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Old 04-10-2015, 09:09 AM
Canadian_JOY Canadian_JOY is offline
Join Date: Aug 2007
Location: Ontario, Canada
Posts: 2,243
Default Aspen AOA & GRT AOA

Not sure this is the right place for this thread - mods, please feel free to move if you feel there's a better spot for it.

At the current AEA convention Aspen Avionics has announced the availability of AOA as a software upgrade to their existing display products.

This announcement tweaked my curiosity because it appears that Aspen is just now releasing a "derived AOA" product similar to the one GRT has had available in their EFIS products for some number of years.

Not having flown a "derived AOA" system myself, I've been wondering how they stack up against "measured AOA" systems. Since I have a GRT EFIS in the panel already I'm also wondering if it's a worthwhile investment in space on the screen to display the derived AOA. In other words, is this "derived AOA" good enough to add a real benefit to flight safety?

I know many of the crew here, particularly the former military pilots who sprouted their wings in AOA-equipped cockpits, are spring-loaded to say any AOA is better than no AOA. I'd really like to hear feedback from those who have used "derived AOA" as I'm already convinced of the advantages of having some form of AOA indication in the cockpit.
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Old 04-10-2015, 10:24 AM
David Paule David Paule is offline
Join Date: Dec 2009
Location: Boulder, CO
Posts: 4,335

At the risk of being the only person in this neck of the woods with this opinion, note that a stall switch such as Van's, when properly adjusted, gives notice of a single-point angle of attack, typically before stalling.

So if the primary use of AOA is stall prevention, that's sufficient.

Real full-scale AOA can (and should) be used for adjusting the approach or climb angle, in my opinion.

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Old 04-10-2015, 11:13 AM
RVbySDI's Avatar
RVbySDI RVbySDI is offline
Join Date: May 2005
Location: Tuttle, Oklahoma
Posts: 2,563

I have been using the GRT Angle of Attack display setting since they released it. As far as the idea of it taking up screen real estate, I would say that is not an issue. It is in the upper left hand area of the display. It is not there all of the time. It only displays once you reach the parameters that trigger a warning. Otherwise, during normal flight parameters nothing is there.

It is a helpful tool to have but I do not rely on it exclusively. In fact, due to the fact that it is down on the EFIS screen and I am a VFR pilot who spends most of my time looking out the window while flying, it has limited functionality in the most useful times (i.e. during base/final approaches to landing). I have talked with Greg over the span of several years while at Oshkosh about allowing for audio alerts for the Angle of Attach. When GRT released their latest version for their EFIS software that incorporated audio alerts I was very excited, hoping that my years of discussions with Greg had finally paid off. Alas, suffice it to say I was extremely disappointing when I loaded the new audio alerts to find out there were none for the Angle of Attack functionality. I still do not think any AoA system should be in place without some form of audio alert when the goal is to keep your eyes out the window. Yes, I fully understand about IFR flying in which one is staring at an EFIS screen while flying. That makes sense to have a visual only alert on the screen. In the VFR world this leaves the pilot lacking in functionality however. I am still hopeful GRT will release audio alert capabilities with their AoA but considering I have had multiple conversations over multiple years with them at their booth during Oshkosh and there still is nothing new with this, I can only continue to hope that eventually GRT will release an update with this capability.

Live Long And Prosper! 🖖🏻
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Old 04-10-2015, 11:41 AM
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Bill Boyd Bill Boyd is offline
Join Date: Sep 2006
Location: Landing field "12VA"
Posts: 1,507
Default Hear, hear!

I am not a programmer, but it seems like implementation of this announcement function, as an add-on to what's now there, would be child's play, in comparison to having developed the HX EFIS to its present state.

Let's hope. I'm sure Greg is or will be aware of the desire for this.

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Old 04-10-2015, 12:57 PM
Tony Rome Tony Rome is offline
Join Date: Apr 2012
Location: Illinois
Posts: 38
Default AOA Alerts

Noticed this reply on the GRT forum:

"Re: V 7 ... audio alerts ...

