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  #21  
Old 01-06-2012, 09:20 AM
sailvi767 sailvi767 is offline
 
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AOA is not a requirement in any aircraft. It is however I think one of the biggest bang for the buck safety items you can install. It accomplishes several things at a modest cost. It gives you the best stall warning available. It also gives you a back up AS indicator. If your running a modern EFIS and have AOA installed in a isolated system you don't need another ASI.
The stall/spin accident has always been one of the largest killers in general aviation. I know most aircraft talk to a pilot and give many cues. Most of us would like to believe we will always hear the aircraft talking to us. The facts however support a quite different reality. Distractions and other things occur that can cause even the most experienced pilots to miss critical warnings. Almost every accident is a chain of events. AOA is a great tool to break that chain. Yes you might be the pilot who can fly with 100 percent precision and feel every subtle cue the airframe gives off. I am certainly not that pilot.

Consider a pilot flying his RV8. He is taking a cross country flight with a heavy friend in the back seat and lots of bags. He is near max gross weight where he has rarely flown the aircraft. Coming into the pattern his radio is acting up and he is try to isolate the static. There is moderate turbulence below 2000 feet. Turning base he is unaware there is a 15 knot decreasing performance shear at 500 feet. Another pilot who he did not hear on the radio is flying a non standard right hand pattern into the field. As he is rolling out on final he spots the other aircraft and tries to go around rolling into a steeper bank angle and pitching up as the shear impacts the very heavy aircraft. Is this pilot who always recognized the cues to a stall going to pick them up in this situation. Is he going to pick them out while focusing on the other aircraft with the airframe in moderate turbulence at a weight he does not normally fly at?
I know all that sounds like too many events in one approach but as a trained accident investigator it mirrors so many accidents. There is always a unlikely confluence of events. The above is actually from memory of a accident we studied many years ago.
This thread kind of reminds me of TCAS for part 121 aircraft when it first came out. Many senior captains did not believe in it. I flew with one captain he would not even turn it on. He had lots of reasons why. 5 years later I flew with that same captain. He stuck out in my mind because he had refused to turn on the TCAS. We picked up a aicraft in DFW where the TCAS system was on maintenance carry over as being inop. It was legal to fly without it for a certain number of days before it had to be repaired. The same captain who once refused to turn it on now refused to take the aircraft even though it was legal with it broken. I asked him about his change of heart and he replied "I may be dumb but I am trainable".
AOA is simply another tool like TCAS or TIS. Its a great tool to have and might just one day be the one thing that breaks the link in a chain of events leading to a accident. Its also a excellent training aide. You certainly don't need it and the majority of aircraft have flown without it since 1903. For the price however I think its a excellent cost benefit item to have in your aircraft.

George
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  #22  
Old 01-06-2012, 09:56 AM
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Ron Lee Ron Lee is offline
 
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Quote:
Originally Posted by pvalovich View Post
As a former Navy carrier guy, I thought installing an AOA (AFS Pro) system on my -8A would be really cool. However, after 130+ hours I stil find that I never use it.

Have any of you more experienced RV'rs found more AOA utility?
I do not have any stall warning system yet having one "may" help reduce stall/spin fatalities. As mentioned in RVFlightSafety.org, a system that has an aural element may be better than just relying upon a visual indicator in cases where it may prevent a fatality.
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  #23  
Old 01-06-2012, 09:59 AM
luddite42 luddite42 is offline
 
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Quote:
Originally Posted by sailvi767 View Post
Consider a pilot flying his RV8. He is taking a cross country flight with a heavy friend in the back seat and lots of bags. He is near max gross weight where he has rarely flown the aircraft. Coming into the pattern his radio is acting up and he is try to isolate the static. There is moderate turbulence below 2000 feet. Turning base he is unaware there is a 15 knot decreasing performance shear at 500 feet. Another pilot who he did not hear on the radio is flying a non standard right hand pattern into the field. As he is rolling out on final he spots the other aircraft and tries to go around rolling into a steeper bank angle and pitching up as the shear impacts the very heavy aircraft. Is this pilot who always recognized the cues to a stall going to pick them up in this situation. Is he going to pick them out while focusing on the other aircraft with the airframe in moderate turbulence at a weight he does not normally fly at?
At this point would he have actually picked out the (visual only) status of the little AOA indicator on the panel?
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  #24  
Old 01-06-2012, 10:33 AM
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Rick6a Rick6a is offline
 
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Quote:
Originally Posted by luddite42 View Post
At this point would he have actually picked out the (visual only) status of the little AOA indicator on the panel?
Nice try. I'd say he would have a reasonable expectation of picking out the (visual only) status of the little AOA indicator.

