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-   -   A320 FMA ''G/S'' callout (https://www.pprune.org/tech-log/612875-a320-fma-g-s-callout.html)

PEI_3721 3rd September 2018 15:53

Re #20, the most important aspect of a callout is to report the system condition enabling both pilots to have a common understanding of the situation. That can be very difficult depending on the context of the situation and what is actually happening.
The ‘golden’ mantra for the need to understand the FMA requires additional clarification with respect to what the aircraft auto-systems are doing, have been programmed to do, or the crew’s intention and the expected changes; it’s far more important to understand what the aircraft is actually doing than what the FMA indicates.

A problem in calling all ‘normal states’ is that this can lead to ‘wish think’ - you think that you have said the words, but may not have; or ‘hear think’ - you believe that an expected conditions exists, but in fact does not.

The better approach is to only call the undesirable states - ‘no glideslope’, at a time when it should be armed / engage. This has the advantage of reducing ‘callout clutter’ (soggy SOPs), such as GS armed, GS engaged, GS star/dual, etc.
Unfortunately this ‘deviation’ only method requires that both crew have a common understanding of what is intended; standard procedures could help, as might a good briefing, or improved cross crew communication; so FMA callouts are used for this but may not be the best method.
And then again with positive calls there is potential confusion by intermixing normal and abnormal states using the same words. e.g. GS mode armed / engaged vs GS deviation in auto flight or the GS component of an unstable approach.
Your choice, but choose carefully.

Check Airman 3rd September 2018 16:12

Lexis,

How does your captain read out AP1, AP1+2 and OP CLB?

If he's going to get silly, you should match him. Read out the FMA letter by letter on takeoff. That should get him to see how silly he's being.

pineteam 4th September 2018 04:37


Originally Posted by PEI_3721 (Post 10240388)
A problem in calling all ‘normal states’ is that this can lead to ‘wish think’ - you think that you have said the words, but may not have; or ‘hear think’ - you believe that an expected conditions exists, but in fact does not.

The better approach is to only call the undesirable states - ‘no glideslope’, at a time when it should be armed / engage. This has the advantage of reducing ‘callout clutter’ (soggy SOPs), such as GS armed, GS engaged, GS star/dual, etc.

I could not agree more. I believe it would make more sense to call out unexpected conditions. I don't understand why we need to call ''ALT*'' then '' ALT''. Like oh wow, what a surprise! Like why not focussing on the non normal state instead? I know, some will argue that's the only way to crosscheck we both have checked the FMA... But if both pilots do their FMA scan properly, they would pick it up quickly if something is odd. Anyway, I'm getting paid to read out loud the FMA, so I will keep doing it. Except when left alone in the flight deck.. xD
Same goes for the guys calling '' Clear right side'' every 10 seconds during taxi while barely looking out. Like dude, I'm not blind. Why don't you keep looking outside and call my attention only when there is a threat? Keep your energy for God Sake.

45989 4th September 2018 06:46


Originally Posted by Check Airman (Post 10239898)
The level of pedantry on this thread makes me thankful that for better or worse, my company does not make FMA calls.

Hear Hear! Remember when flying the aircraft was more important than SOP's.............

vilas 4th September 2018 07:36


A problem in calling all ‘normal states’ is that this can lead to ‘wish think’
It is called confirmation bias. But every procedure has it's negative. Firstly these are not call outs but read outs, there is a difference. Normal changes are read to force you to look. If you want to call only the undesired condition then you are going to be silent most of your life and then why would you monitor at all? Ask SFO guys not one but three of them none noticed idle Thrust or falling airspeed. Why because the system always keeps everything in order( unless it doesn't). So it's not a job of line pilot to make procedures because most don't have the knowledge of the design process, human engineering or psychology. Leave it to the manufacturer, at least ask him before you change. Lot goes into designing an airplane. How many of us know why when heading is pulled CLB changes to OPCLB but DEC changes to present VS and not OPDES?

pineteam 4th September 2018 08:28


Originally Posted by vilas (Post 10240910)
How many of us know why when heading is pulled CLB changes to OPCLB but DEC changes to present VS and not OPDES?

Hi Vilas.

I dunno. Please share the reason. If I had to guess: I would think to avoid unnecessary thrust variation. Turbine engines don't like thrust variation. And also it's safer I suppose.Going from ''DES'' to ''OP DES'' would possibly means going from -500/-1000 feet a minute to a much higher rate of descent as the engines would go to idle.

vilas 4th September 2018 10:11

Hi pineteam
Let some more guesses come in. The point I am making is the amount of thought that goes in designing an aeroplane. So it shouldn't be brushed aside merely on personal opinion.

CaptainMongo 6th September 2018 23:14


Originally Posted by vilas (Post 10241018)
Hi pineteam
Let some more guesses come in. The point I am making is the amount of thought that goes in designing an aeroplane. So it shouldn't be brushed aside merely on personal opinion.


OK, I’ll play.

In CLB thrust is fixed. Therefore changing from NAV to HDG will have no effect on Aircraft trajectory. The engineers know the thrust setting in CLB is always CLB

Conversely, In DES thrust is variable from IDLE to SPD/MACH. My guess is the engineers are trying to minimize the variable state of thrust in DES by using a mode reversion to force thrust into the SPD mode.

This is the same reason when changing at the FCU altitude during ALT*. Thrust is variable during ALT*, therefore a mode reversion to SPD is forced to set a fixed thrust setting.



