Proposed Advisory Circular For Stall And Stick Pusher Training

nosehair said:
WoW! I am dumbfounded! Seriously! :eek:

All these years I've been flying and teaching small prop airplanes, I have always assumed that big expensive aircraft all had AoA indicators. How can this be?
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Indicators no, sensors yes.
 
jtrain609 said:
You guys don't have AOA information being fed into the low speed awareness on the airspeed tape?
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We have that, yes. Both maneuvering buffet margin info and the checkerboard shaker zone (along with a PLI). I guess I was thinking about an actual gauge showing AoA in degrees. :)

Sometimes I wish we just had the fast/slow indicator on the ADI; heavy departures with a low-level turn get you pretty damn close to that lower tape and low-speed buffet! :eek:
 
dasleben said:
Indicators no, sensors yes.
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Sensors? Do you mean information that has to be de-coded, edited, and analyzed, like an airspeed indicator has to be?
I have always thought that the AoA indicator was the most efficient way to fly. To fly specific AoAs for T.O.s, climbs, cruises, and approaches to get the best lift vs. drag, so I assumed these billion dollar airplanes would be flying that way.

Seems from the bits of chatter here that these 'sensors' are also subject to pilot interpretation, like the simple airspeed indicator.
 
nosehair said:
Sensors? Do you mean information that has to be de-coded, edited, and analyzed, like an airspeed indicator has to be?
I have always thought that the AoA indicator was the most efficient way to fly. To fly specific AoAs for T.O.s, climbs, cruises, and approaches to get the best lift vs. drag, so I assumed these billion dollar airplanes would be flying that way.

Seems from the bits of chatter here that these 'sensors' are also subject to pilot interpretation, like the simple airspeed indicator.
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I have no idea about all of that, but the operating weight envelope on many aircraft is wide enough that a specific AoA for various phases of flight probably wouldn't work too well. Our normal operating speeds for climb/cruise/descent/approach are based on flap maneuvering speeds and cost index (takes data from the jet and creates a best economy profile).
 
nosehair said:
Sensors? Do you mean information that has to be de-coded, edited, and analyzed, like an airspeed indicator has to be?
I have always thought that the AoA indicator was the most efficient way to fly. To fly specific AoAs for T.O.s, climbs, cruises, and approaches to get the best lift vs. drag, so I assumed these billion dollar airplanes would be flying that way.

Seems from the bits of chatter here that these 'sensors' are also subject to pilot interpretation, like the simple airspeed indicator.
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Not exactly.

It's just that it's associated with low speed awareness, so you don't get the data until you're moving fairly slow to begin with. All of our low speed data (speed tape data and PLI's) come off of the AOA indicators. So no, you don't always have a direct view of what your AOA is, but yes, you kind of do. The colors that the PLI change to as associated with being within so many degrees of stall based on AOA.
 
dasleben said:
I have no idea about all of that, but the operating weight envelope on many aircraft is wide enough that a specific AoA for various phases of flight probably wouldn't work too well. Our normal operating speeds for climb/cruise/descent/approach are based on flap maneuvering speeds and cost index (takes data from the jet and creates a best economy profile).
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Actually, the wide operating weight is exactly why flying AoA would work better. The AoA is constant for the given configuration. The airspeed changes to be able to maintain that AoA. We need airspeed for traffic separation, and this is likely why we use it instead of AoA, plus the fact that it is a legacy method so most are already familiar with it.
 
seagull said:
The airspeed changes to be able to maintain that AoA.
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I think we're on the same page, but we're saying it backwards to one another. The way I'm thinking of the scenario, the AoA would have to change in order to maintain a constant airspeed, which is why it's best to think in terms of airspeed for normal operations. A constant AoA would, as you said, result in different speeds.
 
However, the main issue is performance. We do not maintain a constant airspeed, it varies with weight. My airplane varies from 140-167 kts depending on weight.
 
AoA would allow for L/Dmax for climb, cruise and descent. The use of a constant speed is why we have varying amounts of distance we need to lose altitude with weight changes, as we vary from L/Dmax. ATC likes airspeed, but there is no reason that we could not utilize AoA for approach and have it available at other times as well.
 
seagull said:
However, the main issue is performance. We do not maintain a constant airspeed, it varies with weight. My airplane varies from 140-167 kts depending on weight.
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So does mine. :)

I'm thinking in terms of terminal speed assignments, mach number technique, etc. I agree that approach, climb, and to some extent, cruise, would best utilize AoA.
 
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