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-   -   Use of FL LVL CH versus TOGA for a B737 go around (https://www.pprune.org/tech-log/563671-use-fl-lvl-ch-versus-toga-b737-go-around.html)

downwind 28th Jun 2015 02:04

Use of FL LVL CH versus TOGA for a B737 go around
 
Hello all,

Recently during simulator training one of our instructors is telling us that we DO not need to use TOGA when performing a go-around from say 1000 AGL?(Boeing 737 family I am talking about).

Let me further break down what his opinion was at level of around 1000 AGL it is more than sufficient to use LVL CHNG rather then TOGA since the missed approach altitude might only be be say 2000 or 3000 AGL (airmanship was the word he used)

Most of our airport operations are sea level aerodrome's, then he went on to say that around 200-300 AGL ie CAT 1 DA or MDA's etc... always use TOGA, since this is a break away manoeuvre to avoid the ground and initiate the missed approach ie; for weather, aircraft on runway or as the case may be.........

having read FCOM and FCTM they are say TOGA ONLY....

FCOM Normal Procedure's section.............

At the same time: • push the TO/GA switch • call “FLAPS 15.”

FCTM.....

Push either TO/GA switch, call for flaps 15, ensure go-around thrust for the nominal climb rate is set and monitor autopilot performance.

I also found in FCOM when APP is engaged ie VOR/LOC and G/S captured that it would take up to much pilot attention to use this technique of FL CHNG vs TOGA, tried this in the sim all to hard work...........

After VOR/LOC and G/S are both captured, the APP mode can be exited by:
• pushing a TO/GA switch
• disengaging A/P and turning off both F/D switches
• retuning a VHF NAV receiver.

What are people opinions of this technique?
I just went along with it in the sim to keep the piece but I find it a bit silly this idea....

Thank you in advance.

c100driver 28th Jun 2015 03:06

I agree with you, it is a silly idea.

Best report the instructor to your training department I am sure that they would have a very different opinion.

TOGA is TOGA!

InSoMnIaC 28th Jun 2015 03:37


After VOR/LOC and G/S are both captured, the APP mode can be exited by:
• pushing a TO/GA switch
• disengaging A/P and turning off both F/D switches
• retuning a VHF NAV receiver.
How then does he expect you to engage LvL chg at 1000' if loc and gs are captured.

Just do what boeing says and let him mark you down for it. This will make him look Silly. Not you. Btw i would adopt the procedure he is advocating if I discontinue the approach from higher up but at 1000' you are already established. Stick to the basics. Hit TOGA first and then lvl chg when appropriate (which maybe very shortly after)

casablanca 28th Jun 2015 04:14

The 777 may be different but the first push of toga initiates a climb of approximately 2000 per minute.....the second push will set full go-around thrust.
Many of the earlier models I flew only went to full thrust so it may cause a light airplane to overshoot a low altitude level off, so I understand what he is talking about, but as pointed out Toga is really the best way to get plane quickly out of approach mode.

ironbutt57 28th Jun 2015 04:57

selecting TOGA also places the FMC in the G/A mode....no need to REMAIN in G/A mode for an extended period, but it needs to be selected initially...

AerocatS2A 28th Jun 2015 06:48

Downwind, what technique would you use to do a "missed approach" from 2500' AGL? Still TOGA? What about 3500'?

FlyingStone 28th Jun 2015 07:19

The most common mistake is to think go-around at minimum and go-around at 1000ft involve exactly the same procedure.

At minimum, there is no question, you have to go TOGA and do the rest of the actions immediately, otherwise you'll bust the minimum. But at 1000ft if you are either unstabilised or ordered go-around from ATC, you can take a deep breath, verify missed approach altitude is set, review go-around procedure and do it slowly without any rush.

As far as the TOGA vs. LVL CHG goes, I'd always go with TOGA below 2000ft RA - the only exception being if I'm very close to missed approach altitude (e.g. go-around from 1800ft with missed approach altitude 2000ft). As said, this is the easiest way to get out of approach mode and this is what most of your colleagues expect.


Let me further break down what his opinion was at level of around 1000 AGL it is more than sufficient to use LVL CHNG rather then TOGA since the missed approach altitude might only be be say 2000 or 3000 AGL (airmanship was the word he used)
Airmanship means that you also understand the aircraft you are flying and its systems. Funny story, LVL CHG with CLB thrust at flaps 15 in a very light aircraft will result in a much greater vertical speed than TOGA (which is limited to 1000-2000ft/min unless you press it twice).

downwind 28th Jun 2015 08:01

I would use FL CHNG this is the most appropriate use at 3000' AGL, also bearing in mind that TOGA will not engage above 2000 RA.... thats besides the point.

