The Difference Between LPV and LNAV/VNAV Approaches: Boldmethod Live

[Music] [Music] [Music] [Music] [Music] [Music] [Music] [Music] [Music] [Music] [Music] [Music] [Music] [Music] [Music] [Music] [Music] [Music] [Music] [Music] [Music] [Music] [Music] [Music] [Music] [Music] [Music] [Music] [Music] [Music] [Music] hi I'm Alex Idris and thanks for joining us tonight for bold method live IFR we're gonna talk about our nav procedures and hopefully clear up some concepts like RN p and l pv l Navi nav and L nav and kind of help us understand what we're looking at when we look at a chart and this is going to be to like looked at from the pilots perspective not a procedure designer perspective but something that we can use when we actually pull up an orang AF procedure in the cockpit tonight we've got Cori chimeric managing her chat so as I'm going through this presentation if you have any questions or if you want me to go into more depth throw a question out there and chat Coryell grab it and forward it over to Colin Cutler who's our technical director tonight he'll work it up on screen don't wait for the end throw questions in all the way throughout the presentation makes it a lot more interesting ok so we're going to start tonight by looking at performance-based navigation or pbn and then we're going to start to distill that down into the difference between our nav and our NP and where GPS ties into all of this and then we're going to look at those different lines of minima and nav specs and and understand where all that comes from and then we'll look at how our aircraft use that and then finally we'll talk about what happens if we lose our nav capabilities while we're flying an our nav approach procedure that last part is something that we occasionally get an email question on but many people really never think much about and you really need to what happens if your aren't enough capability downgrades is you're flying a procedure what's going to happen so we got a couple videos at the end to demonstrate what would happen in a g1000 and exciting we can relate that to a lot of other aircraft as well ok so let's start with the question what is performance-based navigation and the graphics Department has worked up a fabulous slide that tells us a lot about that this is my favorite slide of the entire presentation calling you want to cut to it right right here that's what it is so if people think I'm reading from the iPad when I'm doing this I'm not cuz right now it doesn't help me performance-based navigation is a new concept for our nav and by new I mean new in the world of aviation not fifty years old and so when we started to think about our nav most people think about GPS GPS is our nav but some people who might be in their early 40s remember days of flying course line computers where you could use vor and DME to kind of airy and navigate and not go directly to each one of those spoken hug vo ours that also was a form of our nav and some of us remember Lauren which was ground-based system fairly similar to GPS not an operation but in service and that you know itself was a type of our nav so we talked about our nav it actually extends back quite a while ships have been using Lauren for a long time our nav is just simply area navigation the ability to navigate through an area without going to specific ground station points that's what our net is it means that you don't have to fly to a station and then track outbound and do this kind of dogleg radial thing area nav means that we can go pretty much anywhere and it's been around forever and then in the 90s GPS showed up and if he came certified for aircraft in the mid to late 90s but we didn't have a full concept of how it would change the National Airspace System so we started to integrate it laterally as kind of a okay you can use this but you need to have backups and eventually that is evolved into our modern GPS based system where we've got GPS satellites telling us our position and then space-based augmentation Espace which we call wide area augmentation in the United States or wasps those satellites giving us information to make our position really really accurate and in some case even ground-based augmentation for certain airline operations that they're testing out where you using ground-based transmitters to make that position ultra accurate all of this has grown out of this old concept of our Neff and so because of that the FAA has come up with a concept of performance-based navigation and essentially what we're trying to do with pbn is allow aircraft to fly a three-dimensional path through the National Airspace System and allow aircrafts of varying capabilities to fly varying paths requirements so essentially based off your aircraft's avionics performance capabilities there are certain procedures and paths that you can fly and others that you can't that's what pbn is it's kind of this umbrella for everything our nav and again it's easy to think well yeah our nav is all GPS now not so you've got DME DME rnf on some transport especially older transport category aircraft and some business jets where you use two or more DME facilities to triangulate your position you could have inertial reference units ring laser gyros inertial reference systems that basically start out with an own position on the ground and spin up and then essentially track the aircraft's acceleration as it flies and come up with a predicted position you know before we had GPS over the ocean that was one of the ways to get an idea of where you were its accuracy degraded over time but it can usually get you into where you need it within a few miles all of these are still out there in the National Airspace System and if you look at a modern airliner it's not just using GPS it has GPS possibly it might have lost though not all of them