Cirrus down in Texas

Discussion in 'Aviation Mishaps' started by PaulS, Sep 2, 2022.

  1. Tantalum

    Tantalum Final Approach

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    Damn! Thanks for sharing and glad everything is okay!
     
  2. MFE

    MFE Pre-Flight

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    Pictures from the scene show the chute deployed but not really opened.
     
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  3. Ed Haywood

    Ed Haywood Pattern Altitude

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    Well done!!!
     
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  4. mandm

    mandm Line Up and Wait

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    Did you gear up or down? What did you do after you landed? Glad everyone is ok.
     
  5. RyanShort1

    RyanShort1 En-Route

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    Like I said, this thread is about the Cirrus, I was just commenting on the mindset. I’ll probably post a better writeup later. The good news is that two of the people on board the Cirrus appear to have survived, so hopefully we'll get a better idea of what went wrong eventually.
     
    Last edited: Sep 3, 2022
  6. Kritchlow

    Kritchlow Final Approach

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    Classy response to not make this tragedy about you.
     
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  7. Flying Keys

    Flying Keys Pre-takeoff checklist

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    Here are a few things that might help you visualize the situation.
    3D Views:
    1) Looking NE
    N420SS 3D View.JPG
    The blue ball is where the AP Altitude hold was turned off. LNAV mode continued being active until a slight level off, leading to the red ball, where the AP was completely turned off:

    2 )Looking fairly down the runway to the north-northwest
    N420SS 3D View Alt.JPG

    3) Profile view, looking west:
    N420SS Profile.JPG

    4) Closer profile of the short final
    N420SS Profile Close.JPG

    5) Planview of the flight path with 2100 Radar Mosiac (2055 and 2105 Mosaics did not provide much additional insight - no developments in the immediate vicinity or indications of outflow, etc).
    N420SS 2D with radar overlay.JPG

    6) Closer-in planview without radar
    N420SS 2D close.JPG

    I'm aware this was a visual approach, but for reference I added FLICKA, the FAF for the LOC 17R approach, pegged to the minimum altitude of 1800 MSL

    As noted above, there was a slight level-off prior to the AP turning off, at which point, they entered a pretty steep descent and a slight right turn just before the ADS-B trail ended.

    That's about all I have - the only armchair analysis I can add is that I don't think weather was a factor as the returns were pretty far away and there were too many other a/c in the pattern to not notice windshear.
     
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  8. PaulS

    PaulS Touchdown! Greaser!

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    That's cool graphic. @scottd on another forum had a Nexrad Level II sequence for KGHX showing an outflow boundary and collapsing cell over the approach corridor for this airport. He said that the data we see removes the outflow stuff because it doesn't have precip in it. The more I learn about this weather stuff, the less I realize I know.

    It would be cool to see your location data on that image.
     
  9. Himayeti

    Himayeti Pre-Flight

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    1. How high were they when engine quit? 1800ft?
    2. Distance from closest runway at that point?

    Assuming a glide ratio of 8.8:1 (from the SR22 manual) at 1800 feet and if flown properly, they would make it from 2.99 miles out.

    Any excess speed over best glide, you should also point the nose up right away until you reach it, so as to gain some extra distance. You can even use the wind in your favor and land with a tailwind if it gets you to the runway.
     
  10. PaulS

    PaulS Touchdown! Greaser!

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    That glide is clean, with flaps they fly like a rock. Apparently this guy was (is?) an experienced pilot with a factory pilot on board. I'm really starting to think they drew the unlucky card.
     
  11. TrueCourse

    TrueCourse Line Up and Wait

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    Q1 and Q2 was discussed earlier in the thread.
     
  12. Flying Keys

    Flying Keys Pre-takeoff checklist

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    I’d like to see that. I have the raw level II data, but no way to open it. However, I looked at the base echoes and velocities from a different commercial site and there is no evidence of outflow at that location at that time. The storms to the north didn't collapse for over an hour after the accident; a relatively weak outflow reached KDWH at about 2313Z. At that point the wind did shift to northerly, as you would expect.

    KDWH 012153Z 23007KT 10SM CLR 32/24 A2990 RMK AO2 LTG DSNT NW-NE SLP121 T03220239
    KDWH 012253Z 18003KT 10SM CLR 31/23 A2990 RMK AO2 LTG DSNT NW-NE SLP123 T03110228
    KDWH 012353Z 02004KT 10SM SCT040 SCT050 28/22 A2992 RMK AO2 LTG DSNT NW SLP130 T02830222 10356 20283 53009

    There was additional outflow from a collapsing storm just southeast of Downtown Houston, but that was mitigated by the outflow from the north and never reached the field.

    Not sure what you're looking for as far as location data. I downloaded the kml of the flight path from Flightradar 24 and imported it into Google Earth. The radar data were overlaid in GE using geographic references on the respective basemaps. The point-by-point analyses were mine. Quick and dirty, but I stand behind it.
     
