Icing encounter - your thoughts

Discussion in 'Flight Following' started by blueskyMD, Nov 19, 2017.

  1. Sundancer

    Sundancer Pattern Altitude

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    Just me, and I could be wrong . .but you oughta write your response, then let it sit for an hour, go back and read it. Before posting. And perhaps read the OP's posts with greater attention. The FAA reference seems to me to be particularly off-point, and nothing in any of the OP's post are a "good example of hazardous attitudes the FAA test for".
     
  2. Velocity173

    Velocity173 Final Approach

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    I think most of these "toys" would need a faluire of both GPS signal and Air data to fail the attitude indicator. The G5 doesn't even mention in the manual to troubleshoot airspeed for a failed attitude.

    I'm curious as to how these PFD / MFDs know that a pitot tube is blocked vs a normal 0 airspeed indication???
     
    Last edited: Nov 24, 2017
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  3. iamtheari

    iamtheari Cleared for Takeoff

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    POA rules prohibit considering the possibility of having misinterpreted other posts. If I was off-base, then I apologize to any whose constitution allows them to be offended by my post. But what I saw here is that the OP flew into likely icing, actually picked up icing, and when he got called out here for that part of his flight his response came across to me and, evidently, others as arrogantly hanging his hat on the chances of icing only having been 50% and anyhow he has flown in icing plenty of other times. Roll the dice until you get snake-eyes if you want, but being lucky in the past doesn’t have any bearing on whether you’ll be lucky in the present.
     
  4. Sundancer

    Sundancer Pattern Altitude

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    Oh, I wasn't offended; I didn't agree with your evaluation, which to my mind was far enough off the mark to warrant comment.
     
  5. Clark1961

    Clark1961 Touchdown! Greaser!

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    It’s okay to miss a point. With time perhaps it will be learned. Perhaps not,
     
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  6. Radar Contact

    Radar Contact Cleared for Takeoff

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    I hear you with regards to all eggs in one basket. I personally like the display and functionality of the G5 (would love the G500 TXi but too rich for me). I personally love the idea of as many independent redundant ("brass") systems I can have. I didn't get rid of anything to get my cheap glass. I still have my vacuum AI, ASI, VSI, HSI, ALT and even a real old school T&B. I learned needle/ball/airspeed and while I'd prefer to not do it in IMC for funsies, it's all still there if my G5 goes dark and my vacuum pumps go TU. Having a dual vacuum pump failure would be a very low risk, more likely the AI would break and if that happens I have the G5 to help me.
     
  7. iamtheari

    iamtheari Cleared for Takeoff

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    The surprising thing comes from the fact that the Stratus can give a reasonable attitude solution without any air data. What I would expect is for the Aspen to flag “attitude solution degraded, cross check with other instruments” and give a reasonable solution. rather than just shutting down the attitude display altogether. Pitot ice is way too high-probability to accept loss of attitude display as a consequence.
     
  8. Radar Contact

    Radar Contact Cleared for Takeoff

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    That's what Garmin says the G5 does.

    Agreed.
     
  9. hindsight2020

    hindsight2020 En-Route

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    Do we know for a fact Aspen doesn't have reversion to GPS speed input for its attitude gonculation? Haven't looked at a manual for the product, so genuinely curious.

    Also, aren't their installations still limited to retaining a second non-electric AI or electric AI with second electrical system? If so, that would make the consumer grade shenanigans less of an issue (my outright exception to their installed pricing notwithstanding). Again, honest question since I'm not familiar with their STC.
     
  10. Clark1961

    Clark1961 Touchdown! Greaser!

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    For a single Aspen installation a backup attitude indicator is required just like any other PFD.
     
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  11. iamtheari

    iamtheari Cleared for Takeoff

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    Is a backup required for a triple Aspen installation? It apparently should be.
     
  12. Clark1961

    Clark1961 Touchdown! Greaser!

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    The only relevant instal is the double Aspen installation with a PFD + MFD/PFD which will have two AH sensors. The third Aspen is always a “dummy” display. No backup AI is required if an additional battery is installed and perhaps other requirements met. I don’t know the full details just heard a few mutterings from an avionics guy about a difficult installation and an OCD owner. Basically the avionics guy said he wouldn’t even try to do the installation without a backup AI. This stuff is certified guys so even though you may not like the superficial details it isn’t designed and spec’d to automatically kill you if something fails.