do but then it may be backing that up with DME DME information VHF formate information so our nav isn't just GPS its GPS plus all of the other technology that we have developed over time to help us figure out where we are without going directly to a ground-based nav station okay so that brings up the concept of RNP or required navigation performance and that we actually have a really good slide for okay so RMP is a performance based navigation system that includes onboard performance monitoring and crew a learning capability and the aircraft needs to meet the requirement or for an aircraft to meet the requirements of performance-based navigation a specified our nav or RMP accuracy must be met 95% of the flight time okay so pbn it says essentially RNP required navigation performance includes two very important parts the ability for it to autonomously monitor the system's performance to know whether it is as accurate as it needs to be okay to be able to say yes I know right now I can guarantee you that I know my position within a mile or 0.3 miles or 40 meters okay it autonomously can figure that out okay and then the second part is that if it realizes I can't guarantee that I am within 30 meters or 40 meters or 0.3 miles of where I think I am I can't guarantee that I don't know I'm wrong but I can't guarantee it anymore then it needs to be able to alert the crew so that the crew can come up with alternate navigation procedures to navigate through the National Airspace System so those two very important points and we think about that going back to old-school GPS when they first started installing the aircraft the original garment for 30s that did not have loss we have rain right receiver autonomous integrity monitoring its autonomous we don't need ATC to help us we don't need ground base stations it works because the receivers got extra satellites and is just double-checking its position and rain allows for crew alerting if rain detects that the position is bad or if rain doesn't know if the positions bad it just says well I don't know enough satellites anymore to double-check the position it could be good it could be bad either one of those two cases it no longer meets pbn requirements and it could alert to you and so that's essentially a pbn system when we talk about are and aren't an RNP system Assoc say we talk about our MP versus our nav the way you can look at it is our nav doesn't necessarily have the ability to tell you that it it's no longer accurate our nav doesn't know how accurate it is and our NP can verify its accuracy and if it for some reason can no longer tell its accuracy it alerts you so a way to think about that rain or wasps that's our MP if it ever loses its position or loses as it loses its ability to verify the position it shows you a message an alert box ring laser gyros on an inertial reference system on an airliner built in the 80s those as you spin them up on the ground they know their exact position that's picked up it takes a long time for those to spin up as they start flying that accuracy starts to degrade they don't know how much that accuracy is degraded it's it's who knows so that would be an or nav system it doesn't know if it can maintain accuracy it just has a guess in a position okay and again for an aircraft to meet the requirements of pbn a specified or dev or RMP requirement must be able to be met 95% of the flight time okay so that brings up the concept of nav specs I'm gonna show you a chart that most pilots really don't ever look at but you can see we have both are to have specifications where the system can't guarantee its accuracy it needs someone like ATC to monitor or RNP where it can self monitor its position and we have different standards and so these are in generally in miles here with the exception of where we put an M for meters and so you can see we have each we have all these different nav specs here on the side our nf2 our nav 1 RN f 2 RN p 2 RN p 1 RNP approach advanced RN p RN p authorization required approach and then a couple others we'll talk about those in a different video but when we start talking about the national air space system and what we're flying in ok we either be rnf 2 or 1 RNP 2 or 1 because that's going to cover in route domestic operations are terminal arrivals feeder routes and terminal areas and then RNP approach both the initial segment the intermediate segment so 1 mile RNP standard one mile RMP standard in the final approach segment which is either 0.3 miles or could go down to 40 meters and then the missed approach segment which would be again another one mile RMP okay so what is this chart have to do with real life especially on an approach when you fly a a our nav procedure and our nav approach procedure in the US National Airspace System you're flying an RNP approach even though it does not say the words or NP in the title and this is really confusing because someone's going I've seen procedures it's a aren't have are NP RS AR to have GPS absolutely if it wants to keep you on your toes we use different naming conventions in different charts but essentially if you're out there and you're serious or Cessna or 172 and you're flying with an IFR certified GPS unit okay a 434 30 W g1000 g1000 and X I avid ein any of those IFR certified systems you're flying when you fly an approach procedure you are flying an RNP approach and so the system throughout that entire procedure needs to be able to verify its accuracy ninety-five percent of flight time so when you go back to that all sudden that makes sense so like yeah rain or wasps which always provides that verification okay that makes sense to me so we're when we fly an RN Ave procedure it's really an RNP approach okay so where this can get confusing and we're gonna look at this in detail we'll go back to the slide for a second