AOA Probe Failure

[455 Bravo Uniform]

Is a standalone AOA probe susceptible to plugging by bug guts?

If so, what’s the failure mode? Reading high, low, or depending on which hole is plugged?

Good to cross reference the ASI and stall warning, but will always be outside the envelope- stall horn blaring and ASI reading low and inaccurate due to angle.

Just wondering, not trying to start an argument. I’d like to install one eventually.

 

[weirdjim]

Right now Boeing is trying to figure out an answer to that question.

Jim

 

[Sinistar]

When reading about the 737 Max 8 AOA sensor problems, the FAA listed 2 of 3 companies with a notable amount of failures. They didn't list the 3rd but it's something like Thane or Thale?

It seems that the failures are more related to precip (rain, ice, etc) than bugs.

 

[Sinistar]

...oops last post really didn't help any...is the hole bigger than the pitot tube inlet? Maybe bugs are more likely to enter when parked than in flight...do they have covers like pitot tubes?

 

[Ravioli]

If you've got airspeed indication and a stall warning horn, what exactly do you need AoA for?

I mean really, the plane is already going to be telling you what's going on if your stalling, isn't it?

 

[455 Bravo Uniform]

If you've got airspeed indication and a stall warning horn, what exactly do you need AoA for?

I mean really, the plane is already going to be telling you what's going on if your stalling, isn't it?

My stall horn is only on or off (at 44kts indicated), can’t tell how close to the stall I am once it turns on, then I have the ASI that I can use, but accuracy around 40kts is not great. Stall at 20-40 deg flaps is 35kts indicated. I’d just like to experiment with an AOA, with its precision, plus I like that I can have the sight on the glareshield (like @motoadve). My short field landings are not short enough (I’m greedy). Dumb? Maybe.

 

[Fancy]

If you've got airspeed indication and a stall warning horn, what exactly do you need AoA for?

I mean really, the plane is already going to be telling you what's going on if your stalling, isn't it?

You can use AOA for all sorts of stuff!! Max range, max endurance, min radius, max turn rate, best glide, best climb, and magnitude of control input to “break” a stall to name a few off the top of my head. Aoa flying needs to be trained to by someone that know what they’re doing however. But...assuming an accurate indication, aoa tells you more about the aerodynamic state of an aircraft than any other instrument.

 

[WannFly]

The hole is about the same as pitot. Don’t know failure mode, haven’t had a pitot or AOA probe blocked...yet.



Might have just jinxed it

 

[Sinistar]

@WannFly - does your AOA have small cover that you put on when parked?

 

[WannFly]

@WannFly - does your AOA have small cover that you put on when parked?

I have been thinking about putting that cover on in summer for 2 summers now

 

[Sinistar]

Isn't 2 summers like as long as you've owned your plane

 

[455 Bravo Uniform]

I guess it’d be easy enough to test. Once with one hole covered with tape, next with the other (then both, if need be).

 

[WannFly]

I guess it’d be easy enough to test. Once with one hole covered with tape, next with the other (then both, if need be).

As tempting as it sounds, I am gonna pass

 

[GRG55]

Isn't 2 summers like as long as you've owned your plane

"Two summers" is about a total of four weeks in North Dakota. I am certain he's owned the plane longer than that.

 

[455 Bravo Uniform]

As tempting as it sounds, I am gonna pass

Why not? As long as you fly with air-speed during the check?

 

[Hank S]

Right now Boeing is trying to figure out an answer to that question.

Jim

So is Cirrus, there's an Emergency AD out on the AoA sensor for their fsncy new jet. "Before Next Flight", even . . . .

Someone during assembly left loctite out of two set screws, and maybe didn't torque them right (or maybe they are loose due to lack of loctite). Results in undesired / unneeded / uncommanded nose down inputs with stall horn, stick shaker, etc.

Sounds kinda familiar, doesn't it?

 

[Sinistar]

As tempting as it sounds, I am gonna pass

Why not?

I'm with @455 Bravo Uniform on this one, he will learn how it fails in all cases and it's my understanding that these AOA indicators that you 2 are using are not tied into any other systems right?

 

[WannFly]

Why not?

I'm with @455 Bravo Uniform on this one, he will learn how it fails in all cases and it's my understanding that these AOA indicators that you 2 are using are not tied into any other systems right?

Yah it’s not tied to anything. I was referring to blocking both the probes and fly. Good skill to have but haven’t done a airspeed INOP flight since primary

 

[455 Bravo Uniform]

Yah it’s not tied to anything. I was referring to blocking both the probes and fly. Good skill to have but haven’t done a airspeed INOP flight since primary

Just to be clear, when I said “both”, I meant both holes of the AOA probe. ASI would remain fully functional.

 

[WannFly]

Just to be clear, when I said “both”, I meant both holes of the AOA probe. ASI would remain fully functional.

Ok. Yah that I can fly and report back next time I am up