A330 PFD Indiatication

[FollowTheProc]

Pilots, can anyone kindly explain to me how would we know whether the system is in ALTN1 or ALTN2, just by looking at the PFD?:8

[FollowTheProc]

Thank you goeasy!

The FCOM does mention ALTN1/2 though! It doesn't matter, I guess!

[PGA]

You can't tell by just looking at the PFD, but it depends on the severity of the failure, in some cases you keep ALT 1 with a few more protections then when you end up in ALT2.

FCOM 27-20-20 Alternate Law explains it.

[FollowTheProc]

Thanks very much, PGA! I will look it up.

[A320baby]

Basically you cannot tell if you are in ALT 1 or 2 BUT IN ALT 1 you have AOB protection

[vilas]

No you cannot see on PFD. Also it shouldn't matter because you should not be flying outside the flight envelope to need it. However not having herd in years of flying Bus is scary because there may be many other thing that you haven't herd of.

[ACMS]

Yes the PFD does show the difference.

In ALTN 1 you can loop the Jet ( in theory!! ) with no pitch limit protections and as such the double green protection symbols are not on the pitch scale, replaced with yellow x

In ALTN 2 you can loop and roll the Jet, as such the double green protection symbols are not there at 67 deg aob or 30 pitch up and 15 down, replaced with yellow x

So, The PFD enhances the situational awareness of the status of the flight controls and you can see which protections are lost by simply looking at the specific symbols ( =green )


Easy.

All in your FCTM

[vilas]

Sorry I was talking about A320.

[ESCAT]

ACMS:

Speaking specifically about the A330, FCOM DSC-27-20-20-10 note (4) says that

"Bank angle limitation remains effective in ALT 1, which uses roll normal.
However, since ALT 1 is generally an unprotected law, all protection marks on the PFD are in amber for simplicity."

Even in ALT1 the amber marks for the Angle of Bank protection on the PFD will be amber, even though Angle of Bank protection is still available.

Thus as far as I know, there is no way to discern from the PFD whether you are in ALT1 or ALT2.

[ACMS]

My quote regarding using the symbols on the PFD to see which protections are lost are straight from the A330 FCTM.....

I do recall seeing just that in the SIM but it was a while ago.

It wouldn't be like an Airbus FCOM to be misleading now would it !!

[ESCAT]

Looking in the FCTM, OP-020, Indications section says the following:

"When protections are lost, amber crosses (X) appear, instead of the green protection symbols (=)."

The picture below it then shows the PFD in 3 configurations, Normal Law, Alternate Law and Direct Law. In the alternate law picture all of the protection symbols are replaced with amber crosses including the Angle of Bank protection indicators. It does not differentiate between ALT 1 or ALT 2.

If the airplane is in alternate law, ALL off the protection symbols are amber, regardless of whether the A of B protection is lost.

The FCTM does seem to agree with the FCOM in this case, although admittedly it is not quite as specific.

FCOM: "Bank angle limitation remains effective in ALT 1, which uses roll normal.
However, since ALT 1 is generally an unprotected law, all protection marks on the PFD are in amber for simplicity."

From both the FCOM and the FCTM I understand the following: You will never have some amber crosses and some green protection symbols. It is all or none. And thus you will not be able to tell if you are in ALT 1 or ALT 2 by looking at the PFD.

[Uplinker]

Wow! Been flying 330 for years. Never heard of ALTN1/2 ever...



Wow indeed. I wonder who did your type rating tech, and are you saying that you have never read the books?

[Romasik]

Is there any practical use of knowing difference between ALT1 and ALT2? How would you use this wonderful knowlegde?
You get your rating after CBT, FTD, and FFS. Few weeks. You don't have time to read all 10 kg of FCOM. Reading and deeper undestanding comes later.

[FollowTheProc]

Thank you very much everyone! Very useful understanding of the system and associated display. (I did learn what I expected to learn).

[vilas]

The manufacturer has provided it with some purpose. Ignorance of flight control system in FBW is not good. In alternate 1 with manual thrust if you happen to drop speed the aircraft will pitch down below VLs while in Alt2 it will keep loosing speed and keep trimming all the way to stall. In A330 In roll there is protection in Alt1 but not in Alternate 2. The worst thing if someone didn't bother to read in years and this professionalism then why waste time asking any thing on PPRUNE? Better to enjoy a movie.

[fantom]

Uplinker and Vilas, you are correct.

I hope he is not really a pilot.

Dreadful.

[Romasik]

The manufacturer has provided it with some purpose. Ignorance of flight control system in FBW is not good. In alternate 1 with manual thrust if you happen to drop speed the aircraft will pitch down below VLs while in Alt2 it will keep loosing speed and keep trimming all the way to stall. In A330 In roll there is protection in Alt1 but not in Alternate 2. The worst thing if someone didn't bother to read in years and this professionalism then why waste time asking any thing on PPRUNE? Better to enjoy a movie.
These are the last things you will be thinking about when you are in trouble that led to ALT Law. Just fly the aircraft.

[vilas]

Lack of knowledge of alternate law in flight control system is dangerous. It is shocking that year after year he can be cleared in tech refreshers. If you think ignorance makes you a better pilot then I can only wish you good luck.

[Uplinker]

vilas, I completely agree :ok:

Wow again.

The point is, Romasik, if a so-called pilot has "never heard of ALT1/ALT2 law", then it shows that they have never read the books, that is the shocking thing here.

With a FBW, (or in fact any) aircraft, understanding - or at least knowing about - control reversions in the event of failures is a very fundamental thing.

How much else about the aircraft does this person not know about. How did s/he pass their type rating?