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  #25  
Old 01-06-2012, 10:48 AM
luddite42 luddite42 is offline
 
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Quote:
Originally Posted by Rick6a View Post
Nice try. I'd say he would have a reasonable expectation of picking out the (visual only) status of the little AOA indicator.

I see a huge attitude indicator and a small AOA indicator.

Previous poster's scenario led up to the accident pilot maneuvering "while focusing on the other aircraft". I take that to mean his head was not on the panel, AOA or no AOA. All I'm saying is that if folks are distracted enough to miss the cues that the ASI, bank angle, stick pressure, airframe buffet, wind noise, etc. are making, how do we arrive at the idea that AOA will be the one thing they will finally take note of? Yes, it's one more tool that could help, and I have NO problem with that. I just disagree a bit about how strongly some feel that it's that likely to be the thing that breaks the accident chain. To see the AOA, don't you have to deliberately look at it? Aural indicator is another issue. If you deliberately look at it (before you stall, anyway), doesn't that mean that you have some concern with, and are actually thinking about what your AOA might be? Seems that part would be the missing link in the chain of most accidents, and if present, would likely cause the pilot to adjust his AOA with or without the actual visual AOA indicator.

I totally get how AOA can help fly precision approaches, but if we're talking about it being some sort of "dummy light" the pilot sees just before he snaps the plane into the ground on base-to-final, wouldn't a standard stall-warning horn found on every TC'd plane take care of this, only better, since it's aural?

Last edited by luddite42 : 01-06-2012 at 10:53 AM.
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  #26  
Old 01-06-2012, 11:32 AM
sailvi767 sailvi767 is offline
 
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Quote:
Originally Posted by luddite42 View Post
At this point would he have actually picked out the (visual only) status of the little AOA indicator on the panel?

No he would not. However the system should have a aural component. Mine would be screaming "Angle Angle Push". Without a aural component I agree that its not valuable in the above situation.
It could however have caused him to bump his speed a bit on the base leg by giving him cues as to how heavy the aircraft was when he did a normal crosscheck so he might have been carrying a few more knots. That speed bump might have made the difference. Normally a pilot would have bumped his approach speed for weight and conditions but again we all get distracted. The AOA crosscheck can be a good reminder.

Last edited by sailvi767 : 01-06-2012 at 11:34 AM.
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  #27  
Old 01-06-2012, 11:47 AM
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Toobuilder Toobuilder is offline
 
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Plenty of Vietnam era combat studies proves that humans have an amazing ability to tune out or otherwise ignore aural warnings - especially if those noises are competing for "bandwidth" in the brain of a pilot who is dealing with (seemingly) higher priority activity.

Heck, why would a pilot respond to "angle, angle push" any more than a gear warning horn?
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Last edited by Toobuilder : 01-06-2012 at 11:51 AM.
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  #28  
Old 01-06-2012, 11:47 AM
RVnoob RVnoob is offline
 
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Quote:
Originally Posted by sailvi767 View Post
No he would not. However the system should have a aural component. Mine would be screaming "Angle Angle Push". Without a aural component I agree that its not valuable in the above situation.
It could however have caused him to bump his speed a bit on the base leg by giving him cues as to how heavy the aircraft was when he did a normal crosscheck so he might have been carrying a few more knots. That speed bump might have made the difference. Normally a pilot would have bumped his approach speed for weight and conditions but again we all get distracted. The AOA crosscheck can be a good reminder.
One of these days,
in the not too distance future,
the AOA will push the stick for you as well...
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  #29  
Old 01-06-2012, 02:17 PM
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flyingbeaver26 flyingbeaver26 is offline
 
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I am installing a G3X dual sreen set-up. I was hoping that Garmin would add a derived AOA feature much like GRT did. I have yet to hear anything about this feature being added.
So if Garmin has no intent to provide a derived AOA, then my optins are Advanced, Dynon, or ???. I personally would prefer something that provides an audible warning. So that rules out the steam gauge versions. Does anybosy have a list of vendors for this type of device?

Thanks,
Brad
-8, panel wiring/fiberglass tips
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  #30  
Old 01-06-2012, 02:43 PM
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panhandler1956 panhandler1956 is offline
 
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This has been an interesting dialogue. I have been on the fence about an AOA since I started building my -8. Now that I have it flying, I have for the most part dismissed the idea, but this discussion raises some great points.

As for audio, I would think it would be a fairly benign software code change to provide audio alerts for the AOAs that are integral to the EFIS (AFS, GRT, etc).

Right now all my spare change is paying for gas so I'll have to wait in any event.
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