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-   -   E170/190 Angle of Attack (https://www.pprune.org/tech-log/596174-e170-190-angle-attack.html)

Check Airman 22nd Jun 2017 04:29

E170/190 Angle of Attack
 
Hi all,

The E170/E190 series doesn't have angle of attack vanes. How does it sense AoA?

Chesty Morgan 22nd Jun 2017 08:19

Smart probes.
http://utcaerospacesystems.com/cap/s...%20Systems.pdf

Amadis of Gaul 22nd Jun 2017 14:33

PFM principle.

Piltdown Man 23rd Jun 2017 09:59

And now for the real killer. These aircraft use the "Smart" data to drive the flight path vector. The flight path vector cannot be removed from the PFD. After a few hundred hours you forget the actual pitch associated with any aspect of your flight. You and the autopilot merely drive the FPV onto the flight path target. What could possibly go wrong? Erm... birdstrike (bee strike), pitot heat, writing, leak, system failure etc. followed by one EICAS message and a double ding you now are flying with invalid FPV data. You have three systems and one or two of them are telling lies. You can't get rid of the FPV and possibly both sides have different FPV values (or both are wrong, both are right or No. 3 is invalid, but it's not displayed) and the pitch you need is... Oh, and you need to kill the auto throttle before it kills you as a well.

I notice they don't crow about how simple it is to deal with system failures.

gearlever 23rd Jun 2017 11:15

I had a look on smart probes website, but it still puzzles me how they derive AOA from a probe what looks like a pitot probe.

Check Airman 24th Jun 2017 06:04


Originally Posted by Chesty Morgan (Post 9809179)

Thanks for the link. I think it sent me in the right direction.

Check Airman 24th Jun 2017 06:05


Originally Posted by gearlever (Post 9810267)
I had a look on smart probes website, but it still puzzles me how they derive AOA from a probe what looks like a pitot probe.

Apparently there's another hole underneath the dynamic pressure port that is used to drive AoA data.

Check Airman 24th Jun 2017 06:07


Originally Posted by Piltdown Man (Post 9810206)
And now for the real killer. These aircraft use the "Smart" data to drive the flight path vector. The flight path vector cannot be removed from the PFD. After a few hundred hours you forget the actual pitch associated with any aspect of your flight. You and the autopilot merely drive the FPV onto the flight path target. What could possibly go wrong? Erm... birdstrike (bee strike), pitot heat, writing, leak, system failure etc. followed by one EICAS message and a double ding you now are flying with invalid FPV data. You have three systems and one or two of them are telling lies. You can't get rid of the FPV and possibly both sides have different FPV values (or both are wrong, both are right or No. 3 is invalid, but it's not displayed) and the pitch you need is... Oh, and you need to kill the auto throttle before it kills you as a well.

I notice they don't crow about how simple it is to deal with system failures.

What's worse is that the FPV is in front of the crntre dot of the miniature airplane, and thus partially obscures the attitude indication. A truly horrible design.

FE Hoppy 25th Jun 2017 00:18

It's a flight path angle on the EJet PFD. Not a Vector.

And the pitch attitudes are in the QRH

Amadis of Gaul 25th Jun 2017 00:24

Those who need the QRH to know their pitch attitudes have bigger problems than an FPA indication.

Check Airman 25th Jun 2017 06:37

On the 190, the design philosophy seems to have been that attitude is a secondary parameter, as the FD only shows the flight path you need, and not the pitch. It's a most asinine system.

simmple 25th Jun 2017 09:00

On the 190, the design philosophy seems to have been that attitude is a secondary parameter

Have things changed in the magenta following world that pilots or should they now be called aircraft operators no longer fly pitch and power= performance, they just blindly follow a vector!

Check Airman 25th Jun 2017 12:20

Perhaps at the Embraer factory. Thankfully Boeing and Airbus still know what they're doing.

Chesty Morgan 25th Jun 2017 16:49


Originally Posted by Amadis of Gaul (Post 9811580)
Those who need the QRH to know their pitch attitudes have bigger problems than an FPA indication.

Where else are you going to get them?

Amadis of Gaul 25th Jun 2017 17:40

Experience, my brother, experience.

Amadis of Gaul 25th Jun 2017 17:41


Originally Posted by simmple (Post 9811758)
Have things changed in the magenta following world that or should they now be called operators no longer fly pitch and power= performance, they just blindly follow a vector!

And that's not even the worst of it, I fear...

Chesty Morgan 25th Jun 2017 17:52

So you can remember ALL combinations of pitch and power for every airspeed, weight, altitude, aircraft configuration, climb, cruise, descent and holding?

Because at the last count there are 115 different combinations in my QRH with plenty of interpolation available.

FE Hoppy 25th Jun 2017 18:06

And for those banging on, the CSeries has FPV as primary too.
Like the Ejet, the pitch indication is always in view and the same style pitch tables are available in the QRH.

Welcome to the 21st century ;-) no bits of string tied to the windscreen required.

Amadis of Gaul 25th Jun 2017 20:00


Originally Posted by Chesty Morgan (Post 9812127)
So you can remember ALL combinations of pitch and power for every airspeed, weight, altitude, aircraft configuration, climb, cruise, descent and holding?

Because at the last count there are 115 different combinations in my QRH with plenty of interpolation available.

I don't need to remember all of them, TLAR principle does wonders. Airmanship is an amazing thing.

Chesty Morgan 25th Jun 2017 20:34

No you don't because some clever chap has published then for you.

The correct use of airmanship is an amazing thing. The incorrect use of ego isn't.


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