Video and Discussion - Burley, ID accident. Was "Gryder"

Let'sgoflying! said:
1. Fly down to MDA as depicted.
2. If you don't have good visuals at the MAP, don't descend; fly away.

/handwringing about unimportant details.
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Well, at least part this thread is/was focused on showing that Gryder's analyis is not valid, so that's not really handwringing, per se. But yes -- once below MDA it's on the pilot to remain visual and avoid obstacles. I don't think anyone disagrees with that.
 
Turbo-Arrow-Driver said:
Well, at least part this thread is/was focused on showing that Gryder's analyis is not valid, so that's not really handwringing, per se. But yes -- once below MDA it's on the pilot to remain visual and avoid obstacles. I don't think anyone disagrees with that.
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I guess I just don't care either way about his analysis since if you fly the approach as published (or even a bit more conservative) there is no issue.
 
TrueCourse said:
There are FMS systems that automatically create the correct path to honor step down fixes, I just haven’t figured out all the Garmin logic yet. I did notice the GTN trainer at this airport will show you the path (VNAV page, path in degrees) being used as you get close the FAF, then crossing the FAF the path isn’t displayed (VNAV page). Has something to do with the step down or non precision nature of the approach.
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I just tried another experiment with the Garmin simulator for the GNX375. Turns out Garmin has extended the 3.75 degree slope all the way back to IREME -- at about 8600 or 8700 MSL. Arriving at IREME at about 8600, Garmin will start displaying a GS indication and the a/c will be on the slope at IREME, and the GNX375 will guide the a/c down a 3.75 degree slope all the way to MDA from that point.
 
The GTN650xi trainer I used was showing the sub 2 degree slope from IREME to HIKLO then it went to 3 degrees after HIKLO. I could have changed the VNAV to 3.75 early but it would drop that passing the FAF.
 
TrueCourse said:
The GTN650xi trainer I used was showing the sub 2 degree slope from IREME to HIKLO then it went to 3 degrees after HIKLO. I could have changed the VNAV to 3.75 early but it would drop that passing the FAF.
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Interesting. You can get the other behavior if you go to the flight plan and click on the altitude for IREME and HIKLO, then click "Remove Constraint". After this, the arrow on the vertical tracking scale changes to a diamond. I don't use one of those displays, so I have no idea what the arrow vs diamond symbology means, but it will track a 3.75 degree slope from IREME to RW20 with this change.

650-3a.jpg 650-4a.jpg
 
Turbo-Arrow-Driver said:
Interesting. You can get the other behavior if you go to the flight plan and click on the altitude for IREME and HIKLO, then click "Remove Constraint". After this, the arrow on the vertical tracking scale changes to a diamond. I don't use one of those displays, so I have no idea what the arrow vs diamond symbology means, but it will track a 3.75 degree slope from IREME to RW20 with this change.
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@Turbo-Arrow-Driver ... the magenta chevron (<) on the VDI is for VNAV operations whereas the magenta diamond (◆) is for the Glidepath.

-- VNAV is used for (instrument arrivals and) instrument approach segments outside the segment leading to the FAF, in this case MUTOE (or JACUP) to IREME.

-- GP of course is used for the segment leading to the FAF and onward to the runway, in this case IREME to HIKLO, HIKLO to JAMID, and JAMID to RW20.

More discussion on G1000 vertical navigation here.
 
Turbo-Arrow-Driver said:
I just tried another experiment with the Garmin simulator for the GNX375. Turns out Garmin has extended the 3.75 degree slope all the way back to IREME -- at about 8600 or 8700 MSL. Arriving at IREME at about 8600, Garmin will start displaying a GS indication and the a/c will be on the slope at IREME, and the GNX375 will guide the a/c down a 3.75 degree slope all the way to MDA from that point.
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Do you get that just because you have activated the Approach? Or do you have to do something else like go to a VNAV page or something?
 
Salty said:
I guess I just don't care either way about his analysis since if you fly the approach as published (or even a bit more conservative) there is no issue.
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It started with his analysis. But I think we’ve moved beyond that and this particular accident a couple pages ago. It’s turned into a pretty good Garminology and VDA discussion I would say. Do you use a Garmin Navigator? Have you found this useful? Maybe the Mods could pick this up at a certain post above, move it to a new thread with a new name in Cleared for the Approach. We’re probably not getting a lot of good input from the usual cast of characters who are very knowledgeable about this stuff because they would rather stick red hot ice picks in their eyes rather than click on a thread named Gryder.
 
