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novice110
27th Apr 2019, 14:28
Hi,

Reading an ATSB report on an A320 with unreliable airspeed near Perth, Western Australia AO-2015-107.

[/QUOTE] In the A320, flight crew are able to examine the ADR angle-off attack values; however, they are not presented on the primary flight displays, and require the flight crew to access and display a page on the multipurpose control and display unit in the centre pedestal. In this occurrence, the flight crew discussed an angle of attack discrepancy, but for undetermined reasons did not access the angle of attack page to confirm the discrepancy. [QUOTE]

How common is it to check the AoA in flight to troubleshoot an ECAM of NAV ADR DISAGREE ?

How do you access this info ? FCOM have any guidance ?

Jonty
27th Apr 2019, 14:45
MCDU MENU/AIDS/ALPHA DISPLAY/AOA. It will then give you the respective AOA for each ADC.

Its not an approved procedure, so I’m surprised that the ATSB have come to that conclusion.

We used to have a list of all the ALPHA codes that you could display in the MCDU, but it’s long since been lost.

Sergei.a320
27th Apr 2019, 14:45
MCDU MENU-AIDS-ALPHA CALL UPS - AOA

gearlever
27th Apr 2019, 15:19
alpha codes (http://mobile.airlinetechs.com/airbus/callups/alphamenu1.html)

sonicbum
27th Apr 2019, 16:11
Hi,



How common is it to check the AoA in flight to troubleshoot an ECAM of NAV ADR DISAGREE ?



Not common as it is not a procedure nor the purpose of the AIDS function which is to monitor and record many different parameters so that they can be analysed when appropriate. It is common during line training of new type rated pilots to call up a few pages just to show the trainees the capabilities of the system and possibly induce some technical & aerodynamics chats but that's it. Definitely nothing to mess with during abnormal procedures.

FlightDetent
27th Apr 2019, 18:42
The suggestion of an Investigation Board that crew should have probed some raw data bus via what is essentially a maintenance system, while airborne during an abnormal which affected the primary flight instruments, is bizarre.

vilas
27th Apr 2019, 19:00
The suggestion of an Investigation Board, that crew should have probed some raw data bus via what is essentially a maintenance system, in flight and during an abnormal that affected primary flight instruments, is bizarre.
Surely! I doubt any commercial aircraft has AoA displayed on the instrument panel. I think the investigation board was not briefed properly on the Nav ADR disagree procedure and function of the MCDU AoA recorded value. I hope next time they don't suggest some non standard CB reset. That will be a disaster.

dirk85
27th Apr 2019, 19:48
In my company we cannot access those pages as per our SOPs, unless instructed by engineers on the phone.

Denti
27th Apr 2019, 20:24
Surely! I doubt any commercial aircraft has AoA displayed on the instrument panel.

First of all, it was displayed on A320s in the low 100 MSNs, so there is actually an example of the type in question, although not on the primary displays, but rather as an additional instrument. And of course, the 737NG offered an AOA display for 15 years or so on the PFD as a customer option. Of course driven by the request of the military customers but also used by airlines including American Airlines. Not to mention, most, if not all civilian HUD installations display AOA as well.

sonicbum
27th Apr 2019, 22:07
First of all, it was displayed on A320s in the low 100 MSNs, so there is actually an example of the type in question, although not on the primary displays, but rather as an additional instrument.

AFAIK/remember on the A320 it used to be (prior to the BUSS) an option as well.

compressor stall
27th Apr 2019, 22:47
Aircraft is MSN 429.

novice110
28th Apr 2019, 01:16
Thanks for the info all.

The report goes into much detail, worth a read for beginners like me. I believe it infers the crew should have accessed this maintenance function, without training or procedures to follow. Can you imagine the results if crews started using such unapproved functions, at the expense of ECAM and A-N-C, in a time critical unreliable airspeed situation ?

krismiler
28th Apr 2019, 09:15
The Back Up Speed System is a huge improvement, just keep the needle in the green.

Check Airman
28th Apr 2019, 19:08
I don't think that anyone could reasonably expect a crew facing difficulty controlling a plane with unreliable airspeed to go digging to find AoA.

I agree with the above posters that it should be permanently displayed on the PFD.

Winnerhofer
28th Apr 2019, 21:19
AOA indicator as well HUD was standard on IT (Air Inter) A320 however GPWS was surprisingly NOT!

Vous savez que le BEA a recommandé dans son rapport sur le Rio-Paris « l’installation d’un indicateur d’incidence sur tous les avions de ligne »
Réaction des constructeurs : NADA !

Fursty Ferret
29th Apr 2019, 08:51
AoA is there if you want to use it, via HUD if fitted or on the PFD if you use TK/FPA.

Do you mean the bird/FPV? If everything is working it gives you an *approximation* of your AoA, but unless you know the angle of incidence it'll only ever be that: an approximation. Given that the FPV uses a combination of air data and inertial sources, I'd caution very strongly against referencing it for anything where you might have an unreliable air data situation. Even if you have the numerical value, it's not helpful unless you have a benchmark. I wouldn't go searching around for a small number in the corner of the PFD when the difference between stall and un-stalled is 1 degree or less at high levels.

What you could do is have a system that looks at the current AoA, and the stall AoA, and have a synthetic voice call out "STALL" if one exceeds the othe- oh, wait.

If you're in any doubt about the situation, and it's shouting "stall", then do the stall recovery procedure. Otherwise set pitch and power memory items and WAIT until the situation stabilises.

vilas
29th Apr 2019, 11:52
Not a fan of the BUSS, find it too sensitive, far prefer to set an attitude and power.
With all three ADRs off the Flt Ctls are in alternate law. There is no reason for the aircraft to be any more sensitive than it is supposed to be. Now in A350 Airbus has come out with alternate speed calculation and backup speed. They have quadruple ADR redundancy( B737MAX has zero) and alternate speed calculation using AOA, load factor and weight which is fed into the lift equation to get back up speed which is compared with ADR speed. If there's a discrepancy between ADR speed the system will generate a warning and automatically change to back up speed. In future A 320 and A330 will have option of this. So with UAS all that apilot does is say thank you and ask for a coffee.

Jonty
29th Apr 2019, 15:35
With all three ADRs off the Flt Ctls are in alternate law. There is no reason for the aircraft to be any more sensitive than it is supposed to be. Now in A350 Airbus has come out with alternate speed calculation and backup speed. They have quadruple ADR redundancy( B737MAX has zero) and alternate speed calculation using AOA, load factor and weight which is fed into the lift equation to get back up speed which is compared with ADR speed. If there's a discrepancy between ADR speed the system will generate a warning and automatically change to back up speed. In future A 320 and A330 will have option of this. So with UAS all that apilot does is say thank you and ask for a coffee.


Now that I like!

gearlever
29th Apr 2019, 16:12
With all three ADRs off the Flt Ctls are in alternate law. There is no reason for the aircraft to be any more sensitive than it is supposed to be. Now in A350 Airbus has come out with alternate speed calculation and backup speed. They have quadruple ADR redundancy( B737MAX has zero) and alternate speed calculation using AOA, load factor and weight which is fed into the lift equation to get back up speed which is compared with ADR speed. If there's a discrepancy between ADR speed the system will generate a warning and automatically change to back up speed. In future A 320 and A330 will have option of this. So with UAS all that apilot does is say thank you and ask for a coffee.

Love your last sentence:O

sonicbum
29th Apr 2019, 17:49
By the way I hope there will still be airlines where You don't have to pay for that coffee (ok I shut up) ;-)