is this procedure right here the RN p a our approach okay in light aircraft or when we're flying a procedure titled RN p GPS what were used to or sorry are now a thank you or have GPS I can either get confused our nav GPS we are flying an RNP approach when you see those procedures titled our nav and in parentheses are NP then you're flying an RNP authorization required approach the difference between these two is aircrew and aircraft certification and training the authorization required receipt procedures require additional training and certification so that aircraft can safely operate in close proximity and typically you see those in new airliners you're not going to see them in older airliners 145s typically don't have them older CR J's you're not gonna see them there but if you start to look at the new airliners is 787 the Embraer 175 some of those you'll find those equipped to fly the RMP authorization required approach and again it's not just the aircraft the aircrew needs to be specially trained as well so people go would that be limited to the airlines no if you could afford the equipment under part 91 and you want to go to flight safety or CAE and take the training absolutely then you could also get approved by the FAA to operate on those procedures and a lot of business operations do okay we're gonna talk about that in more detail in just a bit but the key thing I want you to remember the takeaway here is even though in light aircraft with basic IFR GPS or wasps GPS equipment we're still flying an RNP approach okay let's talk about some minima I think everybody's seen these on approach procedures these are the different types of guidance and there's a reason why we have them laid out this way we have lpv okay or localizer precision with vertical guidance we have L nav V nav which would be lateral navigation and vertical navigation we've got L nav which is just lateral navigation and we've got up here LP which is just localizer performance so essentially each of these require different RNP capabilities okay essentially they would require a the LP vs and the LPS require the most precise level of RNP all the way down to that 40 meters L Navi nav requires less precise RNP capabilities and L nav is essentially the same RMP requirement as L Navi nav it just doesn't include the V nav part okay so when we think of this an LP v really is basically a GPS wasps driven ILS a lot of people get very confused about what an L Navi nav procedure is and here's a way to think about it originally when they came up with a concept of L Navi nav and this is going back even before waswas in the system you had transport category aircraft which did have GPS with bait with rain so they could fly an L nav procedure but they also had flight management systems and advanced static systems and naked commute or compute a barometric glide path they could use the GPS basic GPS even with rain right monitoring is not accurate enough to give us a vertical glide path but with a with the right computer technology and a tap into your static line you can use that barometric system to create a vertical path so that's what we call Baro V math and you'll hear this term kind of an in charts and in aviation Baro vena have means that we're using a flight computer and not an e6b but like your avionics either a flight management system or a newer avionic system and that's tapped into the static system it's just using the change in pressure to draw a glide path it's not using GPS or or nav at all so as we started to create GPS systems what we said is okay well if you have a garment for 30 you can fly Elna minimums but if you're flying this transport category aircraft of this complicated FMS we could build something in there that can draw this V nav barometric path will create L Navi nav well now that's all changed and many aircraft including like a modern g1000 or a g1000 nxi unit are oftentimes equipped with the same logic so they also can compute that same barometric v nav system and so we can really think of these as fall backs so let's take a look at that chart again lpv requires the most level of RNP precision if you're not equipped for it or for some reason the receiver can't guarantee that level of RNP maybe there's a wash at a light out then you can fall down to L Navi nav a lower level of precision however this V nav in most cases would need to be barometric ly ate it or Barrow V Neff and then finally if you don't have Barrow vena have capabilities and you were to not be able to maintain LP v you would end up falling back to L math that would be the lowest level of precision the least accurate level position that you could fly you'll notice LP is kind of off here on its own and there's a reason for that LP is not a fallback from LP V okay LP is its own procedure it's a procedure designed when a vertical glide path wouldn't be possible due to obstacles we'll take a look at one of those into Colorado but people get confused they look at LP V and they go if I lose something can I fly an LP no they require essentially this they require the same RMP value so they're not a fallback it's just an LP V think of it as an ILS okay if the obstacle clearance planes permit we can fly an ILS n that's the most accurate but in some airports like veil or Telluride we could put a localizer in there but we can't give you the glide path there's just too much terrain around there and so the same thing happens in the GPS world we can put an LP in there and if the aircraft can't guarantee the RMP requirements for lateral oka Lizer precision minima then it falls down to L nav so back to the slide think of this is a fall down system in a modern wass enabled aircraft use start at lpv the receiver is capable of flying lpv minima okay but if it doesn't have the RMP that's required for lpv it will fall down