My takeaway from all of this is that some people are trying to fly all GPS approaches like they're ILS glideslopes, and they're not. And I'm not speaking about the accident airplane or the youtube guy.
 
luvflyin said:
Do you get that just because you have activated the Approach?...
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On Garmin units, the only thing "activating" the approach does is take you directly from your present position to whichever IAF you chose when you loaded the approach. The one exception is if you chose VTF, in which case I think it activates the leg that leads to the FAF or FAP.
 
Palmpilot said:
On Garmin units, the only thing "activating" the approach does is take you directly from your present position to whichever IAF you chose when you loaded the approach. The one exception is if you chose VTF, in which case I think it activates the leg that leads to the FAF or FAP.
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If you activate an ILS Approach, get on the Localizer, don’t you get the Glideslope? You don’t have to push another button for that. This whole thing we’re talking about here is vertical navigation.
 
I don’t understand how it’s ever possible for the unofficial GP ever to go lower than where you’d be diving and driving. Crossing Fix A at 2000’, followed two minutes later by B at 1000’, Garmin would put you on a steady 500fpm descent at some angle. Halfway between A and B, you’d be at 1500’. Diving and driving, you’d cross A at 2000’, chop the power, level off at 1000’, add some power back, and cross B at 1000’. At the halfway point, you’d surely be lower than the 1500’ the GP would’ve given.

When is the GP ever lower than where you’d be, diving and driving?
 
OneCharlieTango said:
I don’t understand how it’s ever possible for the unofficial GP ever to go lower than where you’d be diving and driving. Crossing Fix A at 2000’, followed two minutes later by B at 1000’, Garmin would put you on a steady 500fpm descent at some angle. Halfway between A and B, you’d be at 1500’. Diving and driving, you’d cross A at 2000’, chop the power, level off at 1000’, add some power back, and cross B at 1000’. At the halfway point, you’d surely be lower than the 1500’ the GP would’ve given.

When is the GP ever lower than where you’d be, diving and driving?
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It doesn’t. This isn’t about a comparison between dive n drive and the ‘unofficial GP.’ It doesn’t draw a line that is lower where a dive n drive would be.
 
luvflyin said:
If you activate an ILS Approach, get on the Localizer, don’t you get the Glideslope? You don’t have to push another button for that. This whole thing we’re talking about here is vertical navigation.
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Yes, but on a G1000 you don't have to activate the approach in order for that to happen. Merely loading the approach is sufficient to cause those things to happen when you reach the appropriate location.

In my experience, when you either load or activate an ILS approach on a G1000, the CDI remains coupled to the GPS, but it automatically switches to the localizer by the time you intercept the localizer course. I don't recall when it starts displaying the glideslope, but that too is automatic.

The reason I brought this up is that it's important to know that activating the approach takes you to whatever IAF you selected (if you selected one). The trap you can fall into is that if you activate (or reactivate) the approach after passing the IAF, the unit will assume you want to go back to the IAF! I found this out the hard way on the Livermore (LVK) ILS one day.

The other current Garmin models may behave similarly, but I don't have enough experience with them to be sure.
 
Palmpilot said:
Yes, but on a G1000 you don't have to activate the approach in order for that to happen. Merely loading the approach is sufficient to cause those things to happen when you reach the appropriate location.

In my experience, when you either load or activate an ILS approach on a G1000, the CDI remains coupled to the GPS, but it automatically switches to the localizer by the time you intercept the localizer course. I don't recall when it starts displaying the glideslope, but that too is automatic.

The reason I brought this up is that it's important to know that activating the approach takes you to whatever IAF you selected (if you selected one). The trap you can fall into is that if you activate (or reactivate) the approach after passing the IAF, the unit will assume you want to go back to the IAF! I found this out the hard way on the Livermore (LVK) ILS one day.

The other current Garmin models may behave similarly, but I don't have enough experience with them to be sure.
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Yeah. I shouldn’t a said “…activate the approach…” My bad. The point was if the approach is active, it will give you needles/diamonds or whatever. I was just talking about the vertical aspect of it. That’s what we been doin here.
 
It appears these multi-angle approaches, although described as "rare cases" in the FAA AC120-108, are not super rare. I just had a look at the O60 RNAV 32 approach (Cloverdale, Calif), and it has a much larger slope change. The descent angle from IF to FAF is 0.84 degrees (133 fpm descent rate @ 90kt), and from FAF to runway threshold is 3.50 degrees (557 fpm descent rate @ 90kt).

Extending the 3.50 degree slope all the way from runway threshold to IF puts you at 5000 MSL.

The GNX375 simulator will show you "on glideslope" at the IF -- HOTIN -- if you arrive there at 5000 ft, and will give you an constant descent angle all the way from there to MAP. I didn't try it, but the Garmin GTN units will probably do the same if you enable the "remove constraint" option for HOTIN.

This seems like something useful to know about how some Garmin GPS navigators work.
 
Turbo-Arrow-Driver said:
It appears these multi-angle approaches, although described as "rare cases" in the FAA AC120-108, are not super rare. I just had a look at the O60 RNAV 32 approach (Cloverdale, Calif), and it has a much larger slope change. The descent angle from IF to FAF is 0.84 degrees (133 fpm descent rate @ 90kt), and from FAF to runway threshold is 3.50 degrees (557 fpm descent rate @ 90kt).

Extending the 3.50 degree slope all the way from runway threshold to IF puts you at 5000 MSL.

The GNX375 simulator will show you "on glideslope" at the IF -- HOTIN -- if you arrive there at 5000 ft, and will give you an constant descent angle all the way from there to MAP. I didn't try it, but the Garmin GTN units will probably do the same if you enable the "remove constraint" option for HOTIN.

This seems like something useful to know about how some Garmin GPS navigators work.
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I'm not seeing that as a multi angle Approach as concerns VDA's. There is no step-down fix. CIMAX is the FAF and that's where the VDA start's. I've never seen anything that says a VDA will start outside of the FAF. I've never done it, correct me if I'm wrong, but you can do VNAV(not as in a LNAV/VNAV approach) anywhere. You can tell it you want to cross fix, not on an Approach but out there on the airways, and it will calculate it for you, maybe even throw up some indications on the VDI. When you were doing doing your experiments, did you do anything other than load the Approach and let it activate on it's own or activate it yourself?
 
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You are correct -- I was not careful with my wording. My comments apply to approaches with advisory vertical guidance, prior to FAF. Here's what I should have said:

For approaches with step-down fixes that are +V (e.g. LNAV+V), the GNX and GTN units will project the VDA back all the way to the IF, and provide vertical guidance from that point, keeping the A/C at or above altitude restrictions on the approach, down to MDA (obstacle clearance is not guaranteed below MDA).

For the O60 aproach, you get constant angle vertical guidance starting at the IF (HOTIN). Using this, there's no need to change descent rate at the FAF.

Arriving at the IF at the specified minimum altitude (3100' at HOTIN for this approach), vertical guidance will show you low. Instead of immediately beginning a descent to the next altitude (2500' at CIMAX), I believe you have the option to maintain that altitude (e.g. 3100') until you intercept the vertical guidance, and then follow it down to MDA. In this case you would start the descent not at HOTIN, but 5 miles later. You still need to monitor the fixes and be sure to meet the altitude restrictions, but the vertical guidance should make that work. This eliminates the dive and drive between IF and FAF.

Arriving at a slightly higher altitude, you could potentially maintain that altitude until intercepting vertical guidance. For example, ATC might bring you in at a higher altitude (say 3500' in this example), with the approach clearance "maintain 3500 to HOTIN, cleared for the RNAV 32 approach". In this case, you might be able to stay at 3500' past HOTIN until intercepting the vertical guidance.
 
Turbo-Arrow-Driver said:
You are correct -- I was not careful with my wording. My comments apply to approaches with advisory vertical guidance, prior to FAF. Here's what I should have said:

For approaches with step-down fixes that are +V (e.g. LNAV+V), the GNX and GTN units will project the VDA back all the way to the IF, and provide vertical guidance from that point, keeping the A/C at or above altitude restrictions on the approach, down to MDA (obstacle clearance is not guaranteed below MDA).

For the O60 aproach, you get constant angle vertical guidance starting at the IF (HOTIN). Using this, there's no need to change descent rate at the FAF.

Arriving at the IF at the specified minimum altitude (3100' at HOTIN for this approach), vertical guidance will show you low. Instead of immediately beginning a descent to the next altitude (2500' at CIMAX), I believe you have the option to maintain that altitude (e.g. 3100') until you intercept the vertical guidance, and then follow it down to MDA. In this case you would start the descent not at HOTIN, but 5 miles later. You still need to monitor the fixes and be sure to meet the altitude restrictions, but the vertical guidance should make that work. This eliminates the dive and drive between IF and FAF.

Arriving at a slightly higher altitude, you could potentially maintain that altitude until intercepting vertical guidance. For example, ATC might bring you in at a higher altitude (say 3500' in this example), with the approach clearance "maintain 3500 to HOTIN, cleared for the RNAV 32 approach". In this case, you might be able to stay at 3500' past HOTIN until intercepting the vertical guidance.
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@John Collins just weighed in on this here, post # 28 https://www.pilotsofamerica.com/com...ash-short-of-burley-municipal-airport.137623/
 
Salty said:
I guess I just don't care either way about his analysis since if you fly the approach as published (or even a bit more conservative) there is no issue.
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My questions are, if you are at the MDA, how far do you clear the towers, and is that enough clearance to provide a sufficient margin of safety?
 
With an RNAV (GPS) straight in approach, the requirement is for the MDA to clear the controlling obstacle by 250 feet. So with an MDA of 4560, the highest obstacle to the runway can't be higher than 4310 MSL. The runway TDZE is 4152 and from the white board in the video, he asserts the tower is 118 AGL plus another 20 feet above the runway or 4290. The FAA obstacle database shows a tower at 4256. In either case, the MDA is more than 250 feet above the tower. A non precision approach does not assure that the path from the MDA to the runway is clear of obstacles, it merely provides for safety at the MDA when in the clouds. To descend below the MDA, you have to see the runway environment and avoid any obstacles visually. Using the VDA is not guaranteed to avoid hitting an obstacle below the MDA.
 
I found it difficult to watch all the misinformation on the video. So many erroneous and unfounded assertions. He is simply generating a narrative that is not true and then fudging the results to match his narrative. At best, he is sorely misinformed, at worst he is dishonest, especially if he does not correct the video's errors.
 
Because this thread has some learning value, it might be good for future searches and forum users that the OP change the title of this topic (@LesGawlik ). Thanks for starting it.
 
Not perhaps in line with latest discussion here, but here's a refresh on some background. If you have time read the FAA's analysis of the stack which the a/c impacted at the link below. There are actually 7 stacks listed, but #1617 is the one in question here.

The items I noticed are (a) The stack was to be painted (it wasn't) and lighted (might not have been according to Gryder, who destroyed that evidence). If not lighted, then instrument approaches would be N/A at night (pages 6,7).

And, (b) the FAA letter says changes are required to takeoff minimums (page 6), departure procedures (page 6) and MDAs (page 4). Don't know if that was ever done.

The FAA may not have followed up on the lighting of the stack, since there's no note on the plate, or NOTAM making the procedure N/A at night. But we have to take Gryder's word for it that the light was inop.

https://oeaaa.faa.gov/oeaaa/external/letterViewer.jsp?letterID=321199198
 
Salty said:
I guess I just don't care either way about his analysis since if you fly the approach as published (or even a bit more conservative) there is no issue.
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Who do you fly for?
It does appear that the people who speak with the most certainty on subjects of aviation tend to have the least experience.


That approach shouldn’t exist in its current form right now. The letters even from the FAA show that there are major issues with the approach, this lady wasn’t flying her 182 in clear blue and 22 to get her 6 in, she was flying for hire in bad weather conditions most here wouldn’t drive in, let alone fly in, flew a approach that shouldn’t exist and had a bad outcome. Could she have done better, sure, could the FAA and town have done better very much yes.

Kyle N said:
I thought the same thing - that was straight IFR for almost the entire practice approach.
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The same video in the start of this subject?

That was visual, it was not first student solo weather, but visual, his camera skills do not appear that good, but most times he put the camera outside I could see the ground for miles, straight IFR isn’t dependent on weather, if you mean straight IMC that is not what it looks like.
 