NG FCOM
With the A/T Arm switch at ARM, the A/T go–around mode is armed:
• when descending below 2000 feet RA
Classic FCOM
With the A/T Arm switch at ARM, the A/T go–around mode is armed when
descending below 2000 feet RA, with or without the AFDS engaged.

However around 1000 AGL I would still use TOGA even if the missed approach altitude is 2000-3000 AMSL (aerodrome based around sea level)***then ask for the appropriate pitch mode*** as required for the situation, bearing in mind the GA situation could have 100 different situations so it is dynamic

Jwscud 28th Jun 2015 09:36

Downwind - TOGA is also armed above 2000 RA with flaps not up/GS captured


FCOM 2 4.20.5

B737900er 28th Jun 2015 11:17

To play devils advocate, what would you do if you are above go around altitude and have to go missed? :E

Ive recently had to break off an approach due to separation being reduced to 2.5nm, thanks to some fantastic vectoring by BCN.

They asked us to break off the approach and still descend to 2300'. I simply disconnected the A/P recycled the FD's asked for a roll mode and level change then reselected the A/P. Sorted no problems.

The problem with TOGA and being within 1000-2000ft of MISAP altitude, is that there is a good chance of a level bust.

RAT 5 28th Jun 2015 12:15

The problem today is guys are taught only one way of doing things. They are not taught how the a/c & its systems works in depth. Often they are not encouraged to use discretion when operating the AFDS and use its capabilities. The SOP says a 'Go Around is accomplished by .............' The first of which is always TOGA. The SOP has been written for a single, simple, scenario at DA/MDA. A PF should know what to do in any simple scenario: how to use the best system and mode necessary for the job in hand. I find it disappointing that guys have to ask how to use the AFDS to make a G/A when above MAA or just slightly below it.
The questioner seems to assume A/T is engaged, as have all the answers.
This lack of thought was demonstrated some years ago, B767 making a night procedural NPA to a visual finals with medium level cloud and good visibility. The F/O turned in too early on the procedural turn (no DME) and failed to configure early enough to slow down. (We did not have rigid trained monkey SOP's. It was pilot judgement going overhead the field and tear-dropping onto finals.) This was an SFO so I hinted rather than coached, but left him much to himself to allow his thoughts to choose & decide. The MAA was 2000', no radar, a clear night and no other airborne traffic. BY now, with only 2 hours fuel on board we were quite light. He disconnected the automatics when visual on finals about 5nm out and started to descend, but he was high & fast. I waited to see what he would do, and at 700-500' I suggested this was not going to work out and called a G/A. He pushed TOGA and selected full G/A power. This over powered beast of an a/c roared skywards, captured the MAA with >3000fpm and would have bust it and stuck the any loose object to the cabin ceiling if I hadn't pulled the power back. We repositioned for a 2nd attempt and this time he gave himself more space, configured earlier and we landed in an normal fashion.
In the aftermath discussion I asked why he had applied full G/A power? The reply was "because you called Go Around." There was only one method to do it. No consideration about doing what was needed to handle the scenario. Black & White, one rule for all occasions, but it caused a consequential problem. The look of surprise when we analysed the event and he discovered that there was more than one way to do it and that as PF you could use common sense to choose. If the MAA was 5000 and required a full clean up, 1 way; if the mAA was 2000' and we were going to keep mid flaps then another way.
Sadly, most airlines I've flown with since have the 'one rule suits all' philosophy. They did not like the guys & gals to think too much. Speaking to friends who fly with 2 different national carriers, they describe they are encouraged to use airmanship to do what is necessary. Every event is different. Sometimes, on a CAVOK day, and ATC asks for a G/A due blocked runway, and you are at 1000', the first thing they might do is pause, no rush, look at PNF and say "ready for G/A" advance the power mid-level and call relevant flaps and climb away in relaxed fashion. Oh that we all had the ability to choose.
One airline had a manual flight G/A policy until Flaps UP. I was at a non radar airfield, low cloud, heavy turbulence, heavy rain, circling in force. At MDA (high) we were not visual and it was only 700' to MAA. Called G/A, FlapsXX gear up and engaged A/P. The look from 2 year 1500hr PNF was astonishment. "Can we do that?" "We just did and don't you think it was a safer idea, especially as the Thunderstorm didn't let us fly the standard missed approach and we needed to ask ATC for different routing and MAA altitude?" Having the automatics in made it all relaxed. It's the way the a/c is designed to be used when necessary. But the SOP says you have to wait. IMHO this would have caused consequential problems; so best to avoid them by using the a/c systems in an acceptable manner. Shock horror, but lesson passed on.

standardset 28th Jun 2015 12:31

Go round from 1000 ft or higher
 
I found on the 757/767, Go Round. Alt Hold. then V/S 1000 ft up works a treat, very smooth and ATC seemed to appreciate the lack of sky rocket mode. The Icelandic incident in Norway is well worth researching.
Bear in mind that from 1000 ft and upwards you are well away from the runway in terms of distance and height and high performance is usually an embarrassment.