and then it can fall all the way down to L nav okay so let's take a look at what you need LP v and LP require wasps but wasps is also capable of creating an L navi nav path and wasps can fly in L nav only pass path let's say you do not have a wasps enabled system you've got basic GPS with Berra waiting you cannot fly LP v but you could fly L Navi nav and you could fly L nav and then finally if you're only equipped with basic GPS and rain you cannot fly LP v or L Navi nav you would only be able to fly L nav so let's take a look at a procedure this is the our nav GPS to runway one seven left its Centennial Colorado and if you look at the procedure minima here you can see LP v get you the lowest L to have V nav get you not quite as low and then L nav gives you the highest straight in minima and then this circling to land minima over here essentially again the receiver will show L nav L Navi nav or LP v but the circle and minima is essentially always higher than L nav it's worse than L nav and you just artificially level out so essentially when you load a procedure your your GPS system your our nav system is going to look at what our NP value it can give you both what it's capable of doing and what satellites and information it has and it will choose the best RNP solution the most accurate which is why when you go to load an RNP procedure in the database it usually does not say L Navin have RL it always typically says if lpv minimums are published it says lpv it always typically says the lowest level of minimums so one of the things that we tip off intime z' is well okay if i don't want to fly an LP v how would i load it up is in l navi nav or just in l nav and the answer is in a GPS system and a modern gps system you can't you would you can just choose to fly to those minimums and level out if you want that's totally acceptable but the receiver is going to choose the best possible RMP solution that's what it's looking for so if you were to see a procedure that had LP v minima but the only thing you're maybe you're serious with Vera weighting is giving you is L Navi nav it's because you probably don't have wasps right now you're just down to basic GPS that wasps satellite reception isn't there and so the system is smart enough to say well the only option here the best option I should say not the only the best option is L naveen F and if you're to load up that exact same procedure from the database in an aircraft that has just a basic GPS unit so if you load up this aren't have to runway one seven right and or one seven left its Centennial with just a basic IFR certified GPS unit the only minima that you will see next to the procedure name is L nav because that's all that it can do so again when people get confused how would I fly to these other minima the receiver always selects the best minute minima available for the procedure and if you wanted to fly to lower minimum maybe for practice the reality is you could artificially level out early but there really isn't other than going into the system setup and turning off wasps there isn't a great way to get a receiver in operational use to step down okay let's take a look and this is this is it in a JEP chart let me show you quickly in an FA chart if you're using FA charts you can see it right here they write those minima across the side so here we've got L PvdA L Navi nav da and then the L nav MDA and then again circling is its own thing you know the receiver itself will still indicate its best possible RNP solution you're just gonna level out at that circling minima and and that's going to be your lowest altitude essentially your MDA okay I said not every procedure will have all of those choices so this is the I'll show you here the RF GPS Zulu to runway nine in Telluride so there's something that you should kind of pick up right away it's got a Zulu as opposed to just aren't M GPS to runway nine and if we end up with a Z that means that we're gonna start counting backwards and letters because we have multiple our nav procedures to the same runway okay remember if ABCD if we start with alpha that's a circling procedure but if we start with Zulu and Yankee and count backwards that way it's a straight end procedure it's just going to there's multiple procedures using the same navigation equipment that are going into that runway so at Telluride we actually have two are now have GPS procedures published we have the RAF GPS Zulu to runway nine and the Yankee to runway nine if we look back at the iPad you can see why so first of all obstacles prevent us from using from using a glide path so it is just a localizer precision LP procedure there is no fallback here though for El Navi never l nath okay there's no L have option and the reason is because of the sorry the lower I'll stay down here the lower minimum descent altitude L nav wouldn't give you and it's not just that even the the segment altitudes L nav would not give you acceptable protection on the final approach course considering the altitude that you cross setna at and then the minimum descent altitude that you can did you that you continue down to so here you cross the final approach fix at twelve nine and you go down to ten six forty and the the requirements for the procedure say the only R&P accuracy that would let you safely to send that of 12:9 and get lower would be LP and then also possibly safely fly the missed approach procedure okay so then we can look at the Yankee and you'll notice we have a different final approach altitude we cross the final approach at a different altitude hundred feet higher and now we have three different minima so we have LP if your receiver is able to get loss and guarantee that it has that RMP standard and then you'll notice no L Navi nav because vertical guidance do two obstacles wasn't available in this procedure so