH the thrust limit will switch to either CLB (all engines operating) or CON (engine out).

 

FLCH does not necessarily drive the throttles to max available thrust. See why in post(s) above

 

Hate to disagree with you, but there are 2 situations here on the 400.

 

If you are using FLCH to climb from 4000 feet to 6000 feet, FLCH will attempt to get you there in 2 minutes. So, in this case it would be a climb of approximately 1000 feet per minute for a change of 2000 feet. I agree it will not go to the reference thrust. Not the max available thrust, the reference thrust limit.

 

On a G/A, at the acceleration height, if you use FLCH for the pitch mode, the reference thrust will stay as G/A and not change to CLB until you push the THR pushbutton. So, procedurally at 1000 feet, you would select FLCH, bug the speed to your desired maneuvering speed, retract the flaps on schedule, and then when at your planned maneuvering speed and configuration, select THR, and then check that you have CLB thrust as the reference.

with higher altitude set in the ALT window, reference thrust limit changes to CLB when CRZ displayed and to CON with an engine inoperative

 

Skelsey, this has nothing to do with a Missed Approach...

Or Emvaos, sorry skelsy...

[skelsey 765]

Skelsey, this has nothing to do with a Missed Approach...

 

Or Emvaos, sorry skelsy...

 

Erm... I'm confused.

 

I think we're having a heated agreement, but just to be clear: the section of FCOM I highlighted is the technical reference that backs up the behaviour that you and I both agree should occur: when FLCH is selected during a GA the reference thrust limit remains at GA.

 

It remains at GA because it only changes to CLB if it was in CRZ.

[skelsey 765]

Actually, we don't quite agree:

If you push TO/GA to go-around, and you have a low altitude level off and you capture before your acceleration height, at your acceleration height when you push FLCH and bug up to your maneuvering speed or select VNAV, the pitch will change to FLCH SPD or VNAV

 

No - if the aircraft captures the missed approach altitude before you press FLCH then FLCH will not work, however often you press it.

 

Hence FLCH then SPD to protect you from any possible embarrassment. 99% of the time you press FLCH when you are well below the missed approach altitude, all the modes sequence as you describe and the SPD push does nothing.

 

1% of the time you get in to ALT before you press FLCH for whatever reason. However if you press FLCH then SPD this time the FLCH press will do nothing but the SPD press most certainly will. If you are in the habit of always pressing FLCH then SPD then you are always covered and therefore will (should) never cock it up.

 

That's how the World's Favourite have been doing it for many years anyway.

[Captain_Al 66]

Simon, I am not heated at all, just call it a friendly debate. I am very calm. I think in your response to me that we agree that on a G/A when you push FLCH, the reference thrust stays in GA, and yes now I see what your point is with that technical reference and what your reasoning is. So, do we agree that in the video, the thrust reference should not have changed to CLB when Mr Leif pushed FLCH. I think we are both on the same page there. In other words, the PMDG model is not correct in that regard.

 

I disagree however with your thought that pushing FLCH will do nothing if you happened to capture the MCP altitude first because of a low altitude missed approach before you get to your acceleration height. So, let's say you go around, you push TO/GA, G/A Thrust, Flaps 20, positive rate, gear up. You are in LNAV or HDG SEL as per ATC and now at 800 feet you capture the 2000 feet in the MCP. At 1000 feet (ACC HT), you push FLCH and bug the speed up to 200, 250, or whatever desired. The jet will go into FLCH (THR, FLCH SPD) and if the climb rate is within capture criteria, will immediately come out and go to ALT, but more importantly, the A/T will go to SPD, which is what you want. You retract flaps on schedule, push THR to get CLB at your flap maneuver configuration and level off at the missed approach altitude.

 

I understand what you are saying about going to FLCH, then pushing SPD, but that is totally unnecessary if you are procedurally correct in doing a missed approach. Where pilots get hosed up is when they do not do a proper missed approach procedure and same scenario, but at 1000 feet, the pilot does not select a pitch mode (he goes brain dead) of VNAV or FLCH and just keeps trucking along. Now, he will will be in THR | LNAV | ALT leveling at the missed approach altitude and there goes the speed off to the races. Now, he needs to push SPD...

 

I can't tell you the number of times I have seen everything I described above since teaching as an instructor, check airmen, and checking on this airplane as an FAA Examiner since 1988. If guys can find a way to hose it up, they will and I more than likely have seen it. If they properly follow procedure, piece of cake. When you say the worlds favorite are doing it this way, who are you talking about? I can't count the number of airlines domestic and worldwide I have taught through the years, but no one ever suggested that as a procedure, and instructors would be debriefing you on it if you did that on a missed approach. That sounds like someones technique, not procedure. Boeing and all the airlines I have ever been associated with would not condone that technique.

[willywonka 36]

So, what would happen if you try this in PSX?

[skelsey 765]

Hi Al,

 

Simon, I am not heated at all, just call it a friendly debate.

 

Absolutely -- sorry, I was being facetious when I referred to our "heated agreement" -- as I say, I think we actually agree on most of this!