:mad:

[Romasik]

Lack of knowledge of alternate law in flight control system is dangerous. It is shocking that year after year he can be cleared in tech refreshers. If you think ignorance makes you a better pilot then I can only wish you good luck.
I know what ALT law and it's variations are and refresh this and many other things every time before the simulator as it's always preceeded by quite a serious oral. And I have to admit that I never think about it during the simulator session. Whatever situation is. I'm just flying the aircraft and never think about protections. They don't exist for me. In any law. Protections are there if you personally fail.
That's why I'm wondering how you guys use your wonderful knowlege practically? You somehow prepare yourself, that you don't have this particular protection? And with protections you just relax and leave your fate to them?

[vilas]

Whatever situation is. I'm just flying the aircraft and never think about protections. They don't exist for me. In any law. Protections are there if you personally fail.

If you were handling GPWS warnings and didn't know protections exist your actions will be less than optimum won't that compromise your escape?

[CaptainMongo]

"We must not allow mastery of the Flight Management System to be confused with airmanship." Understanding AF447 Bill Palmer

Palmer also goes into some detail about this thread topic, and insufficient pilot understanding of the Airbus FBW system, its possible degradations and those effects on aircraft handling.

[Romasik]

Whatever situation is. I'm just flying the aircraft and never think about protections. They don't exist for me. In any law. Protections are there if you personally fail.

If you were handling GPWS warnings and didn't know protections exist your actions will be less than optimum won't that compromise your escape?
Probabilty of these two events happening at the same time is nearly zero. I have never had GPWS event, that forced me to pull full stick backwards, or ALT Law in my life. Nor I heard about such situation. And you are talking about both of them happening together? May be it would be wiser to use your brain energy to avoid getting into PULL UP situation in the first place?
I'm serious. No matter how many times I read this kind of stuff, most of it eveporates after few days or weeks. It's useless to try to always remember thousands of things that you don't practice in every day life. General system knowledge, SOP, limitations, memory items - that's what we need to remember. Other stuff - to be able to quickly locate and read, if you need. And yes, you have to have prior knowledge of that particular topic. If you are so gifted to keep it in your head for immediate use - fine. But there are few of pilots of this kind. Overwhelming majority are just regular pilots with average pilot's abilities.

[vilas]

Probabilty of these two events happening at the same time is nearly zero.

Interesting viewpoint ! Statistically the possibility of an engine failure is one 30 years and dual engine flameouts none whatsoever. So if you have less than thirty years to retire you can safely delete from FCOM the EFATO, dual engine flameout, the entire OEI performance. Same with Dual hydraulic, EMER ELEC and most other problems. Wow! The FCOM can be carried in back pocket.

[goeasy]

My original comment was relating to ALT'N'1 etc... As there wasn't reference to control laws in OP.

Too many heros in aviation, thinking they remember all these details immaculately, when the average of us manage keeping the wee white box close to centre of PFD (wings level) makes all the limits irrelevant.

Don't panic, if I get close to any of the limits, at any stage, outside the sim, I will seriously consider handing my licence in!

I am sure there are a few who could recite FCOM verbatim whilst wrestling an inverted 330 but I have no desire to be one of them.

[applecrumble]

Statistically the possibility of an engine failure is one 30 years

Is that true? Interesting statistic.

I agree with Vilas. I'd rather have more knowledge than less, especially with the AB.

[Romasik]

Probabilty of these two events happening at the same time is nearly zero.

Interesting viewpoint ! Statistically the possibility of an engine failure is one 30 years and dual engine flameouts none whatsoever. So if you have less than thirty years to retire you can safely delete from FCOM the EFATO, dual engine flameout, the entire OEI performance. Same with Dual hydraulic, EMER ELEC and most other problems. Wow! The FCOM can be carried in back pocket.
You chose to answer to the most unpractical part of my post, ignoring more realistic things...
Anyway, events, that you mentioned are definitely regarded by Airbus as probable and we have real life examples of those. Nothing about simultaneous GPWS PULL UP event in ALT Law though. And, BTW, the only difference between ALT1 and ALT 2 in this sence is absence of gentle nose down signal in a very specific case of 2 ADR lost. We are talking about even smaller probabilty and a signal that you won't even notice in those circumstances. What you really have to know and watch is that protections are lost. You will be warned about it by ECAM and/or QRH and never pull full stick backwards. So, I don't understand what you are talking about. The loss of that gentle signal in the event that statistically impossible and never even mentioned in any Airbus publication?
It's up to you, of course. You are free to fill your memory with this kind of stuff if you have enough capacity and keep reading to ensure you don't forget. My concern is also very practical - the check airman on the oral or check ride that has similar view on the importance of things that he's taking from his head.

[Romasik]

Is that true? Interesting statistic.

I agree with Vilas. I'd rather have more knowledge than less, especially with the AB.
I had 5 engine failures over my 35 years of flying. 3 of them on 4-engine aircraft, and 2 on 2-engine.
Absolutely agree about more knowledge. One small remark: it has to be reasonable. If you go deep to the level of differences between ALT1 and ALT2 protections, the scope has virtually no limit. There are so many much more important things at higher levels and I'd rather spend my time and energy there.

[vilas]

Statstics is like that. 99% means nothing to the 1% guy to whom it happens. What I quoted was from a book on jet engines. and I am not considering GPWS and alternate law together. Even in in normal law if you didn't know the protections then you'll be hesitant to pull full back stick. And why have GPWS? The aircraft shouldn't be in that situation according to you. But pilots have landed with gear up didn't they? So knowing the difference between having and not having GPWS helps.