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General EFIS and A320-specific questions

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General EFIS and A320-specific questions

Old 30th Sep 2020, 08:48
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General EFIS and A320-specific questions

Hi all,



2 questions if you would



1- weíre usually taught that when changing a value (not mode) on the FCU/MCP, to verify that the new value is reflected on the PFD, and not just the FCU. Has anyone ever seen a situation where the PFD and FCU values are different?



2- A320 specific- When aligning the IRUís, some people do 1-2-3, and others do 1-3-2. Is there any system-related reason that the order should matter? I remember this being discussed at one point, but I couldnít find the thread.

Thanks for the replies.
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Old 30th Sep 2020, 08:54
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Been a while since I flew the Airbus, but:
  1. It's probably policy on any modern aircraft that you don't rely on what MCP/FCU is showing (button lights, values), but rather on what your PFD/FMA/ND are showing. If there was a wiring or some sort of connection problem between MCP/FCU and other parts of avionics, the selected value/mode could potentially not be transmitted to other computers. Never seen it for real, but better safe than sorry.
  2. I believe 1-2-3 is so you remember their positions, should you ever need to switch them off in flight, as 3 is in between 1 and 2 as I remember.
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Old 30th Sep 2020, 09:09
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1. Yes but probably less than 5 occasions over 20 years on F100 and 737. Most usually it's the selected Altitude that will show 100ft difference between the window and the screen.

2. I've not flown the 'bus so no comment.
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Old 30th Sep 2020, 09:28
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Canít comment on the bus but on the boeing you canít deduce the state of the modes by looking at the MCP!

You can see what is deselectable, that doesít give you the complete picture.

e.g.
in alt hold, the mcp button might NOT be illuminated.
an illuminated VORLOC button could be armed not engaged.
an Illuminated AP button isnít necessarily engaged (e.g early part of intended 2 channel approach)

This is why you look at the FMA not the MCP

how the **** do people not understand this? Why is the question even being asked?

Shit training, thatís why.

this industry need to stoo cutting corners and pull its head out of its arse.

FFS. Somebody shoot me.
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Old 30th Sep 2020, 09:54
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1. For the Airbus its not a check that FCU and PFD/ND target values are the same, more to verify that the target has engaged. i.e When in NaV mode you can select a heading value, but if you dont pull to engage it, then NAV mode remains. The FCU only tells half the story. PFD and ND tell the full story!

2. Dont think there is any policy surrounding IRS order to align. I was originally training 1-2-3 sequence with the theory being when you have to switch one in-flight you are more likely to choose the correct one. “So is just a technique”.
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Old 30th Sep 2020, 10:26
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I can second the previous comments on number 2. In one company manual I have even seen it put straight - "the sequence shall be 1-2-3 to maintain awareness of switch location". Although, should you need to turn off an ADIRU in flight, you're not to do so without cross-confirmation from the other pilot as it is a non-reversible action.
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Old 30th Sep 2020, 12:14
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Originally Posted by Check Airman View Post
Hi all,



2 questions if you would



1- weíre usually taught that when changing a value (not mode) on the FCU/MCP, to verify that the new value is reflected on the PFD, and not just the FCU. Has anyone ever seen a situation where the PFD and FCU values are different?

2- A320 specific- When aligning the IRUís, some people do 1-2-3, and others do 1-3-2. Is there any system-related reason that the order should matter? I remember this being discussed at one point, but I couldnít find the thread.

Thanks for the replies.
The PFD and FCU values can be different in a case that is not exactly what you expect : when the pilot mistakes one knob for the other. Turn left heading 230 can soon turn into changing speed to 230kt. Checking on the PFD helps catching and avoiding this mistake.

The order does not matter but it helps pilots remember that 3 is in the middle, to do 1 2 3 instead of 1 3 2 which is more natural.
Originally Posted by Capt Pit Bull View Post
Shit training, thatís why.
Don't judge people or schools so fast..
Everywhere I've been, people have taught me the "act and check" principle or whatever it's called in English.
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Old 30th Sep 2020, 14:07
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Thanks for the feedback so far guys.

To be clear, Iím not talking about mode awareness on the FMA. Iím only talking about the actual numbers. Eg have you ever put 300 in the speed window and had anything but 300 get bugged on the PFD?
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Old 30th Sep 2020, 15:14
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To be clear, Iím not talking about mode awareness on the FMA. Iím only talking about the actual numbers. Eg have you ever put 300 in the speed window and had anything but 300 get bugged on the PFD?
Yes. An SDAC fault can result in more or less random values being sent from the FCU to the FMGCs - both values and modes.
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Old 30th Sep 2020, 17:41
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Originally Posted by Check Airman View Post
Hi all,



2 questions if you would



1- weíre usually taught that when changing a value (not mode) on the FCU/MCP, to verify that the new value is reflected on the PFD, and not just the FCU. Has anyone ever seen a situation where the PFD and FCU values are different?
2- A320 specific- When aligning the IRUís, some people do 1-2-3, and others do 1-3-2. Is there any system-related reason that the order should matter? I remember this being discussed at one point, but I couldnít find the thread.

Thanks for the replies.
As we know Airbus knobs or anything like gear or flaps even are electrical switches not mechanically connected. So it's not enough you put switch on but also need to be check that it has worked e.g. Bulb or fan in a room has started. The chance of getting a different value on FMA/PFD may not be there but the particular switch not affecting the change at all is there. Like pulling ALT is a desire expressed but it needs to be confirmed that the aircraft is doing what was asked. Sometimes you need to pull again.
As far as IRU being switched 1,2, 3 has no systemic issue but to drive it into subconscious the fact that IR3 is in the middle. Because otherwise when dealing with abnormals you may swich off IR3 instead of IR2.
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Old 30th Sep 2020, 17:56
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Thanks guys. My airline has an odd sop where we change altitudes by putting the new altitude into the FCU, and pointing to the FCU. The last operator had us point to the PFD, which made more sense.