Turbo-Arrow-Driver said:
It appears these multi-angle approaches, although described as "rare cases" in the FAA AC120-108, are not super rare. I just had a look at the O60 RNAV 32 approach (Cloverdale, Calif), and it has a much larger slope change. The descent angle from IF to FAF is 0.84 degrees (133 fpm descent rate @ 90kt), and from FAF to runway threshold is 3.50 degrees (557 fpm descent rate @ 90kt).

Extending the 3.50 degree slope all the way from runway threshold to IF puts you at 5000 MSL.

The GNX375 simulator will show you "on glideslope" at the IF -- HOTIN -- if you arrive there at 5000 ft, and will give you an constant descent angle all the way from there to MAP. I didn't try it, but the Garmin GTN units will probably do the same if you enable the "remove constraint" option for HOTIN.

This seems like something useful to know about how some Garmin GPS navigators work.
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There are no multi angle approaches if you are referring to the VDA and the LNAV+V. There are some approaches where the VDA or the +V is determined by the step down fix and not by the FAF, in which case, the GP passes above the minimum altitude at the FAF.
 
Turbo-Arrow-Driver said:
Actually, I meant -- why do you need the stepdown fix if you want a lower MDA -- but you answered it anyway, so thanks. It's most likely the stacks at the plant -- and that also explains why the first segment of the final approach is at a more shallow angle -- to clear the obstacles.

So next question -- why not just move the FAF (HIKLO) a bit closer to RW20 so that the entire approach is at the 3.75 degree slope? Something like 1/2 NM closer would do the trick. Does that make the final segment too short or something?
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Because it would no longer be a straight-in approach. My guess is if you move HIKLO closer you will need a steeper descent to get to MDA. The missed and MDA are typically not at the same point in space, that's a DA. You need time to see the airport on a NPA.

Another point comes to mind: An approach NEVER EVER takes you to the runway. No matter how low it goes. No approach I know goes to 0 AGL (maybe CATIII as someone pointed out but who cares). An approach sets you up for a visual landing. This concept took a long time for me to sink in, i.e. an approach give you a safe lateral and vertical (precision) guide path to get you down low enough to safely land VISUALLY. All this talk about Garmin vs Jepp and diamond thingy is IMO not really useful because it doesn't matter - it's all a distraaction. At some point, your eyes are going to be outside and that's where the danger lurks.
 
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Trogdor said:
...No approach I know goes to 0 AGL. An approach sets you up for a visual landing...
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I'm outside my area of expertise here, but what about a Cat III ILS? (Don't some airliners have autoland capability?)
 
Jackk said:
Who do you fly for?
It does appear that the people who speak with the most certainty on subjects of aviation tend to have the least experience.
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Yep. People who’ve never done the kind of flying she was doing haven’t an inkling of an idea what it takes.
 
Palmpilot said:
I'm outside my area of expertise here, but what about a Cat III ILS? (Don't some airliners have autoland capability?)
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Yes, there are still some restrictions though. But sure, I give you CAT III. Now back to reality for 99.9% of the folks reading this thread.
 
Trogdor said:
Yes, there are still some restrictions though. But sure, I give you CAT III. Now back to reality for 99.9% of the folks reading this thread.
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I don't know what the percentages are, but we have people all the way from zero to tens of thousands of hours on here.

But I admit that I get carried away with nitpicking at times.
 
Palmpilot said:
I don't know what the percentages are, but we have people all the way from zero to tens of thousands of hours on here.

But I admit that I get carried away with nitpicking at times.
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It's not even about time. it's about plane AND airports. How many planes are capable of CAT III approaches and have airports that support them. And again, there are still restrictions even in this case. I updated my statement above anyway.
 
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John Collins said:
There are no multi angle approaches if you are referring to the VDA and the LNAV+V. There are some approaches where the VDA or the +V is determined by the step down fix and not by the FAF, in which case, the GP passes above the minimum altitude at the FAF.
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Yeah. I think the point that's being made is that if you are not already established on the 3.75 degree VDA angle before you get to where the VDA starts, JAMID, and then changing angle to 3.75 it's almost a moot point. You're going to be on it for probably less than a mile before you get to MDA, where the VDA effectively ends. It does look like most GPS Navigators will help get you established on the VDA angle out by the FAF so you don't have to make the angle change where the VDA begins.
 
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