we just have L nav we have two of them here one has a box note and if we look at that that's at the bottom so I will highlight that as you read it mr. pro cars a minimum climb of 380 feet per nautical mile to 12,500 if you cannot maintain the 380 feet per nautical mile to 12 v on the mist then you would need to fly to this L nav requirement right here 12,000 or sorry yeah 12,000 140 feet MSL that's your newer there your new MBA okay so the concept that I want you to keep mind again what everybody gets confused about is I've got all these minima which one do I use well your GPS perceiver or your avionics system will give you the best RNP minima that it can fly and then when you look at the chart you'll need to determine if there are any missed approach climb requirements or climb gradient requirements that you need to meet and you'll find the minima that both your onboard aren't half procedure can do or receiver can do and that you meet all of the approach requirements like you can make the required missed approach climb gradient that's what you'll end up flying to and keep in mind you know you may anis may up an end up in a situation where LP requires a climb gradient that you can't meet so the receiver saying LP but you're still leveling off and an L MAV minima because it has a lower missed approach climb gradient that would be just fine again the receiver is always going to pick the best that it thinks it can do and it's not going to consider any other climb requirements or anything like that okay so we talked a little bit about the fact that this is a RNP approach right it's categories is an ICAO or MP approach but if you look at the header the header says our nav GPS never says the words our MP in there but there are procedures that do say our MP so this is rifle Colorado this is the our nav RNP Zulu to runway eight again the Zulus a hint that there's another RN or our nav procedure to runway eight okay it would be Yankee we'll look at that in a second but when the FAA puts or Jepsen puts RNP in parentheses what they really mean is that this is an RNP a or approach it's a authorization required approach so if you're flying with a 5:30 or an Abba dine unit or G 1000 thousand nxi and you tried to load the our nav Zulu you find it doesn't load up from the database now probably was in the database that's sitting on the system but the system knows that it's not certified to fly RNP AR approaches and so it will not offer you the procedure and so that's the key when you see the words R and P in there what it really means is that it's an RN PA our RMP authorization required procedure and that you can't fly it okay so the question we get every once in a while is why did they name it like that if you have our NP and RN PA our procedures why don't they say that on the chart that way make a lot of sense right well there's a couple problems the coding of the database predates this concept of RN PA are we've been using the term our nav for years so what if we switched all of the RN f procedures to be called R NP the FAA and the stakeholders said that's going to be really really confusing an ATC thought it would be very very confusing as well and then of course the concept of changing the database specs and changing the equipment because some of this is hard-coded in the equipment so that they can correctly say RNP that's not necessarily very practical either so what the FAA came up with essentially is yes they're both R and P procedures ones are in P the other ones are NP authorisation required but it's just easier to call them RNAV and we're going to use the information in parentheses to tell you whether you can fly this using your basic GPS r NP system or whether it's authorization required and if it's AR we're gonna put our NP in the parentheses with that you'll notice ATC never says GPS or R NP when procedure clearing you for the procedure and that's because essentially it's just an Arnav procedure so if they were clearing you will go back to this procedure right here on the iPad if they were clearing you for the Arnav Zulu to runway 8 they're not going to say RMP in parentheses they're just simply going to say United 23:48 cleared for the Arnav Zulu runway 8 into rifle Colorado they don't even worry about the fact that it is an RNP okay let's look at the parallel approach the r NP or our nav yankee aren't I have Yankee to runway same Airport this is the second approach the Yankee and you'll notice this one is set up for GPS and so you'll typically see that if you see an R NP procedure to a runway you'll typically see a parallel GPS or non our NP AR procedure to the same runway and the way ATC differentiates it is just by the letter it's an RNA of Zulu or an RNA of Yankee and the order depends on which procedure came first if the if the basic procedures the basic r NP procedures came first then they might be the zulus and the RMP a ours might be the Yankees they're just created in the certify anymore order okay and this is another good example if we go back to the iPad you can see there is only L nav minima published for this procedure this is again the RNAV GPS Yankee to runway 8 this is a procedure that you could fly using it IFR certified GPS system whether it's wasps or basic GPS but if we go down there and look at the minima will notice there's no wasps minimal limit listed here there's no LPS there's just an L nav why would they do that essentially there's if the localizer precision or the LP minima don't give you any extra obstacle protection that would allow for a lower MDA or visibility requirements they're not going to publish it they'll just simply publish L nav and that's what happened here when they looked at the different certification requirements for the LP minima and the L nav minima they found that they both end up with the exact same nd