FlightDetent 7th September 2018 12:05

a) The basic rule is that the A/C must never do anything that is un-commanded. Pitch-up and pitch-down included.
b) The reversion is a reaction to what is effectively a failure of the DES mode (unable to compute), and that - just like on any other aircraft - must be fail-passive. I.e. ok-to-fail-but-need-to-stay.

In the very likely case when the DES is following a V-NAV geometric segment (60% of the time, my guess), or not flying exactly at the target speed (almost all of the other time), the reversion from DES to OPDES would either
- (1) set IDLE THR and dive the aircraft for the speed
- (2-i) increase pitch and the descent rate to accelerate towards the IAS target
- (2-ii) reduce pitch and the descent rate to slow down towards the IAS target.

Either of those would be a violation of the basic FBW design principles ("a" above) or certification predicaments ("b" above).
Or in simple layman's view: DES is V-NAV path (geometrical trajectory) mode. Once you invalidate that by pulling HDG, V/S is the next closest thing. OP DES is most definitely not.

[Dislclaimer: I enjoyed HDG+V-NAV on the 737.]

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

I think that vilas had actually something else as his main point, this was just a side-quest.

It is that designers of the aircraft and of the procedures work in tight coordination to give us a carefully assembled product that is safe, proofed against human error as much as possible. And go seriously wide and deep to achieve that, embracing all the experience the fleet has accumulated in 25 years worldwide. Those who disregard manufacturer's advice given through OEM's FCOM SOPs are brave, bold and playing with fire. It can be done, but to do it right the resources needed are enormous and result never better than the original. More likeable? Sure, but not better.

Think of this one: The aircraft is born and released to the world with the following legal and binding documents
- Noise Certificate
- W&B Manual
- AFM
- ECAM
- QRH
- MMEL
Not the FCOM. FCOM is just a suggestion for operating it inside the limits set in the above certification package. If you re-create the FCOM, do you also re-create the MEL OPS-PROC section? If not, do the MMEL procedures still fit against the SOP's that you have? Similar for OEB's. Just an example.

It is human to think to know better, applies to chief-pilots and CAAs (!) as well. Some steer away from the desire, some fall for it, only few make it through. Hat's off to them, though the whole endeavour is of a questionable motivation.


my 3pc

vilas 7th September 2018 19:42

FD
All of what you wrote is correct including the answer to my question. I had received a reply similar to that from the Airbus. The point I was making as always is without consulting the manufacturer don't change or manufacture procedure. It's not that simple. I am never tired of quoting the incident involving JetStar Australia and two other airlines of badly busting minima in poor visibility because they changed the priority of reading FMA during go around. It could have ended in tragedy. It is very simple to fly the Airbus but not that simple to understand it deeply. To keep it that way just fly the way it is recommended. Otherwise dig through the manuals write down every thing you don't like or understand and ask the manufacturer. It is very time consuming.

Capn Bloggs 8th September 2018 04:39


Originally Posted by Flight Detent
[Disclaimer: I enjoyed HDG+V-NAV on the 737.]

I do too. What precisely is the problem with staying in VNAV while using Heading to zip around some weather on descent? Probably the same "team" that decided "that thou shalt not be in VNAV in HDG" that decided that the controls would not have any feedback to the other pilot because that was the best way...


Originally Posted by Flight Detent
Not the FCOM. FCOM is just a suggestion for operating it inside the limits set in the above certification package.

That's ridiculous. The job is hard enough as it is without having to refer to the AFM as well. Do you refer to the AFM as the primary method of operating the aeroplane?

I can think of a few dumb designed-in features/procedures...

FlightDetent 8th September 2018 20:00


Originally Posted by Capn Bloggs (Post 10244013)
The job is hard enough as it is without having to refer to the AFM as well. Do you refer to the AFM as the primary method of operating the aeroplane?

Agreed; you read me wrong. Of course, I use FCOM to fly it, also in order to not reference the AFM.

The certification package is AFM, MMEL, CDL, W&B, like 4 puzzle pieces. The FCOM / OEM's SOP set serves as a frame to them, so I can handle the big picture without studying the individual pieces and how they snap together. The debate above was about some inevitable consequences of modifying the factory guidance.

RUMBEAR 23rd September 2018 09:49

Anyone pilot who can truely answer that question is wasting their talents flying !!

pineteam 23rd September 2018 11:47


Originally Posted by IBE8720 (Post 10256047)
Why do some pilots ALWAYS call CAT 3 Single when they diconnect the Auto Pilot?
No aircraft can be do any sort of Auto Land with no Auto Pilot. Why not wait till the aircraft downgrades to Cat 1?
We don't select Flap or Gear and then call Intermediate setting while waiting for the system to achieve the desired setting.
​​​​​​

I never call it also. A colleague was PF once flying with a junior FO and when he armed the approach and called «CAT2 ». The PM undestood « FLAPS 2 » and set the flaps... Luckily, the speed was below VFE. But after hearing that case, I can see how easily a flaps overspeed can happen. Of course PM should check the speed first, but as a precaution I’m never calling « CAT2 » when I arm the approach.
Also, unless Your SOP is different but in our SOP, if you have already Runway in sight and called « Runway continue » with AP off, it’s not required not useful to call out « land » on FMA or « Checked » after the auto call out « 100 above » and « runway continue » at minimum. But still lots of people are doing it.

Uplinker 23rd September 2018 15:24

I have always said “lock star” for LOC* and “glide star” for G/S*

I don’t remember if these were my own invention or what we were told to say, but the phrases seem to work fine and have never been confused for anything else.:ok:


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