A320 quiz

[catchup]

Assuming you are in cruise flight, advancing thrustlever one to the TOGA detent, number two remains in climb pwr detent. Yes, engine one runs now at TOGA. What will engine two do?

a) running at TOGA as well
b) doesn't care, remains at current rpm
c) slows down to idle
d) shuts down by a protection

[Spearing Britney]

Engine one wont go to TOGA at all, assuming of course you are at a normal (say above FL300) cruise level! Now you tell me why...

[FlapsOne]

Thrust Lvr Asym max power MCT ???

[catchup]

@Spearing Britney

Are you sure...?

@FlapsOne
No, but nice try..

[Spearing Britney]

Certain, cos at a typical cruise level CLB=MCT=TOGA! You may change the FMA but the engine output can go no higher than the CLB limit no matter if the levers are advanced to MCT or to TOGA.

Only at low levels is TOGA>MCT>CLB, they come together as you climb and meet at FL250 or thereabouts...

[mcdhu]

.....a bit like the FCOM really!!

Cheers,
mcdhu

[catchup]

Spearing Britney is correct, the FMA says TOGA but engine one runs at MCT/ climb thrust. Anyhow, what about engine two?

regards

[idg]

FMA says MAN TOGA and flashing LVR MCT, #2 stays at thrust necessary for managed (or slected) speed as the autothrust stays armed, dependant on whether #1 achives more thrust.

[catchup]

@idg

Sorry, no.

[idg]

Well that's what our sim does!!

[catchup]

o.k.

Answer a) is correct. Number two runs at the same rpm like number one does even with it's thrustlever in the climb notch.

regards

[Preppy]

CATCHUP

Questions for you!

1. CFM or IAE or both?

2. What technical manual reference have you found?

3. Have you cross-checked the validity on a sim? Which manufacturer?

Thanks :D

[catchup]

@Preppy

Questions for you!

1. CFM or IAE or both?

2. What technical manual reference have you found?

3. Have you cross-checked the validity on a sim? Which manufacturer?

1. Both, types flown and observed A319/320/321
2. Didn't look for that. Found out bei chance.
3. No, I didn't.

regards

[Spearing Britney]

Yeah but its not really TOGA is it?

Answer e) runs at clb limit

As bad as the JAA questions! I only make the point because it is significant at lower levels , you wont get toga out of number 2 by putting number 1 to toga below FL245 ish - the detent is always the limit.

[catchup]

@Spearing Britney

That's what the book of a large bus-airline says:

The pilot can always get MAX TO thrust by pushing the thrust lever all the way forward.

regards

[mcdude]

Hi everyone, good question and here's a contradictory cut & paste from the A320 FCOM;

1. If one or both thrust levers are beyond the MCT detent, the engine instrument display shows TOGA.

OK no arguments here.

2. If the thrust levers are not aligned, an asymmetric message (ASYM or LVR ASYM) appears on the FMA. If so, each engine is limited to its appropriate TLA. This allows the use of autothrust to continue if one engine has to have its maximum RPM limited for some operational reasons such as excessive vibration.

Maybe idg was right!

3. The pilot arms A/THR : in flight ... while A/THR being active (A/THR white on FMA), the pilot sets (one) thrust lever ...above the MCT detent.

Or maybe idg (or his sim) is wrong (A/THR armed not active)

4. The pilot can always get MAX TO thrust by pushing the thrust lever all the way forward.

A translation mistake? ie should be levers (plural)

Maybe I've raised more questions than answers????

mcdude

[catchup]

@mcdude

Try it out!

I did and it worked like I said.

NO ASYMMETRY WARNING, cause it's not an ATHR mode!

regards

[FlapsOne]

FCOM 1.22.30

LVR ASYM Amber

One thrust lever is in CL or MCT/FLX detent, and the other one is not in this detent.

-----------------------------------------------------------------

So that's a lie then, is it?

It may well be out of (above) the ATHR range, but the system is still surely telling you that there's something wrong with one of the levers that it can't do anything about. Therefore it throws up the FMA inviting your intervention.

Still think MCT is the best you'll get out of the motor, irrespective of what the FMA says.

I would like to see some reference for answer a) to be totally correct.

[Preppy]

Catchup

Just tested your theory in a IAE A320 simulator (at FL120) - you are correct!

[catchup]

Preppy

Fine!

Like I said, it's not a theory I've observed it in real.

regards

[manuel ortiz]

A-320 Fam. IAE V2527 EA5
TOGA will show up on ECAM if you push that T/L all the way forward but TOGA THRUST may or may not be obtained.

A certain Mach and or altitude will limit first to MCT and then a higher Alt to Climb. ( Mach no longer a factor here)

MO

[catchup]

@manuel

TOGA, MCT or Climb thrust, that wasn't the main concern of my thread. The point is, engine two with its thrustlever in the climb detent will follow the thrust command of thrustlever #1 set to TOGA and running at same rpm like ENG #1.

regards

[manuel ortiz]

Catchup,

Must say I don't agree with your second statement.

Here's what I would expect:

Engine two with its thrustlever in the climb detent will just stay or accelerate to its corresponding thrust lever angle position, Climb detent in this case.

Why? Well, selecting #1 T/L to TOGA will make auto thrust inactive, it will go to it's Armed mode making each engine go to its TLA thrust.


