E170/190 Angle of Attack
 

Hi all,

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

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

PFM principle.

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.

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.

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

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

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.

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

And the pitch attitudes are in the QRH

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

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.

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!

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

Where else are you going to get them?

Experience, my brother, experience.

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

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.

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.

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

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.

What ego, O Chesty of My Soul? Airplanes flew long before the 170/190 and will long after. Physics haven't changed, aerodynamics haven't changed.

Outta curiosity, what do you plan on doing one fine day when the QRH is not available (for whatever reason)? Are you up the proverbial small river without the similarly proverbial rowing device or what?

It's not too difficult to fly once you have realised what is going on. The difficult bit is working out which system/s are correct and which are wrong.

The ego part of thinking what you think looks about right is better than flying the actual pitch and attitude you need to achieve the performance you need.

The chances of not having either of the two electronic QRHs or the two paper QRHs available when we need them is minute but I guess that's why we also have a broad stroke memory item. That would also be the time to employ airmanship.

Surely you're not suggesting that one look up the pitch from a 115 cell table every time time he changes the attitude. Then what other option is there but to TLAR it first, and then fine-tune based on the performance instruments?

No.........

That's exactly what he's suggesting.

Then what?

I refuse to believe such an absurdity unless he says it explicitly. Principle of charity, and all that.

He HAS said it explicitly. In fact, he labeled anything else "excessive ego".

No I haven't.

So what is it?

What is what?

What are you suggesting regarding the proper setting of pitch attitude?

I'm suggesting that to achieve the performance you require then you fly the correct pitch and power settings.

It might help you to understand that, in normal circumstances, we don't fly pitch and power.

That sounds reasonable. But the discussion was already at a point beyond that. So how do you know the correct pitch and power settings to fly?

No, the discussion was at the 'I know better so I'll make it up' point.

I don't. No, I can't know them all. That's why the same nice man who Amadis is going to ignore has provided them for me.

I guess I wasn't as clear as I thought. I didn't mean knowing them as in being able to recite them to me on the forum, but rather knowing them as in applying them in the cockpit. (Flight director aside, of course.) So, while flying, how do you set the correct pitch and power?

Like I said, they're all in the QRH.

I don't understand. What do you do with this information? When I said "Surely you're not suggesting that one look up the pitch from a 115 cell table every time time he changes the attitude" you flatly said "no." So you don't look it up when you're flying, you don't memorize them all (as you've said a few times, it's impossible), then what do you do?

I use it when I need it.

We don't fly pitch or power (no airliner I've ever flown requires it), in normal circumstances, so there's no need to refer to any table, in normal circumstances.

You've said what you don't do (many times over), but my question is, what do you do?