am das and visibility requirements so in that case they're just published l nav and if you were to pull up this procedure in your database it would show up as L nav okay let's talk a little bit about sup looks like we got a question okay we a should we have a ton of questions and a lot of them are really going to tie into where we're going right now but we're gonna start off with mark and he wants to know this when I turn on the GPS or when I'm flying one of these approaches what messages am I looking for to ensure proper coverage and performance okay that is a fantastic question first of all there's two places you should always look on a GPS IFR GPS procedure a receiver number one is you want to check the sensitivity or scaling on the procedure and you'll know if you look at a typical wha space procedure it'll turn into a receiver you'll see term displayed for terminal and then that will change into either l pv l navi nav or l nav that's the first place you want to check you want to check the it's changing at the appropriate places along the procedure and as you're flying down final approach you also want to include that in your scan because if the approach needs to downgrade where you lose signal that's going to show up in that kind of scaling or people call it sensitivity table okay that that message the other place you want to watch is your alert so I see the slot when you're flying the g1000 or a glass panel aircraft there he always seems to be an alert flashing at the bottom and people just ignore it I am to test saturator they say to go down there and check that alerts window bad news on an instrument approach because that alerts her messages window whether it's on a glass panel alert or just an alert on your GPS unit that is the other place that your GPS system will tell you if something is happening in it no longer can give you LP v or LP or L Navi nav performance criteria so we've got three videos that go through that and I'm gonna get to them in just a second and before we get to that I want to talk a little bit about scaling because essentially that'll help you understand what your receiver is doing as you fly down final we're not gonna get into the guts of the full set of scaling on a GPS procedure we're just gonna look basically at the intermediate to final approach segment and trying to keep this very simple okay so what I've got up right here is your typical wasps based scaling okay wasps based and you're noticing that I'm not saying the words L novena have LP v LP or L MAF I'm just saying wasps and that's because regardless of the minima that you end up flying to wasp based systems that have lost reception that have that that low level air that super accurate performance will essentially scale all of these procedures about the same way whether it's an L nav or a LP V and what they're gonna do laterally is they're gonna bring you in what we typically call terminal sensitivity plus or minus one nautical mile either side of center line until about two miles from the final approach so as we approach two miles to the final approach fix we're gonna start to taper that scaling down so that the scale full scale deflection of the CDI is plus or minus 0.3 so 0.3 either side of the center line at the final approach fix from there that's going to continue to scale down to about 700 feet at runway threshold and that's 700 feet total width so 350 feet each side of runway centerline okay that general rule is true for LP v LP and an L Navi never Elna variety when you're wasps based receiver has an appropriate wasps signal there's some little variations on LPS and LP vs they're meant to mirror a localizer and so they're not always 700 feet full full width at the runway that is kind of specially tailored it could be a little smaller it could be a little bigger depending on the airport okay so that numbers not really fixed it depends on the approach certification but it is a general rule it's going to be fairly close to 700 feet from full one side of the course to the other the other interesting thing about an LP or an LP V is it will never get wider than 0.3 nautical mile deflection on either side of the course so if you have a really long final approach like a 15 maybe 20 mile long final approach like a story it is a localizer would typically get way out there and final wider than 0.3 nautical miles either side of course but an LP or an LP V won't they'll keep you right at point three and tell that localizer style guidance would narrow to about 700 feet at the end okay that wasp based receiver when it's flying in L Navi nav or an L nav approach will do almost the exact same thing the difference is again we'll go back to the iPad it's going to scale up to plus or minus 0.3 right as you reach your final approach fix and then it will taper down to the 700 foot total with at the threshold there's some different criteria for it but really it's it's generally gonna be about 700 feet total with what I'm getting at here is simple if you're flying with a wasp ace receiver and you have wasps paced reception so you've got full wasps service you've got the wasps level of accuracy the scaling is going to feel for you the exact same whether the system is flying a procedure with LP V or LP minima or whether you're flying that procedure and rifle that only had L nav minima you're still gonna scale down essentially to that 700 feet left to right deflection okay looks like we have a question okay next up the question is this do you need to check Rheem if your GPS is equipped with wasps good question I'm gonna get into that in just a second but the answer is no wasps essentially replaces rain okay the wasp ace the wasps signal from the wasps satellites provide a different form of integrity monitoring and so therefore rain is already redundant it's taken care of by your