A Level 1 AOA clarification

G.R. Patterson III wrote:
Rama, in my post, I forgot that at a higher airspeed, the plane is likely
to be
climbing, therefore the relative wind will be coming from above. You will
reach
the same angle of attack at a steeper pitch angle at higher airspeeds.

What?

Hilton

Greg Esres wrote:
Stall/spin is a leading cause of death among GA pilots and
passengers.

Caused by the pilot not paying attention. Will having another
instrument that he's not paying attention to really help?

Yes, *if* the AOA is effectively communicated to the pilot. I'm not
suggesting we just stick a few LEDs on the panel. I would want to see some
audio piped into the headset, and/or a stick-shaker etc. I find it amazing
that everyone jumps all over this new GPS whizbang stuff - is it going to
increase or decrease the accident rate? I don't know. But a simple AOA
detector that will directly reduce the number of accidents and fatalities
goes completely ignored.


Best glide (potential emergency situation) is determined by AOA.

A few knots either way isn't going to make much difference. Plus, how
often is maximum glide range critical in an engine out situation?

Take a look at the fuel exhaustion/starvation accidents - they always seem
to 'land' a mile or two from their destination.



How
closely is the pilot really maintaining one airspeed (or AOA) during
an emergency?

I don't know - I haven't seen any research on this one.


Put an AOA sensor on GA planes with a hand that smacks the pilot on
the head

Some studies I've seen have shown that pilots are often oblivious to
warning horns and lights, though stick shakers are effective.

Lights are useless - the Arrow's stall light is embarrasing. Stall
'buzzers' are OK. So, let's figure out something new, or how about stick
shakers on GA aircraft. Just throwing up our arms while people continue to
die is not good enough.


My prediction: put an AOA indicator on every airplane in the fleet
and you won't see much change in the accident rate due to stall spin.

I completely disagree (if done correctly - see above).

Hilton

Well, not to dispute the thrust of your argument, but your statistics
are wrong... CFIT is the leading cause of injury and death in GA...
Stall/spin crashes in vfr flight are down the list a ways..

Now, if the pilot is incapable of noticing the air speed indicator well
down into the white arc, or is incapable of noticing that the nose is
well up, or that he is pulling G's while stomping top rudder, what
makes us suspect that he will notice the AOA needle in the red?

Denny

Peter Duniho wrote:

"CV" wrote in message
...

By reducing the AOA actually, which happens as a consequence of
increasing airspeed. But see below also.

No. Increased airspeed happens as a result of reduced angle of attack, not
the other way around.

Be that as it may, flying faster allows us to use a smaller AOA,
which is what prevents the stall.

We can stall at any speed, and at any attitude, but it always
happens at the same (or very close to the same) AOA.

CV

Yes, *if* the AOA is effectively communicated to the pilot.

You're really just talking about a more effective stall warning
system. Fine.

But a simple AOA detector that will directly reduce

Hypothesis. Skydivers point out that in spite of all the new safety
equipment they have these days, the fatality rate stays about the
same. People will always push the limits to achieve what they
consider an "acceptable" risk.

Consider that the unstallable airplanes such as the Ercoupe didn't
show any improvement in accident rates.

Just throwing up our arms while people continue to
die is not good enough.

The sure-fire way to reduce the fatality rate is to add ballistic
parachutes to our aircraft....no, wait, that hasn't worked either.
;-)

I don't know the solution to the problem. It may be an unavoidable
aspect of our freedom to fly.

Andrew is stating that the angle of attack at which this occurs is
the same regardless of airspeed. I believe he is incorrect in this

Andrew is 100% correct on this.

my aircraft will stall at a much lower angle of attack at 50 mph
than at 60 mph, and I've never been brave enough

That sentence doesn't make any sense at all. You may be confusing
pitch angle with angle of attack.

The only means you have of determining your AOA is your airspeed
indicator. At 50 mph, you are at a higher AOA than at 60 mph.

You will reach the same angle of attack at a steeper pitch angle at
higher airspeeds.

Same AOA = Same airspeed.

You will reach the same angle of attack at a steeper
pitch angle at higher airspeeds.

What?

Hilton

He's saying that, by definition, the AOA is the wing's angle to the
*relative* airflow. Pitch is relative only to the ground, and really has no
bearing on this entire discussion.

-Frank

Frankster wrote:
You will reach the same angle of attack at a steeper
pitch angle at higher airspeeds.

What?

Hilton

He's saying that, by definition, the AOA is the wing's angle to the
*relative* airflow. Pitch is relative only to the ground, and really has
no
bearing on this entire discussion.

Frank,

The sentence above read: "at a higher airspeed, the plane is likely to be
climbing, therefore the relative wind will be coming from above."

I don't understand the first part (higher speed and climbing?) and the
second part is wrong.

Hilton

Greg Esres wrote:
Yes, *if* the AOA is effectively communicated to the pilot.

You're really just talking about a more effective stall warning
system. Fine.

Both really (indicator and stall warning), but yes, a more effective stall
warning system would literally be the life saver.


But a simple AOA detector that will directly reduce

Hypothesis.

Are you contradicting your previous comment: "Some studies I've seen have
shown that pilots are often oblivious to warning horns and lights, though
stick shakers are effective."?


The sure-fire way to reduce the fatality rate is to add ballistic
parachutes to our aircraft....no, wait, that hasn't worked either. ;-)

I see the parachute guys got a mention on CNN. I wonder if/when the
research will start about the effect they have on a pilot's thinking,
decision making, and risk assesment. I know one was 'fired' when an aileron
became detached - was the plane really uncontrollable? Maybe, I'm not going
to doubt the pilot's remarks. But what about the other ones, and the
accidents where a pilot *perhaps* fly into 'unsuitable' conditions. BTW:
I'm also writing this in future tense.


I don't know the solution to the problem. It may be an unavoidable
aspect of our freedom to fly.

I'd like to think it's a solvable problem, or at least reducable.

Hilton

Denny wrote:
Well, not to dispute the thrust of your argument, but your statistics
are wrong... CFIT is the leading cause of injury and death in GA...
Stall/spin crashes in vfr flight are down the list a ways..

You got a source for these assertions?

Hilton