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  #71  
Old 04-07-2021, 05:11 PM
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HAL Pilot HAL Pilot is offline
 
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What I was trying to get at was for folks that don't have Anti Ice but do have Pitot heat they could use the 10 Celsius rule of thumb like the airlines do for anti ice if they don't want to keep it on all the time, and if the glass avionics offer a warning option for temperature.
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  #72  
Old 04-07-2021, 05:49 PM
rocketman1988 rocketman1988 is offline
 
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Location: Sunman, IN
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Default Understand

I understand; my point was that the airlines use the pitot heat all the time. In this case, using the pitot heat would have prevented the OPs issue, completely.

I equipped my -10 with the regulated pitot...it gets turned on after start and turned off at shutdown. Barring a mechanical failure, the Issue the OP had should never happen...
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  #73  
Old 04-07-2021, 07:54 PM
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Update on a another "lesson learned" since this incident occurred.....

The AP did NOT disengage when airspeed went to zero due to ice! I disengaged it manually.

Here's what happened (and I think it's good for all of us to know) the Garmin AP has a safety feature programed so if it sees airspeed dropping to stall speed, the servos will ease the nose over to avoid an anticipated stall. This feature goes away when air speed hits 30 KIAS. When my airspeed was dropping, AP was pitching nose down. When KIAS dropped below 30, I felt a sudden and strong pitch up (at same time stall warning goes off). My perception was that this was AP disengaging due to no airspeed. It was not. So, when I grabbed control stick, I was not concerned about hitting disconnect switch, which I did.

Bottom line, Garmin AP will work without any indicated airspeed! (Think ground checks.) I could have hit the Blue level button in this situation, but I didn't think it was working without airspeed. It was! Hopefully, this is another lesson for others that can save a life down the road.

Garmin is looking at some changes that may help others in my situation down the road. Thank you Garmin for using this to help us all. GREAT customer service!
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  #74  
Old 04-07-2021, 08:28 PM
David Z David Z is offline
 
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To clarify the previous comments about ice protection, pitot and static heat is on whenever airborne. It's the other ice protection systems (props, wings, windshield, engine intakes, etc.) that are turned on at +5*c or +10*c prior to, or after entry into visible moisture. All depends on the system, conditions, aircraft and company.
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  #75  
Old 04-07-2021, 10:45 PM
Flyfish Flyfish is offline
 
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Randy,
Thank you for posting this. You were really lucky as you already know. Your attitude toward learning and teaching is commendable and should be praised greatly.

As a Commercial pilot that has flown most of my entire career single pilot, I can say one thing for certain. Your skills saved your life. You struggled, but you ultimately won.

That said, I hate when the conversation revolves around technology and auto pilot safety. Your video shows exactly what happens when technology fails and a pilot is too reliant upon it for success. Technology literally can "fail" because we "disengaged" it ourselves. In fact, as you know, you were on the verge of failing more technology by randomly pulling circuit breakers.

Again, you did an amazing job. Be proud that you saved your life.

I hope people can see that more technology in their aircraft is not neccisarily the answer to increased safety. But that solid proficient skills will always trump technology.

Thanks for sharing
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  #76  
Old 04-08-2021, 10:06 AM
jjb jjb is offline
 
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Default Another Thanks To OP and Follow Up Question

Quote:
Originally Posted by rvanstory View Post
Update on a another "lesson learned" since this incident occurred.....

The AP did NOT disengage when airspeed went to zero due to ice! I disengaged it manually.

Here's what happened (and I think it's good for all of us to know) the Garmin AP has a safety feature programed so if it sees airspeed dropping to stall speed, the servos will ease the nose over to avoid an anticipated stall. This feature goes away when air speed hits 30 KIAS. When my airspeed was dropping, AP was pitching nose down. When KIAS dropped below 30, I felt a sudden and strong pitch up (at same time stall warning goes off). My perception was that this was AP disengaging due to no airspeed. It was not. So, when I grabbed control stick, I was not concerned about hitting disconnect switch, which I did.

Bottom line, Garmin AP will work without any indicated airspeed! (Think ground checks.) I could have hit the Blue level button in this situation, but I didn't think it was working without airspeed. It was! Hopefully, this is another lesson for others that can save a life down the road.

Garmin is looking at some changes that may help others in my situation down the road. Thank you Garmin for using this to help us all. GREAT customer service!
Many thanks for following up on the autopilot disconnect aspect. I am currently installing and wiring an almost identical dual G3X system, albeit in my RV-7 project, so this has been of interest.

Modern autoflight systems are complex enough that those like me who come from an airline or other professional flying background would probably agree that they have more than once heard or made the comment “why’d it do that?” on flight decks at work when the autopilot was engaged.

And the modern glass that we put in our little airplanes is every bit as full featured as those in modern heavy metal.