Skyjob 28th Jun 2015 20:49

In reference to OP, as you refer to 737, InSoMnIaC is right:

You CAN NOT engage LVL CHANGE unless you get out of the APP mode by pressing TOGA!

Bad instructing done...
Maybe he needs to go into the manuals himself.

Yes, when not in APP mode you could in theory use LVL CHANGE if you have a missed approach altitude set, but this is just altering existing procedures.
Like other posters mentioned about different types, reduced Go Around thrust is initially set and will give sufficient climb gradient unless FULL GA is required with a second push of TOGA.

cosmo kramer 29th Jun 2015 00:23


You CAN NOT engage LVL CHANGE unless you get out of the APP mode by pressing TOGA!
Of course you can. You just press TFR.

Centaurus 29th Jun 2015 03:24

A competent pilot would simply use his professional skills and fly the aircraft manually without all this multi-fingered switching nonsense. The operative word being competent:ok:
Automation dependency has been known to kill people.

cosmo kramer 29th Jun 2015 09:40


A competent pilot would simply use his professional skills and fly the aircraft manually without all this multi-fingered switching nonsense
It's a technical forum. We can discuss what is technically possible without it necessarily being the preferred option.

Anyway, it's as simple as de-selecting the LOC frequency. Autopilot goes into altitude hold, and blank roll mode. From there on you can select other modes, like V/S and LNAV for the missed approach. Be careful with the speed as it obviously may remain at Vref+, depending how far you are in the configuration.

I wouldn't do the above except in the very beginning of the approach. After gear down, I would use TOGA.

Avenger 29th Jun 2015 11:47

Looking at the original post, LVL change versus TOGA at 1000 AGL here we go.. TOGA is a Trust mode that will provide aircraft acceleration and allow flap retraction on schedule, also commands Ground Track and a Known pitch angle 15 degrees, generally recommended according to the FCTM and unless you have a TOGA switch failure is a sure way to climb away.. on the other hand a may not be required in all circumstances. On the other hand, LVL change is a pitch mode that according to the MCP speed will pitch up ( or down) if the target speed is not on schedule, no acceleration is provided without increasing MCP speed and pitch can be erratic. If the autopilot is engaged with no auto thrust additional issues could occur. As observed, at 1000 AGL with APP engaged a de tune of the ILS is required to come out of APP and allow LVL Change to engage, track will be HDG selected at the time.On balance, the workload required is higher when using non-standard go-around procedures. Without APP engaged LVL change of VS with auto throttle can be a smoother event.

mischo1990 21st Feb 2019 17:40


Originally Posted by InSoMnIaC (Post 9026820)
How then does he expect you to engage LvL chg at 1000' if loc and gs are captured.

Just do what boeing says and let him mark you down for it. This will make him look Silly. Not you. Btw i would adopt the procedure he is advocating if I discontinue the approach from higher up but at 1000' you are already established. Stick to the basics. Hit TOGA first and then lvl chg when appropriate (which maybe very shortly after)


I had a SIM session B737 on final ATC says go around cca 250AGL. I hit TOGA nothing happened (TOGA switch failure). A/T, A/P disconnect, Either F/D OFF or reset NAV frequencies and THEN select an appropriate roll and vertical (HDG LNAV, VNAV or LVLCH mode. Using LVL CHG for normal G/A is not according to Boeing procedures. !!

Derfred 22nd Feb 2019 03:18


Originally Posted by Centaurus (Post 9027792)
A competent pilot would simply use his professional skills and fly the aircraft manually without all this multi-fingered switching nonsense. The operative word being competent:ok:
Automation dependency has been known to kill people.

No.

A competent pilot knows:

1. how to fly manually;
2. how to use the automatics properly;
3. how to decide which is more appropriate for the current situation.


Centaurus 22nd Feb 2019 11:41


I simply disconnected the A/P recycled the FD's asked for a roll mode and level change then reselected the A/P. Sorted no problems.

I hit TOGA nothing happened (TOGA switch failure). A/T, A/P disconnect, Either F/D OFF or reset NAV frequencies and THEN select an appropriate roll and vertical (HDG LNAV, VNAV or LVLCH mode. Using LVL CHG for normal G/A is not according to Boeing procedures. !!
After disconnecting the AP why the blinding hurry to re-select the AP and FD when surely any competent pilot would go "Click Click" and simply hand fly? This would minimize the well known risk of mis-selection of multiple modes? That was the message behind that splendid Children of the Magenta Line briefing, still valid from over 20 years ago.


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