 

do we agree that in the video, the thrust reference should not have changed to CLB when Mr Leif pushed FLCH. I think we are both on the same page there. In other words, the PMDG model is not correct in that regard.

 

100%!

 

I disagree however with your thought that pushing FLCH will do nothing if you happened to capture the MCP altitude first because of a low altitude missed approach before you get to your acceleration height. So, let's say you go around, you push TO/GA, G/A Thrust, Flaps 20, positive rate, gear up. You are in LNAV or HDG SEL as per ATC and now at 800 feet you capture the 2000 feet in the MCP. At 1000 feet (ACC HT), you push FLCH and bug the speed up to 200, 250, or whatever desired. The jet will go into FLCH (THR, FLCH SPD) and if the climb rate is within capture criteria, will immediately come out and go to ALT, but more importantly, the A/T will go to SPD, which is what you want. You retract flaps on schedule, push THR to get CLB at your flap maneuver configuration and level off at the missed approach altitude.

 

I am perhaps not being precise enough in my language -- when I say "capture the missed approach altitude" I mean the aircraft goes in to ALT. Imagine a slightly lower GA altitude -- let's say 1400ft for arguments sake, from an airport of elevation ~100ft. You do your go around, you should press FLCH at 1100ft (1000 aal) but for whatever reason you're a bit slow, forget, whatever. The aircraft goes in to ALT as it captures 1400ft.

 

As soon as it goes from TOGA to ALT, FLCH will not work (and if you made it really entertaining by doing a double press of the TOGA switches I imagine you could still be climbing at quite an impressive rate in ALT). This is the trap which drilling people to always press FLCH then SPD seeks to avoid. I understand why it is unnecessary 99% of the time -- but equally I can't see any downsides to the SPD press (can you? I assume Boeing couldn't -- hence the FCOM quotes below), and if it traps the occasional cock-up then it is probably worth it.

 

When you say the worlds favorite are doing it this way, who are you talking about?

 

BA (who as a rule do tend to do some funny things, but this specific one does make a lot of sense to me). As I say, the current procedure actually calls for staying in TOGA all the way to missed approach altitude, with no acceleration at 1000ft aal, although the drill is still to press FLCH then SPD once level at the missed approach altitude. As I quoted from the FCOM earlier:

 

At missed approach altitude, select FLCH or VNAV.

If FLCH is selected, press SPD and set speed to the maneuvering speed for the planned flap setting.
If VNAV is selected:
• select speed intervention as needed
• set speed to the maneuvering speed for the planned flap setting

 

That's the current procedure. I've just done some digging in my hard drive and found a pre-update FCOM (can't put it in a quote box because the forum is complaining!):

 

At acceleration altitude select FLCH then SPD.

Set speed to the maneuvering speed for the planned flap setting.

 

That is in line with how at least one former 747 Training Captain from said airline has explained it to me as well -- FLCH, SPD, 190 (ish) kt. I'm having lunch with a former very senior 744 Training Standards Captain who may very well have actually written the manual in a week or so's time, so I'll have to ask his thoughts on the matter!

[Captain_Al 66]

Hi Simon:

 

OK, I totally understand your reasoning as you expressed it. That is a strange procedure, but there are airlines that will incorporate procedures like this usually because somewhere, somehow some scenario happened to them and then they try to pilot proof it. Another reason is they try to standardize the procedure among the different fleets, so transitioning from one jet to another is as standard as possible. I suspect it could be a combination of both with BA.

 

So if I understand correctly, BA will just stay in the go around, once ALT capture occurs, select VNAV or FLCH, push SPD and then accelerate and retract flaps. Doing it this way is kind of close to a 777/787 go around procedure with the exception that most airlines will bug up at 1000 feet, retract flaps, and then once at the planned maneuvering flaps, select FLCH or VNAV and check CLB thrust. No one I know of, with the exception of BA now, pushes the SPD button. But hey if that is their procedure and I am a BA pilot, that is what I do.

 

OK, now I totally see where you are coming from, I have never seen anyone do quite that, but I have seen airlines go out of their way to change procedures usually because one or a combination of the above reasons. See, friendly debate and now we come to a resolution. Good discussion Simon.

[adamant365 28]

Let's throw a tiny wrench in this...say I'm practicing touch and gos using full manual control, but am following ILS and FD guidance. Obviously, autobrakes are not armed nor are spoilers. What's the procedure after touching down? Is GA or GA+ (two presses) still available after touching down if I had been using manual throttle control? Does the same GA procedure apply if I've already put weight-on-wheels?

 

What if the FD is off during the approach but I'm following the raw ILS signal for guidance? Will the FD reengage upon pressing the TOGA switch to follow the missed approach?

[skelsey 765]

Hi Al,

 

 

Captain_Al, on 09 Feb 2017 - 2:15 PM, said:

That is a strange procedure, but there are airlines that will incorporate procedures like this usually because somewhere, somehow some scenario happened to them and then they try to pilot proof it. Another reason is they try to standardize the procedure among the different fleets, so transitioning from one jet to another is as standard as possible. I suspect it could be a combination of both with BA.

Absolutely (my favourite piece of BA cross-fleet standardisation is the "altimeter check" calls that take place at FL100 and FL200, but not FL300. Why? Because when they were introduced, BA was still flying the Viscount, which couldn't get to FL300, so for standardisation...).

 

 

Captain_Al, on 09 Feb 2017 - 2:15 PM, said:

So if I understand correctly, BA will just stay in the go around, once ALT capture occurs, select VNAV or FLCH, push SPD and then accelerate and retract flaps.

That's correct (actually the SPD press is not required if VNAV is used because, as you know, with VNAV you will always get SPD mode automatically regardless of which mode you were in before).

 

Good discussion indeed -- I had always assumed the FLCH then SPD was a Boeing standard procedure but it seems not! Always enjoyable to discuss such things.

 

 

adamant365, on 09 Feb 2017 - 4:39 PM, said:

Is GA or GA+ (two presses) still available after touching down if I had been using manual throttle control?

Nope.

 

TOGA is available down to 5ft RA. Below that you can press TOGA as much as you want but it will not do anything (ask Emirates :wink:).

 

Therefore if you are going to go around below 5ft RA you must give it an armful of thrust manually (but you really should be backing the TOGA press up like that anyway... because it would be very embarrassing to try and go around without any thrust). Once you are airborne and above 5R you can then press TOGA to get the FD modes sorted. Apart from that it's really all the same -- GA thrust, flap 20, rotate, positive climb gear up and away you go.

 

The hard limit is reverse selection -- once you have pulled the reversers you are committed to a full stop landing. It is very worthwhile thinking about this sort of scenario in advance and how you will handle it, and worth trying out a few scenarios (for example, in a 'real' GA after touchdown amongst the TOGA mode issue you may/will also have to overcome spoiler extension and/or autobrake engagement).

 

 

adamant365, on 09 Feb 2017 - 4:39 PM, said:

What if the FD is off during the approach but I'm following the raw ILS signal for guidance? Will the FD reengage upon pressing the TOGA switch to follow the missed approach?

It should do, yes. EDIT: remember you will only get TO/GA pitch and TO/GA roll -- you have to select a roll mode manually at or above 400R.

 

Pop quiz question on the GA theme: what about if you were planning to do a 3-engine autoland (so you have all three autopilots engaged). You're happily coming down the glidepath, but unfortunately ATC tell you to go around. What are the potential pitfalls?

[adamant365 28]

TOGA is available down to 5ft RA. Below that you can press TOGA as much as you want but it will not do anything (ask Emirates :wink:).

 

Therefore if you are going to go around below 5ft RA you must give it an armful of thrust manually (but you really should be backing the TOGA press up like that anyway... because it would be very embarrassing to try and go around without any thrust). Once you are airborne and above 5R you can then press TOGA to get the FD modes sorted. Apart from that it's really all the same -- GA thrust, flap 20, rotate, positive climb gear up and away you go.

 

So if I'm on the ground (obviously below 5' RA), and I instinctively press TOGA while manually increasing thrust, once I'm above 5' RA, will pressing TOGA then give tier 1 (2000 ft/min climb) or will it have registered my <5' RA as a "press" and therefore give full TOGA thrust?

 

So you're saying Boeing GA isn't like Airbus? :wink: I'll be honest, I've been simming for many many years and pretty much neglected practicing GAs until the FSL A320 came out. I "got" the whole Go-Around procedure after that.

[skelsey 765]

 

 

So if I'm on the ground (obviously below 5' RA), and I instinctively press TOGA while manually increasing thrust, once I'm above 5' RA, will pressing TOGA then give tier 1 (2000 ft/min climb) or will it have registered my <5' RA as a "press" and therefore give full TOGA thrust?

 

2000fpm -- the first <5R press won't be registered at all.

 

 

 

So you're saying Boeing GA isn't like Airbus? I'll be honest, I've been simming for many many years and pretty much neglected practicing GAs until the FSL A320 came out. I "got" the whole Go-Around procedure after that.

 

. I think in all honesty this is one area where Airbus have got it pretty well nailed over Boeing -- if you want to go around, just shove the thrust levers to the forward stops. Works in all situations!

[adamant365 28]

Excellent replies Simon, thank you! And a great discussion too. It makes me understand the reason why that EK flight got into trouble. Not that it's an excuse for poor airmanship (back up the throttles with your hands when changing modes!!), but I can see being "confused" at the wrong time.

[Captain_Al 66]

 

 

Absolutely (my favourite piece of BA cross-fleet standardisation is the "altimeter check" calls that take place at FL100 and FL200, but not FL300. Why? Because when they were introduced, BA was still flying the Viscount, which couldn't get to FL300, so for standardisation...).

 

Yes, that is funny, that is a classic example...at Northwest Airlines when the 757 was introduced, for a good 2 to 3 years after it was put in service, during training Rapid Descents were always hand flown, A/P off. A/T off, FD's off. In a meeting, when I asked why we are doing it this way, the answer was because that is how we did it in the 727. Took a while, but they came around to using the Autopilot, with the option of hand flying it. Sometimes it is hard to change the airline culture.