There is one question for the OP that is not clear to me at least. Did you hit the CWS (autopilot disconnect for those not familiar with Garmin-speak) button on purpose, or was it inadvertently pressed when placing your palm on the stick during that moment of stress, turbulence and high workload?

For those still in the decision making phase on stick button ergonomics, does placement of the autopilot CWS/disconnect button on the front of the stick right underneath where the palm normally rests create an increased susceptibility of inadvertent actuation?
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  #77  
Old 04-08-2021, 11:08 AM
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Longez Longez is offline
 
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Randy,

I want to join others in thanking you for bravely sharing your experience and your video. Most of us will never experience an iced up pitot probe, but watching your airspeed go from normal to zero in a few seconds was quite eye opening! Good job keeping the plane upright while you sorted things out and got the pitot heat going!

You invested wisely in your avionics. It is probably safe to say that most, if not all, modern ADAHRS units use airspeed in their attitude calculation algorithms, and the fact that your two independent, dissimilar, G5 and GSU 25 ADAHRS units were able to immediately recognize the loss of valid airspeed data (without any airspeed sensor failure in either unit) and adapt their calculations to use the remaining air and GPS data to keep your attitude indications rock solid and continue to support the pilot and autopilot is impressive.

Similarly, when you turned pitot heat on, your pitot thawed out, and your airspeed jumped from zero to normal speed in a few seconds, both of your ADAHRS units were again rock solid and were not negatively affected.

I have this equipment in my plane, and am glad to see that if I were to suffer a similar iced up pitot situation, the G5 and GSU 25 would continue to reliably provide altitude, pitch, roll, and yaw.

Quote:
Originally Posted by rvanstory View Post
Bottom line, Garmin AP will work without any indicated airspeed! (Think ground checks.) I could have hit the Blue level button in this situation, but I didn't think it was working without airspeed. It was! Hopefully, this is another lesson for others that can save a life down the road.
The blue level button has been mentioned a couple of times in this thread, and I want to point out that using this button is entirely optional and not at all necessary, under any condition, to re-engage your autopilot.

Your autopilot was manually disengaged, but the flight director (autopilot modes) was still setup, and all that was necessary to restore the autopilot was to reach up and press the AP button in the center of the control panel.



Even though you temporarily lost the use of IAS (airspeed hold) mode on your G3X Touch autopilot until your pitot probe thawed out, all of the other modes were fully operational and available to you.

One other comment is in regards to your AOA audio volume. The AOA tones volume level is independently adjustable from the Sound configuration page in your G3X Touch system. You might want to consider turning it down a bit. Personally, I have mine set rather low. It just loud enough to be a gentle reminder to me, but not so loud that it disturbs passengers or would be much of a distraction if it were on full time like yours was. Of course, turning off the audio panel while still retaining COM1 capability is another option to remove the distraction.

Thanks,
Steve
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  #78  
Old 04-08-2021, 07:48 PM
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rvanstory rvanstory is offline
 
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Quote:
Originally Posted by jjb View Post
There is one question for the OP that is not clear to me at least. Did you hit the CWS (autopilot disconnect for those not familiar with Garmin-speak) button on purpose, or was it inadvertently pressed when placing your palm on the stick during that moment of stress, turbulence and high workload?
The short answer is, it was inadvertent.

I was convinced the AP had already disconnected itself, so in that moment, I wasn't concerned about hitting the AP disconnect button on my stick, nor was I trying to on purpose. Usually, I'm very aware of the disconnect button and always have a "light touch" on the stick to I won't disengage it with a strong grip. In this moment, I didn't care about a strong grip or the inadvertent disconnect of something I believed to be already "disconnected".

The Garmin data logs are VERY detailed. They showed it was a "manual disconnect", meaning, I hit the button. I was not trying to, nor was I trying not to, it just happened in the stress of everything else.

Hope this gives clarity to your question.
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  #79  
Old 04-08-2021, 10:38 PM
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HAL Pilot HAL Pilot is offline
 
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Another future configuration option that would be nice for these Glass systems is a audio alert when the autopilot kicks off on its own and a similar but different tone when its kicked off manually. For example a "Autopilot autopilot" for inadvertent disconnect. TACK TACK sound for manual disconnect.
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  #80  
Old 04-09-2021, 07:41 AM
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rvanstory rvanstory is offline
 
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Quote:
Originally Posted by HAL Pilot View Post
Another future configuration option that would be nice for these Glass systems is a audio alert when the autopilot kicks off on its own and a similar but different tone when its kicked off manually. For example a "Autopilot autopilot" for inadvertent disconnect. TACK TACK sound for manual disconnect.
It already does have a different alert. See clarifying post #37 by G3Xpert. https://vansairforce.net/community/s...6&postcount=37
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