  13. Flying Keys

    Flying Keys Pre-takeoff checklist

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    Something changed in the 10 seconds prior to AP disconnect. The descent rate and groundspeed both started falling. Then after the AP went off, the descent rate increased dramatically without a big increase in groundspeed.

    EDIT: Actually, it looks like it was simply leveling off at the target autopilot altitude of 960ft. Makes you wonder if it just got slow as the altitude was being captured, then went into a steep, but slow descent when they kicked it off.
     
    Last edited: Sep 5, 2022
  14. Flying Keys

    Flying Keys Pre-takeoff checklist

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    They were well above the nominal 3° glidepath provided by the PAPI until just after the AP disconnect (when they quickly went below it). The level-off between 4 and 5 nm from the PAPI units brought them almost 250' above GP at both the 4nm and 3nm distances, respectively. At 2nm, they were still almost 200' above GP, that's when a second level-off occurred (presumably an altitude capture of 960'), just before the AP was disconnected.

    This is not to presume any airmanship or mechanical errors, just bringing to light some facts for our situational awareness.

    EDIT: To put this in perspective, at 4nm from the PAPI, when they began the descent, they would have had to fly a 3.75° glidepath to make the touchdown zone. At 2NM, after the second level-off and AP disconnect, they were still needing to fly the same glidepath.
     
    Last edited: Sep 5, 2022
  15. Kenny Phillips

    Kenny Phillips En-Route

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    Hopefully no stall regime; I believe that all Cirrus aircraft have "envelope protection" as that's part of Garmin's system.
    This is an odd one, though we later find that most "odd" crashes really do have mundane causes.
     
  16. benyflyguy

    benyflyguy En-Route PoA Supporter

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    With the steep descent with ap coming off makes me wonder about a runaway trim at a really bad time ??
     
  17. donjohnston

    donjohnston Pattern Altitude

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    How was it determined when the AP was disconnected?
     
  18. LesGawlik

    LesGawlik Line Up and Wait

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    ADSB will show AP mode and disconnect.
     
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  19. Flying Keys

    Flying Keys Pre-takeoff checklist

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    Completely disagree in this case. There was no outflow at or near the field at the time of the final approach. Everything was fairly good (even higher than normal glidepath) until they clicked off the autopilot. The outflow you show would have not produced that result unless the final approach occurred an hour after it did.
     
  20. Flying Keys

    Flying Keys Pre-takeoff checklist

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    Not only that, but the resultant flightpath agrees with the A/P data.
     
  21. donjohnston

    donjohnston Pattern Altitude

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    What?

    Is this just a Cirrus thing?
     
  22. LesGawlik

    LesGawlik Line Up and Wait

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    Nope. I didn't believe it either, but I've seen ASDB traces that showed AP function.
     
  23. PaulS

    PaulS Touchdown! Greaser!

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    It would be cool to add the flight path to Scott's animation. If you had an event strong enough to cause the aircraft to fall out of the sky the AP would disconnect on it's own.
     
  24. Flying Keys

    Flying Keys Pre-takeoff checklist

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    You’re flying away from the proposed shear. In this case, you’d get increasing performance.
     
  25. Flying Keys

    Flying Keys Pre-takeoff checklist

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    Looking at the ADS-B track, there is no reason to suspect shear.

    Looking at the METAR, there is no reason to suspect shear at that time.

    Looking at the radar, there is reason to suspect shear an hour after the accident, when the outflow did indeed pass and shift the wind to the north, as indicated by the last METAR I posted above.

    How many other planes were in the pattern? Did any of them indicate shear enough to knock an airplane high on approach out of the sky? Was it coincidence that it was slowing the descent to capture the preselected AP altitude and as soon as the AP kicked off, it began a steady descent to the ground?
     
  26. Flying Keys

    Flying Keys Pre-takeoff checklist

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    Also, you’d only get about three radar frames with the aircraft in it. The outflow from the collapsing northern storm did not reach the field for another hour.
     
  27. donjohnston

    donjohnston Pattern Altitude

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    I guarantee that you wouldn't see it on the plane I built.
     
  28. Chicago Bearhawk

    Chicago Bearhawk Pre-Flight

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    I once saw a video where an old military pilot said an engine out was actually better than a partial power or intermittent power, there is no way I can find it now but it might have been on AOPA...

    The one think that was drilled into me during training was best glide give you max distance. you will not go a farther distance by stretching the guild.
     
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  29. PaulS

    PaulS Touchdown! Greaser!

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    Looks like Scott pulled the animation.
    I think with a partial engine failure you don't give up altitude. If you can't maintain altitude then you had better plan finding a place to put it down gently.
     
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  30. Fearless Tower

    Fearless Tower Touchdown! Greaser!

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    Depends on the autopilot. Some show the mode selected on ADS B, but they are the exception rather than the norm, at least right now.
     
  31. RyanShort1

    RyanShort1 En-Route

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    Agreed. If you think you have a GOOD landing option underneath you, you're probably more likely to save the plane, and possibly the engine, if you can do it while you have choice.