Postby GRT_Jeff ? Fri Apr 03, 2015 11:14 pm

Most alerts play only once when the condition is first met. There's a warning tone, a caution tone, and an advisory/chime tone. Most alarms are just the chime. A handful of special alerts are not related to alarms. AoA has a repeating tone that repeats faster the closer you are to stall. Custom voice alerts can be added to any alarm that has an alarm identifier, but those haven't been documented yet. The only speed alert is for exceeding Vne.

Here's the list of special alerts:
Min Oil Pressure
Min Fuel Pressure
AoA tone near stall, repeats more frequently closer to stall
Obstacle alarm
New traffic within alert criteria
Autopilot Disconnect
Max Oil Temperature
Low/High Voltage
Max Fuel Flow
Vne Exceeded
Trim alert (from GRT pitch servo) repeats every 30 seconds
SAP height above runway at 500, 200, and 100 feet
Minimums if decision altitude is set
Approaching minimums when 200 feet above decision altitude
Waypoint sequence"

Sounds like it is already being done.
Good job GRT!

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Old 04-10-2015, 01:41 PM
Canadian_JOY Canadian_JOY is offline
Join Date: Aug 2007
Location: Ontario, Canada
Posts: 2,243

Alas, audio alerts are only available on HX / HXr, not for us legacy HS/WS users (or so say the release notes... I would LOVE to be proven wrong on this point!)
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Old 04-10-2015, 01:43 PM
Bill Boyd's Avatar
Bill Boyd Bill Boyd is offline
Join Date: Sep 2006
Location: Landing field "12VA"
Posts: 1,507
Default Indeed,

Good job on the software updates.

This will make lots of us glad we pigtailed EFIS D-sub pin B-24, or that we own a wire spoon

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Old 04-10-2015, 09:49 PM
jclark jclark is offline
Join Date: Jan 2005
Location: Columbia, SC
Posts: 804
Default Not just HX/HXr

Originally Posted by Canadian_JOY View Post
Alas, audio alerts are only available on HX / HXr, not for us legacy HS/WS users (or so say the release notes... I would LOVE to be proven wrong on this point!)
Audio alerts have been available for a while on the HX **AND** the SX Series.

And it works with the angle of attack.

Varying tones depending upon where you are in AoA.

I suspect that the WS systems have neither the hardware horsepower nor the s/w ability to handle a lot of the new stuff. The HX and SX series are running a DIFFERENT OS and have more memory and have faster processors. Sooner or later you run out of gas on the legacy -2 systems. And remember, their main task is to show you where you are relative to "shiny side up".

It has taken a lot of effort (pushing) to get some of the feature crammed into the SX series. And once it was explained to me why somethings would be difficult, I surely could see how it would be near impossible on the WS.

Just sayin ...

James E. Clark
Columbia, SC
RV6 Flying, RV6A Cowling
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Old 04-11-2015, 10:49 AM
gerrychuck gerrychuck is offline
Join Date: Jun 2011
Location: Moose Jaw, SK, Canada
Posts: 548

So, just to confirm; an HX with the latest updates does have the calculated AOA function? I have a used, but fully updated unit waiting to go into my panel, and I have found the manual and release notes very confusing on this point.
Gerry Julian
Moose Jaw Saskatchewan
RV6A "Second Wind" C-GERZ (born N242UL)
O-360 A1A, Sensenich FP prop

Those who think any system is foolproof greatly underestimate the ingenuity of fools
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Old 04-11-2015, 12:39 PM
BobTurner BobTurner is offline
Join Date: Dec 2011
Location: Livermore, CA
Posts: 6,575

Yes, an HX with recent software (actually several years now) should have the calculated AOA capability. Look for release notes, the manuals tend to lag behind. As you know, you can easily download the newest software (free) if you don't have it.
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