    Edit to add: be smart about the installation of any PFD guys. I kept all the steam gauges except the VSI when I had the Aspen installed. I also had a wet vacuum pump installed. A lot of things have to go bad before instrument failure is a major problem in the ‘kota. It also drives CFIIs mad because they can’t realistically fail everything...
     
  13. Fearless Tower

    Fearless Tower Touchdown! Greaser!

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    You assume too much. Actually it’s from a Cessna checklist....
     
  14. Fearless Tower

    Fearless Tower Touchdown! Greaser!

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    You still haven’t answered the question: are you doing this stuff in an airplane that has some de-ice capability other than just pitot heat?
     
  15. Velocity173

    Velocity173 Final Approach

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    Windshield defogger. :D
     
  16. Clark1961

    Clark1961 Touchdown! Greaser!

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    Your reading and comprehension are lacking. I clearly said “along the lines of...”
     
  17. Fearless Tower

    Fearless Tower Touchdown! Greaser!

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    You must have gotten some bad turkey yesterday....
     
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  18. hindsight2020

    hindsight2020 En-Route

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    I don't think the OP ADM is terrible. The planning was legit. He had clear air in cruise and melting altitudes below the whole way. He clipped a couple cloud tops and got more icing than forecasted. No biggie. The only thing I would have done differently was request the descent as soon as I identified the trace airframe ice, instead of just accepting it and have the pitot heat failure/underperformance force my hand into the decision that by reg should have occurred immediately upon ice ID.

    The OP learned a great lesson when the Aspen gave him the finger, a great thing to learn about the system he trusts his life with, and a relatively benign lesson in how quickly something vanilla like a little trace icing can compound into complications that can ruin your day when combined with other aircraft system nuances like a weaksauce pitot heat for instance. Honestly as far as lessons for free goes, this one is a good one. The OP will be more vigilant of ice encounters in his airplane, address the pitot element issue/electrical, and be more springloaded in the future to treat inadvertent ice, even trace, with the expediency it requires in any non-FIKI spam can.
     
  19. Timbeck2

    Timbeck2 En-Route

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    He must eat bad turkey a lot.
     
  20. Rockymountain

    Rockymountain Pre-takeoff checklist

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    Sounds like you got beat up here pretty well. If you are still following, within this thread is plenty of sage advice. There is no icing that a non-FIKI aircraft is OK in. That is for a lot of reasons. The POH doesn't tell you what ice does to Vspeeds, the induction system, stall system, flap positions. Certification didn't explore whether the airframe is susceptible to tail stall, or the failure points of that aircraft in ice. You also did not receive airframe specific training on icing generated from the engineers and test pilots.

    Perhaps, most important to the above discussion. All the forecasts in the world cannot prepare you for what you might find in the clouds below freezing. Forecasts are just forecasts, and often wrong in both directions. Also keep in mind that trace or light icing for one airframe may be moderate or severe for another. I would just say, don't mess with ice in a non-FIKI aircraft. You will never know how close to the edge you are, since in essence you are a test pilot. Fly safe.
     
  21. mscard88

    mscard88 Touchdown! Greaser!

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    I don't think it's bad turkey, I think it's buzzard he eats. :rofl::rofl::rofl:
     
  22. midwestpa24

    midwestpa24 Line Up and Wait

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    I am still baffled. Why design an attitude indicator that will totally fail because of a pitot-static problem? That seems so backwards, the two should be independent. A failure of one system should not cause failures of others. I could see the Aspen x-ing out the airspeed indication, but why make the attitude indication use that data? If I have a pitot-static failure, I want an attitude indicator. If I have an attitude indicator failure, I want my pitot-static stuff. Makes no sense.
     
  23. Velocity173

    Velocity173 Final Approach

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    These EFIS displays usually require either an air data (airspeed) or a GPS ground speed. The unit uses an algorithm from either of the two to compute a correct attitude. My Blue Mountain requires a GPS signal for the attitude. As a matter of fact, it just failed the other day when I lost GPS signal. The Garmin 500H I fly for work, requires one or the other. My G5, well, I haven't quite figure out yet but I imagine it requires one or the other.

    My question still remains, how does it know to put a red X for 0 airspeed as an incorrect indication???
     
    Last edited: Nov 25, 2017
  24. Clark1961

    Clark1961 Touchdown! Greaser!

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    The Aspen has a backup GPS. I suspect it uses GPS speed to determine that airspeed is bad. Why it doesn’t fail over to GPS speed is something I have no clue about.
     
  25. Velocity173

    Velocity173 Final Approach

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    And since the OP didn't mention losing a GPS signal, no reason why the attitude should have been red X'd. If that's how an Aspen works, I don't want one.
     
  26. Clark1961

    Clark1961 Touchdown! Greaser!

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    There’s a backup AI so I’m not too concerned. I did go with a wet pump since the backup AI also provides autopilot input.
     
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  27. Radar Contact

    Radar Contact Cleared for Takeoff

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    I agree. Did you watch that video of the Atlantic crossing posted above? You can see the ASI go to zero and the Aspens both failed completely. I would say there is almost a zero chance that at the same second the pitot got blocked the GPS's also lost signal. That is an eye opening failure. For those of us that will always choose to keep a vacuum AI it wouldn't be too catastrophic other than attention diverting while IMC but there are people installing these dual units and removing their traditional AI's...that is a scary scenario.
     
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  28. Velocity173

    Velocity173 Final Approach

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    Well if you have a backup that's non GPS/air data then it's no big deal. I've got a vacuum backup to my crappy Blue Mountain so I'm not too worried. Still, I would think for a certified display like the Aspen, it wouldn't require both inputs in order to display attitude.
     
  29. hindsight2020

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    Occam's Razor. The box was certified with the provision the mechanical AI to remain in place as part of the *STC (*single box installation variant), therefore Aspen can afford to be ham-handed about their fail modes. That's it man, no conspiracy. I hear that though, for what they're charging for that box, hoo boy. But I've already said my peace about that in a previous post so I digress.

    The good news is that it's just software, they could just as easily flash a software revision where they merely flag it as opposed to Xing it out. Of course, they could also write the code to take in the GPS speed as reversion mode, and voila, backup to the pitot.

    What it does show is that Aspen is comfortable coasting downhill and cashing checks. They got their little cow and they're milking it. Their monkey their circus, and as long as folk line up to pay 15K installed for their IFR software boxes, then there's not really a problem now is there?

    Gotta vote with your wallet.
     
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  30. midwestpa24

    midwestpa24 Line Up and Wait

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    I will admit to having ZERO glass panel experience. I knew EFIS did not use typical gyros as such for information. I guess I though there was some whiz-bang solid state accelerometer or something that provided the attitude indications. I would have never guessed it was using pitot/static information, or that a single point failure of the pitot/static system would affect attitude indications. Learn something new everyday.
     
  31. hindsight2020

    hindsight2020 En-Route

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    You're conflating terms here. EFIS has nothing to do with attitude. I know it was a TL;DR post, but I encourage you to re-read post #38. I explained the differences between direct attitude measurement instrumentation (mechanical gyro, RLG) and accelerometer-based "back-solving" attitude instrumentation (most consumer grade stuff). The methodologies of arriving at attitude information are fundamentally different between the two, and not at all an inconsequential difference.
     
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  32. iamtheari

    iamtheari Cleared for Takeoff

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  33. hindsight2020

    hindsight2020 En-Route

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    yes, and hopefully the fanbois on here will finally realize the pitfalls of bringing a knife to a gunfight just because you spent gun money for it.
     
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  34. Velocity173

    Velocity173 Final Approach

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    Not sure why you're hating on these EFIS displays but the odds of my G5 or our G500H losing both air data and GPS simultaneously is slim. If it does, that's what a mechanical backup is for.

    We might be spending "gun money" but what's the alternative? Yes, a RLG or the FOGS I flew in the Army is much more advanced but I'm not going buy something that costs more than my plane either.
     
    Last edited: Nov 25, 2017
  35. hindsight2020

    hindsight2020 En-Route

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    dont misunderstand, im not hating on the merits of ga glass, im just throwing spears back at the cohort that came at me with the socioeconomic ad hominem just because i dared highlight the limitations that system has over traditional electric/vacuum six pack.

    this also happens to be a spillover argument from another forum, so forgive me for the lack of context. this has nothing to do with aspen or g5, its more about a sweater wearing richard or two. so we're cool brother. :D
     
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  36. danhagan

    danhagan Cleared for Takeoff

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    Just spray you’re leading edges and prop with “Easy Off” oven cleaner .... ice just flies off (this is of course a joke to apply a little levity to this thread)