#1 can now give you either TOGA, MCT or CLB ( TOGA displayed on the upper ECAM)
Again...#2 will NOT really "Follow" now #1 !! Its just going to it's thrust lever angle thrust.
Could they both go to TOGA thrust ?
NO ( #2 is limited by its detent)
To MCT ?...........NO ( Same as before )
To CLB ?...........Yes, that could be seen and knowing that TOGA will show up on the upper ECAM and that both RPM's could now be seen accelerating to the same RPM is something which can create confusion.

That´s the way I see all this.


Brgds.

Manuel Ortiz

[catchup]

@manuel

BOTH engines follow the TOGA thrust command of TL #1. TL #2 in CL detent.

I've obseved this in flight on A320/319/321 with both, CFM and IAE.

By the way, if you look to the post of "preppy" he/she confirmed it in the SIM.


regards

[idg]

Have tried it in the sim again and the thing is that there is (obviously) very little difference between the TOGA demand and CLB rating at altitude. On first glance it does indeed look as though the #2 (in your example at CLB notch) goes to TOGA and the thrust rating value on the upper ECAM changes as one would expect to TOGA.

In fact closer inspection of the EPR doughnuts (and finally EPR value) shows that #2 stays at CLB rating and that there is a (albeit) very slight difference between the two engines, #1 being at TOGA.

The way to absolutely confirm this of course is to do it at low level but have not had the chance to do this yet...will report further.

[manuel ortiz]

Just tried it out in the SIM and reafirm my posts. Worked as it should.

Preppy, maybe you were kind of in a rush or at high altitude were this all can get misleading. Suggest you check it out again.

Manuel

[Preppy]

manuel ortiz & idg & Catchup

OK. I've had another & more careful look at it in the sim. At FL 100, the indications that I saw today are exactly as idg describes in his most recent post.

:)

[manuel ortiz]

IDG & Preppy,

Good job !!

Manuel

[CS-TMX]

From A330-300 FCOM:

EFFECTS OF THRUST LEVER MOVEMENT WHILE A/THR IS ACTIVE

When both thrust levers are set above the CL detent (both engines operative) or one thrust lever is set above MCT (one engine operative) the A/THR reverts from active to armed. "A/THR" turns to blue on the FMA and the thrust levers control the thrust directly. The FMA displays "MAN THR" white in its first column.

Best regards

[FlapsOne]

CS-TMX

We know that much, that's not the question.

[manuel ortiz]

Flaps One, sorry, do you feel Catchup´s misunderstandings have not been allready covered as to understand the real thing which goes on when he sets one T/L to TOGA with other one at CLB?

[FlapsOne]

Nope.

Just pointing out, that section of the FCOM does not give the answer to this question.

[catchup]

manuel

Yeah, that's the point. One engine follows the thrustlever command of the other engine. That's what me surprised. But it's interesting to see how it is desribed in the manuals and how it is understood by the users.

regards

[manuel ortiz]

Catchup,

You still wrote: .... One engine follows the thrustlever command of the other engine.
---

Don´t know what goes in your mind when you say that but believe the statement can be very misleading.

Two guys tried this in the SIM and both had to correct their initial observations so just in case something is still not making sense for you feel free to say it. That´s what this is all about.

Your thread was/is very good food for thoughts.

[email protected]

[FlapsOne]

Dear all

The thing is, the scenario as described, IS NOT covered in the manuals at all.

The FCOM refers to

BOTH levers.........BOTH engines operating
or
1 LEVER ..............1 Engine operating

Buit not 1 LEVER, BOTH engines operating.

So the Sim might be right, but who cares? Why would you want to do it anyway?

[idg]

F1,

I initially thought as you do...who cares and why would you want to do it anyway?!

Then it occurred to me that it would actually be easy to knock just one of the levers to the TOGA detent...a slip as a hostie passed a meal tray, someone stumbling as they tried to get into the seat etc.

If it was done unintentionally, as we have seen in the sim, apart from the FMA, the indications on the engines are quite symetrical so no obvious clues there. Main thing is that the autothrust is no longer active and the aircraft will accelerate towards Mmo and an overspeed.

Agreed not likely....but possible!

idg
;)

[manuel ortiz]

F1

How about also a TOGA take off, high vibration on one Eng and you at some point during your second segment wanting to try lower RPM´s on the shaking one with still TOGA on the other.
The message which I felt was about to be left here was that going i.e. to CLB detent would still provide TOGA RPM´s.

Manuel
X-320

[catchup]

Unfortunetly I don't have the opportunity any more to check it out on the A340. TL one to TOGA and three more engines will follow to what ever thrust.....?

regards

[saman]

Unless I'm mistaken, TOGA is not normally available above 14,000 ft. I think that one of the changes needed to operate the A319 at Bangda - the only airport that is over 14k methinks - is to mod the FADEC(s) to get TO thrust at this altitude. Who needs TOGA when you're not doing a TO or a GA? So, when you're looking at this in the sim, you just may get different things either side of the 14k line.

[catchup]

@saman

quote

<Who needs TOGA when you're not doing a TO or a GA?>

Again, that's not the point.

Who expects engine two to follow thrust command of thrustlever one? (And vica versa)

That's the point.

regards

[idg]

Catchup,

Have to disagree with your statement " Who expects engine two to follow thrust command of thrustlever one? "

The whole point is that it is not following the #1 thrust lever movement at all. By moving the #1 you happen to disable the Autothrust which causes the #2 to accelerate to CLB thrust. It is not moving to follow #1 at all!

idg

[catchup]

@idg

O.k., you made it! You are the winner of the little quiz. Missed to talk about the award. To my knowledge idgs need oil. Which type do you prefere? Heineken, Beck's or Michelob?

regards

[idg]

Catchup,
San Miguel for me!!
idg:ok: