Part 2 - Modern Avionics and the Instrument Pilot - Part 2 Intercepting Final and the Missed

Discussion in 'Cleared for the Approach' started by wayneda40, Jan 11, 2022.

  1. wayneda40

    wayneda40 Pre-takeoff checklist

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    If you’re a current instrument student or an experienced instrument pilot upgrading from a 6 pack… modern glass panels open a whole new world of precision and automation. This short video series is intended to add some clarity to concepts and scenarios for using modern avionics in our instrument procedures. In this part 2 of the series we work the details on Vectors to Final approaches plus automation available to fly the Missed Approach. Welcome aboard! Wayne, GeezerGeek Pilot
     
  2. jrcox19

    jrcox19 Pre-takeoff checklist

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    One piece of feedback. The "Command line" you keep referring to is called the AFCS Status Box according to Garmin, for G3X. For the rest of the avionics world, it's generally called the Flight Mode Annunciator (FMA). This seems to be the FAA's recommended naming based on AC 25.1329-12. For a self proclaimed non-expert on Avionics, you seem to have a pretty good grasp
     
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  3. wayneda40

    wayneda40 Pre-takeoff checklist

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    @jrcox19, thanks for watching and I appreciate your taking the time to provide good info on the formal names for my probably-invented "command line" vernacular :).
    Wayne
     
    Last edited: Jan 11, 2022
  4. AggieMike88

    AggieMike88 Touchdown! Greaser!

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    The original "I don't know it all" of aviation.
    I call that line “the scoreboard”. A moniker taught to me by several airline pilots who are also active CFI’s
     
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  5. coma24

    coma24 Line Up and Wait

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    Excellent work, Wayne! I'm sure it's possible to get to the point where managing the automation feels as smooth as hand flying the plane, however it does seem like there's a valid conversation about the pros and cons of hand flying vs automation, specifically on the initial portion of the missed. I can see the value in having the AP handle the initial, intermediate and final approach segments, though.

    Under duress, I can see someone fumbling the change in modes and/or the correct sequence, especially if they're not super proficient. The outcome of the engagement of automation is binary....either you engage it properly, or you don't. Contrast that with hand flying which is an analog process. It's possible to be less than perfect while hand flying, but still on top of things (and correcting).

    Evidence of this is the last 10 years of involvement with the simulated ATC environment (with which you're familiar) where I've lost count of the number of times that we've pointed out a deviation to a pilot only to hear a sentence where one of the first three words is either, automation, FMS or autopilot. That is rarely the case with pilots who are hand flying. This is not to say that it can't be properly done with automation, of course, rather my point is that it's a less forgiving way of doing business.
     
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  6. midlifeflyer

    midlifeflyer Touchdown! Greaser!

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    I made a comment to Wayne on YouTube that I saw no reason to use VTF for the ILS but Activate Leg for the RNAV. That's not about "never use VTF," but the lack of difference in result for ILS vs RNAV and my personal preference for consistency where I can find it.I just do it the same way for both.
     
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  7. wayneda40

    wayneda40 Pre-takeoff checklist

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    Keith, thanks for the solid points about being dutifully careful about the automation. I totally agree, and I've come to follow what your friends at PilotWorkshops suggest about... if the autopilot does something you're not sure of, rather than instinctively disengaging it completely, drop the automation down a notch. In my case that means drop from AP, first to hand flying per the Flight Director, and if still not what's expected, (since I always keep the heading bug synced) drop down one more notch to HDG mode... and if that's not enough, well fly raw data and/or climb straight ahead and get out of trouble. You are totally correct that automation not well understood and thoroughly monitored is very prone to binary behavior (it's working; it's not working!) compared to hand flying.

    I harped upon this in the video (probably too much)... but I believe we can reduce automation surprises by being super diligent in continually confirming the status of the CommandLine/Scoreboard/FMA. That status of course fully determines the validity of the Flight Director, and thereby the Autopilot.

    On your point about automation in the Missed... I also agree. Upon clicking the Go Around button, the G1000 in my DA40 disengages the autopilot and puts the Flight Director into the GA Lateral and GA Vertical modes. That's cool and I hand fly to the Flight Director, but find it important to, within a few seconds, get the lateral into NAV/GPS mode as many missed approaches have early-on turn outs. On my friend Scott's Sling TSi (as in this video series) and also newer Cirri, the autopilot remains engaged after the Go Around button... however a reasonably swift change from GA Lateral to NAV/GPS remains an important step. In any event, a solid briefing of the approach plate remains critical so that the pilot "knows" what to expect (e.g. at 400' AGL, a climbing left turn on heading xyz to intercept radial abc, etc).

    This is such fun -- and important -- stuff! Thanks for contributing your piloting and ATC skills to the conversation.
    Wayne
     
    Last edited: Jan 12, 2022
  8. midlifeflyer

    midlifeflyer Touchdown! Greaser!

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    This is a good point. I have seen pilots rush to engage the automation resulting in putting themselves behind the airplane.

    Not with Wayne's GFC autopilot, but there is a big gotcha in switching to NAV mode with some other ones. I wish I had the video for one I demonstrated but the camera crapped out on me. It's an earlier model of Wayne's airplane with a KAP 140 rather than the GFC. The 140 does not have GPSS (it also doesn't have a TOGA button). It will, however follow the NAV course if engages within 2 dots of lateral. The result can be fun to watch. As you can see from the pic, the missed is a climb to 1300 (about 850' above DA), then a climbing left turn to 2100 to IKTOW for the hold.

    I think most people realize that without GPSS (and perhaps some other newer stuff), we need to wait until we get to 1300 before engaging NAV. But the gotcha is better than that. If engaged while still straight ahead, the 140 (as will many non-GPSS autopilots) will go to NAV mode and make the turn to IKTOW. But it will make the shortest turn. Picture imperfect pilot technique or a crosswind from the right when you engage.

    upload_2022-1-12_10-58-46.png
     
  9. wayneda40

    wayneda40 Pre-takeoff checklist

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    Wow, that's scary stuff! With older navigators and non-digital autopilots, I'd most certainly plan on hand flying the Missed, or at most put the AP in HDG mode and steer with the heading knob.

    In contrast, if anyone here hasn't yet flown behind a panel WITH a modern navigator and digital autopilot, I encourage you to find a knowledgeable CFII and a well-equipped aircraft and experience for yourself the very dependable magic that these systems provide (assuming accurately programmed and confirmed on the Command Line :)).
     
  10. coma24

    coma24 Line Up and Wait

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    Small aside, given the presence of the RNAV approach to the same runway with LPV minima, I'm curious how many pilots would prefer to shoot the ILS over the RNAV?
     
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  11. coma24

    coma24 Line Up and Wait

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    Wayne, I remember seeing a very old video on YT by an airline captain about stepping down the automation levels. I bring a bias to the discussion as I've basically hand flown the Lancair for many hundreds of hours at this point, but I keep coming back to the AP being a solution in search of a problem when it comes to the approach phase of flight.

    I have recently forced myself to use it for extended periods enroute to see how it feels, and I do see some utility there that could lead to a reduction in fatigue on long enroute segments, however I'm yet to think of a case in all the years I've shot approaches in IMC where I have found myself thinking, "wow, this would be easier/safer with an autopilot."

    I do not possess any stick and rudder skills that others do not. People with amazing stick and rudder skills, in my mind, would be military/civilian test pilots who have to fly very complex profiles with very little margin for error, often under constantly changing circumstances. I would also put professional aerobatic pilots (Rob Holland would be a very specific example) on that list. I'm proficient enough at flying an IFR profile by hand, staying on top of navigating laterally/vertically, being aware of my energy state and trend and staying on top of managing the GPS navigator. I struggle to understand what an autopilot is going to provide for me in the approach/departure phase of flight.

    In the spirit of honesty, I find this lack of understanding to be a failure on my part because I have come to learn over the years that very few people have the same attitude. Most people believe that increased automation with a reliable autopilot is the way to go. While my airplane does not have a highly capable autopilot, my sim certainly does, so I force myself to practice using it in that environment. I can click the buttons and watch it capture and fly a glideslope, but unless it also has auto land, I can't say I'm a fan of taking over at minimums and coming in 'cold' on the controls. So, again, I'm left with the same nagging question..."what is this ACTUALLY doing for me?"

    If the act of flying a heading/altitude was challenging and fraught with danger, then I think the answer would be right there for all to see, "this makes a hard task easier." However, I disagree with the opening premise, and I believe that the use of the system is unforgiving and requires levels of training/familiarization that aren't always there...and certainly not required to be there when you get your ticket.

    This would be such a fun topic to beat to death over drinks, sorry for clogging the forum with it, but I won't lie, this weighs heavily on me because I feel as though I'm being stubborn or inflexible by sticking with hand flying in the approach/departure phase. I'm very, very much open to having my mind changed....I just haven't heard the right argument yet.
     
    Last edited: Jan 12, 2022
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  12. wayneda40

    wayneda40 Pre-takeoff checklist

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    Good, important question. Maybe we'll need a Poll on this. Several PilotWorkshop IFR Mastery episodes have pointed out the rock-solid accuracy of RNAV LPV approaches (in contrast to interference-prone ILS signals)... and my limited experience supports this conclusion. Unless just practicing, I'd pick an RNAV LPV every time over an ILS with similar minima.

    Keith, a question for you on the ATC side: at least on the US West Coast most all the ATISs state "ILS Runway XY in use" and it seems SoCal & NorCal default to providing vectors to that ILS (when it matters on a given day, I'll request the equiv RNAV). I understand that we still have many non-WAAS aircraft flying approaches, but what are the considerations (more granular control of traffic?) that govern this default-to-ILS SOP?
     
  13. coma24

    coma24 Line Up and Wait

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    I've seen that progression mentioned before. I agree with the premise if the selected mode isn't doing what's expected, however, the transition to FD only (no AP) is there, in my mind, so you can verify which mode you're supposed to be in, and whether the navigator is set up correctly, etc. In other words, unless you see the AP struggling to do what the FP is commanding, then dropping to FD alone isn't going to solve anything....the core issue is, presumably, not producing the intended result due to a mode selection/configuration error as opposed to, "shoot, my elevator AP servo stopped working."

    Now you're hand flying, trying to ignore the FD guidance, and fix the command mode to produce the desired FD output. This is PRECISELY what we saw in the Pilotworkshops IFR bootcamps years ago with scores of pilots getting some small aspect wrong of the AP programming. Their workload went through the roof and almost always ended up deviating from the cleared route. The small percentage of people who were hand flying tended to not have said issue.

    One caveat to this would be the part 121 environment. The systems in those jets appear to be highly standardized, well maintained and more to the point, the pilots receive better initial training in their use, and are using them day in, day out. So their level of proficiency with those systems is well above a typical GA bug smasher who is flying for fun or occasional business travel.
     
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  14. wayneda40

    wayneda40 Pre-takeoff checklist

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    @coma24, darn it :), you continue to make such logical, solid arguments in support of hand flying!
    I don't really have a defendable counter-argument in favor of automation. For me as an admitted techie, I just enjoy learning about and becoming reasonably proficient in the logical and technological aspects of the avionics.

    Keith, just for fun, try this emergency scenario on the sim (I've done this many times, with the X-Plane stock C172/G1000 and TorqueSim SR22): try hand flying an RNAV LPV to raw data (no Flight Director), in zero/zero, where you HAVE TO land. Now fly that again with a digital autopilot, leaving the AP on all the way to pavement simply gradually pulling back power to induce a pseudo-flare. Rinse and repeat each method a few times. I'm quite certain I know which method is more reliable. OK, this is (maybe?) far-fetched, but still interesting to this techie.
     
  15. coma24

    coma24 Line Up and Wait

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    Hi Wayne, great point on the 0/0 case, I will concede that. However, that is also why my previous argument said, "...but unless it has auto land..." :)

    I will also give a little and say that in really challenging weather, I imagine there might be a workload reduction to be had in having a solid autopilot handling lateral and vertical during the final approach phase, which is ok if the transition from AP to hand-flying goes smoothly once the field is in sight AND the plane is trimmed correctly.

    Speaking of trim, if the AP was engaged during cruise and has been steadily adding back pressure the whole time as you've slowed down during approach, then when you disengage the AP, isn't the nose going to drop like a stone? I know C172's have the 'add trim' light to warn you of this case but I'm guessing it's not consistent across setups. Just another concern to add to my list :)
     
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  16. coma24

    coma24 Line Up and Wait

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    This is a case where my simulated ATC experience doesn't add much value on this specific real world issue. As a pilot, though, I am guessing there are 5 issues at play:
    1) change is hard.
    2) the number of GPS-equipped aircraft who are NOT equipped to fly an ILS is far, far less than the number of aircraft who can't fly a RNAV approach to LPV mins
    3) until we move to ICAO flight plans being mandatory, FAA flight plans still exist, and aren't granular enough in their equipment suffixes to definitively tell you if a plane can fly to LPV mins (/G isn't enough info)
    4) there's no advantage from an ATC perspective that I know of to favor the RNAV over an ILS. Actively using both can be problematic in some cases where the missed approaches are different as you now have to routinely protect not one, but two missed approach procedures.
    5) this is kind of of mixed with #2, but until WAAS IFR GPS navigators become mandatory for any IFR flights, then it likely doesn't make sense to publish the RNAV approach as being in use for a given runway if it's also served by an ILS.

    These are all educated guesses, nothing more. I would love to hear someone with controlling experience chime in on this one.
     
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  17. wayneda40

    wayneda40 Pre-takeoff checklist

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    I'm guessing it depends on the autopilot/servo combo. Unlike the analog autopilots I've flown with (STEC, Century) that complain about "trim up/down" that the pilot has to manually adjust, in the GFC autopilots there is no such thing... and when transitioning to hand flying I've never noticed a significant pitch up/down prior to me physically moving the stick.
     
  18. RussR

    RussR En-Route

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    Not directly related to the question, but ICAO flight plans are mandatory and have been since Aug 27, 2019.

    Source - many, many aviation news websites and the FAA website.
     
    Last edited: Jan 12, 2022
  19. midlifeflyer

    midlifeflyer Touchdown! Greaser!

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    Given a choice and similar minimums, I'm LPV rather than ILS.
     
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  20. RussR

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    There's not even a debate for me. RNAV every time.

    Unless it has higher minimums and the weather is bad enough for that to matter.
     
  21. midlifeflyer

    midlifeflyer Touchdown! Greaser!

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    Yep. Since I fly with both setups (and others), there is some initial similarity since your TOGA setup disconnects the autopilot. And this actually applies to many setups - both gas and glass.

    In both of our cases, the initial step is to manually cram/climb/clean. TOGA gives the advantage of a flight director, but the act is the same. Once the climb is established, in both cases, turning on the autopilot captures the existing pitch and roll. Up to that point both can be flown the same, although the FD is a definite advantage.

    It's the next step where the difference occurs and it's about GPSS. When GPSS is the NAV source (as with the GFC autopilot and any GPSS autopilot) , the airplane will make the turn on course in the appropriate direction. Without it, the choice I teach is HDG until on an intercept to the course.

    It's really not a big deal. A pilot who flies with a setup gets used to its idiosyncrasies. The problem comes up when pilots fly multiple airplanes with different setups. I fly with so many differences (including HSIs which don't auto-slew :eek:, I literally have a page in my personal checklists which comes down to -here's is how this one works.
     
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  22. coma24

    coma24 Line Up and Wait

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    Russ, I'm happy to be wrong on that one! They had planned and deferred the roll out so many times, it seems, that I failed to notice that they actually had it stick this time. I moved to ICAO plans a long time ago with ForeFlight and failed to notice that they actually pulled the trigger on the mandatory rollout.
     
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  23. John Collins

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    The latest version of the AIM has this major update:

    The AIM also created Appendix 4. FAA Form 7233−4 − International Flight Plan and Appendix 5. FAA Form 7233−1 − Flight Plan and which say respectively:
    Since you are a user of ForeFlight, the setting for the default form, ICAO, Domestic, or same as last flight plan is long since gone from the App. Also the form Type can no longer be changed from ICAO, unless you have the military version.
     
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  24. John Collins

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    A lot of pilots still don't know how their particular autopilot and or the GPS interact with each other, even if they own the airplane and only fly the one they own. Not well understood is when to activate the missed approach guidance when there is a turn and in particular a climb and then a turn. This can be compounded by the typical installation where baro-corrected altitude is not available to the navigator. Also there are differences in how GPSS works in conjunction with VLOC that can further complicate matters.
     
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  25. NealRomeoGolf

    NealRomeoGolf En-Route

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    My autopilot only flies fully coupled to ILS. So if I prefer to do a fully coupled approach I'd go ILS. Otherwise I prefer LPV.
     
  26. WDD

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    Good, basic overview of the overall construct. Thanks for posting!
     
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  27. wayneda40

    wayneda40 Pre-takeoff checklist

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    @WDD , thanks for watching and I'm pleased you enjoyed the video.
    Wayne
     
  28. asicer

    asicer Final Approach PoA Supporter

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    ATIS said ILS approach was in use so I asked for that when ATC queried me. In this case, it didn't matter since it was pretty much the same approach/minimums as the LPV and I was getting vectored to final. Otherwise, I prefer LPV.
     
  29. midlifeflyer

    midlifeflyer Touchdown! Greaser!

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    Most ATIS airports still advertise the ILS when it's available. But advertised doesn't prevent a pilot from asking for the one they want. ATC will generally accommodate the request.
     
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  30. asicer

    asicer Final Approach PoA Supporter

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    Yeah, I know. But for this particular approach on this particular day the difference was really quite negligible. The fact that it was advertised over ATIS was the only tie-breaker.
     
  31. Trogdor

    Trogdor Pre-takeoff checklist PoA Supporter

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    All minimums being equal, why the heck would you ever fly an ILS over an LPV? LPV is less workload, more accurate, and achieves the same thing. What am I missing?
     
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  32. wayneda40

    wayneda40 Pre-takeoff checklist

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    @Trogdor, I totally agree. For reasons that aren't clear to me (bureaucracy?), it's often the case that the minimums for the LPV are a bit higher than for the ILS. Perhaps someone can fill us in on why.
     
  33. WDD

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    LPV would require international certification to be a “precision” approach. As quickly as so many have been created it would swamp the FAA even more to do that. So while they are as good or better than ILS, they are not “precision” and thus I guess can’t have the same or lower minimum as a “precision” ILS.
     
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  34. RussR

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    I wouldn't say "often" anymore, typically they are the same now at locations that have both. In the past, it was most often due to one of the following:
    1) When LPV started, it was limited to 250 HAT by policy. Early days, "baby steps" I suppose. So even at major airports with highly-cared-for clear areas and perfect lack of obstacles, the ILS would be 200 and the LPV would be 250.

    2) For years after LPVs were introduced, the missed approach required them to go straight ahead for a certain number of miles to a waypoint, then the path could turn, but only 90 degrees at a time (or 120 degrees depending on when it was designed). So if there were obstacles a few miles off the departure end, the ILS could just have a "Turn right direct (LOM)" or some other version of a fairly immediate turn, where the LPV would have to go straight ahead and couldn't avoid the obstacles. So the DA would be raised to compensate. If you are looking at a procedure where the missed has several waypoints used just to get the airplane turned around (example - KGJT RNAV (GPS) Y RWY 11), it most likely was originally designed back in the early days of LPV.

    https://skyvector.com/files/tpp/2113/pdf/00634RY11.PDF
     
    Last edited: Jan 14, 2022
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  35. wayneda40

    wayneda40 Pre-takeoff checklist

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    @RussR, thanks for the details -- and improving good news -- about the LPV minima!
     
  36. NealRomeoGolf

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    Can an LPV now turn 180 to go back or still have to go in stages?
     
  37. RussR

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    Yes, current design standards do allow a "climb to 1800 then left turn direct XXX" type of missed, where the XXX is directly behind you (or anywhere).
     
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  38. John Collins

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    Also, many LPV/ILS locations may not have been updated to the current standards, including missed approach procedures. Particularly on the West Coast, LPV200 can be more problematic verses standard LPV with a 250 or greater DH due to more stringent vertical integrity requirements for LPV200 (VPL of 35 meters vs 50 meters for LPV), so in areas on the West coast with a generally poorer WAAS vertical integrity, there are more outages if one establishes an LPV200 procedure verses a standard LPV. This may have reduced the number of LPV200's. Here is the last quarter number of outages for LPV (none) vs LPV200 (quite a few). Which would you rather have 250 DH for sure or 200 most likely? You can choose both.

    LPV Outages 4Q 2021.png

    LPV200 Outages 4Q 2021.png
     
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  39. wayneda40

    wayneda40 Pre-takeoff checklist

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    @John Collins, again, solid useful info! Thx.
    Flying in the US West, with those outage rates, I'll happily take LPV250 :).