Iím told that this is the newest, best way of doing things, so I guess Iíll point to the FCU
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Old 30th Sep 2020, 18:50
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Strange policy. In the first place, I couldn't quite understand if you're required to physically point at the FCU altitude window while reading it out. If yes, why? This sort of parasitic movements are generally discouraged (except for the limited cases of pointing at a control for cross-confirmation purposes) as they increase the risk of something being pushed or moved inadvertently. Also, the idea behind reading the values off the FCU instead of the PFD remains a mystery to me. The FCU is merely an input interface to the autoflight system, just as the mouse or the keyboard to a computer. If it's not communicating properly with the rest of the autoflight system, checking the readings on the PFD is your safeguard against letting the loss of integrity slip unnoticed. I'm all in favour of advancement in workplace practices, but some "new" things literally sound like reinventing the hot water.
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Old 30th Sep 2020, 20:59
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Weíre experts in strange policies. If I made the rules, Iíd just put the airline logo on the Airbus SOP and settle it at that- even with the FMA call outs, which I dislike.

Unfortunately I donít get to write the SOP, so Iíll just adhere to them until they change with the next management shuffle.
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Old 1st Oct 2020, 07:11
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until they change with the next management shuffle.
Which they will as surely as the sun rises!!
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Old 1st Oct 2020, 07:23
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Hi C.A.

1. In 13 years of flying A320/321/330; No.

2. As several have said, to make it a subconscious motor program so your brain knows which ADIRU is which.

On my previous types: Dash 8's and BAe146's, if we changed the Alt, we would keep a finger on the FCU readout until the other pilot acknowledged the new value. Airbus SOPs require a vocalisation and acknowledgement of any change or new value seen on the PFD, so this covers the cross-check requirement. Some on other threads have said their company SOPs for flying Airbus do not mandate this vocalisation. I would say to those companies beware !
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Old 1st Oct 2020, 10:42
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Originally Posted by Check Airman View Post
Weíre experts in strange policies. If I made the rules, Iíd just put the airline logo on the Airbus SOP and settle it at that- even with the FMA call outs, which I dislike.

Unfortunately I donít get to write the SOP, so Iíll just adhere to them until they change with the next management shuffle.
Golden words. I would have done the absolute same. Why does anyone have to pretend that they know better than the manufacturer how to fly the aircraft? Those were the procedures it was tested and certified with, how come that they are suddenly deemed inadequate and unfit for purpose (which is exactly what the heavy "customization" of SOPs suggests)?
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Old 1st Oct 2020, 16:32
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Originally Posted by Uplinker View Post
Hi C.A.

1. In 13 years of flying A320/321/330; No.

2. As several have said, to make it a subconscious motor program so your brain knows which ADIRU is which.

On my previous types: Dash 8's and BAe146's, if we changed the Alt, we would keep a finger on the FCU readout until the other pilot acknowledged the new value. Airbus SOPs require a vocalisation and acknowledgement of any change or new value seen on the PFD, so this covers the cross-check requirement. Some on other threads have said their company SOPs for flying Airbus do not mandate this vocalisation. I would say to those companies beware !
I like the finger on the FCU technique. Iíve never had to vocalise anything but altitudes though. Iíve seen a few YouTube videos and it seems tiring- to be generous. Still, Iíd be more comfortable following Airbus SOP to the letter than some random guyís technique.
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Old 1st Oct 2020, 16:33
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Originally Posted by PilotLZ View Post
Golden words. I would have done the absolute same. Why does anyone have to pretend that they know better than the manufacturer how to fly the aircraft? Those were the procedures it was tested and certified with, how come that they are suddenly deemed inadequate and unfit for purpose (which is exactly what the heavy "customization" of SOPs suggests)?
Because ďweíve always done it this wayĒ.
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Old 1st Oct 2020, 17:12
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Originally Posted by PilotLZ View Post
Why does anyone have to pretend that they know better than the manufacturer how to fly the aircraft? Those were the procedures it was tested and certified with, how come that they are suddenly deemed inadequate and unfit for purpose (which is exactly what the heavy "customization" of SOPs suggests)?
Sticking to Mr. Boeing/Airbus SOP has a distinct disadvantage - it means the airline's SMS has nearly zero input into it, and the input it might have, will have an enormous latency between the line events and the implementation of the SOP change that seeks to eliminate similar events from occuring.

Manufacturers cannot predict every single operational environment in the world, and these will vary a lot between airlines - e.g. requency changes over Africa, where all frequencies have a single decimal number and occur once every hour pose less risk of dialing the wrong frequency, getting into PLOC and perhaps even getting intercepted than operating in Maastricht/Rhein area in EU, where you have 8.33 frequencies, and changes less than 5 mins apart.

Similarly, pointing to MCP/FCU might seem silly to somebody who operates in airspece, where you get five level changes in the entire flight, but it might - possibly - make a small bit of sense when you operate 4 or 6 sector days into London TMA, FRA, etc., where you often get 20 level changes on the way up and 20 on the way down.
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Old 1st Oct 2020, 17:40
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To be clear, things like you're describing are ok to tweak a bit, in my opinion. My airline however, has a tendency to change more consequential procedures- like flight control checks, go around call-outs and splitting of duties during critical phases. That kind of stuff, you shouldn't mess with, no matter how well it worked on the DC3.

The SMS folks should absolutely have a say in the SOPs for a given operation. As you said, different theatres present different challenges, but their recommendations shouldn't go contrary to the manufacturer's SOP.
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