wasp ace service however if wasps was out of service or was noted to be out of service during your flight even if you're like hey it looks looks like I got reception but I got a note I'm saying it's going to be out of service then you would need a check rain and so if you look at a wasp ace GPS system it also has the ability to go in there and do a rain prediction because if wasps isn't available or if it snowed immed to be unavailable then yes you have to check rain okay back to this let's take a look at the exact same procedure flown you know this if you look at this diagram we have right here this is a wasp a system flying either lpv LP or L nav minima it's all gonna look about the same but basic GPS scaling looks completely different no it's flying to the same L nav minima possibly that a watch receiver would use and that's because the capabilities of the system are different as we approach two miles within the final approach fix we taper down from plus or minus one mile one mile either side of center line down to that point three miles at the final approach Rick so that part's about the same what's different is we hold that point three nautical miles either side of center line all the way down to the missed approach point so again this is flying to L nav minima okay but if you were flying this exact same procedure to L nav minima with a wha space receiver and it had wasps it's going to taper the scaling in as you go so the important thing to keep in mind is depending on your equipment and whether or not it has wha space service the scaling could change on an elm a ver el novena procedure a wasp a system will give you more tighter scaling and so that's why I feel like man I've got out there and I've flown L to have procedures and I flown LP and I've flown LP procedures and outside of the glide path they all seem to feel the exact same to me that's because every time you flew them the receiver probably had full wasps coverage and so it was essentially scaling them all the exact same way okay next question okay next up we've got a question about this GPS approach that we're looking at Centennial and the question is this why do you LP V and L novena have have decision altitudes instead of MDAs even though they aren't considered precision approaches this is I know I say every question is a great question this is a fantastic question because it confuses everybody okay and you're right it it isn't a precision approach an RF procedure our nav GPS procedure is not a precision approach and if you learn to fly what I did or earlier in the 90s precision approaches always had DA's decision altitudes non-precision approaches always had minimum descent altitude that concept and terminology has stuck with us even though it is no longer valid and so it's you'll still hear it but it's no longer valid and if you look in the FAA books you will never find precision da everything else MDA it's just still something we kind of associate with it and that's why I think a lot of people get confused a decision altitude is going to be used on basically any procedure that includes both vertical guidance and lateral guidance okay whether it is officially an ICAO precision procedure or not if it's offering approved certified vertical and lateral guidance then you're generally going to have a decision altitude however if you only have approved lateral guidance then you're going to have a minimum descent altitude and so why doesn't an RN F procedure with vertical guidance like an LP V Meath precision approach requirements well the reason is because I care requires a lot of other things outside of just the fact that you have an accurate beam that can get you down to 200 feet to be considered a precision approach of which I don't know all of them off the top of my head and we will do a presentation on that in the future what ICAO needs for a precision approach but the way to think about it is it's not the glide path and the the accuracy of the localizer precision that's causing the problem it's all of the other certification requirements of a precision approach and so where does that show up when we look at our n F procedures it shows up in the alternate minimums because when you're planning to use a GPS procedure as an alternate you basically will notice that the standard or non-standard published alternate minimums are all non precision you need to use non precision alternate minimums you cannot use precision minimums our nav procedures aren't EV our and procedures fall into a special category called approaches with vertical guidance AP V and so you've got precision approaches your typical ILS you got approaches with vertical guidance which would be your LP V and your Elma VF and then you've got non-precision approaches your vo arse your low cone Lee's your LPS and your L Naville nice that's that's kind of the best way to look at it but the one thing I always tell everybody forget about the old Association precision approaches have da's everything else has an MBA that's no longer valid now if it's got approved vertical guidance it usually will use a DA and if it does not have approved vertical guidance then it's going to use an MDA okay last thing I'm going to mention on that someone's gonna go hey there's these procedures in there called plus V's right L they have plus V so does that mean I have a DA and the answer is no the plus V is not approved vertical guidance it is advisory guidance and so therefore it does not change to a DA it's it's essentially still an MDA okay looks like we got another question we have a question that I think leads in beautifully to the next slides that you're going to go through and that is this question is what should you do if you're on an LP V approach and you lose wasps on the approach or before minimums okay so this is one of the best parts about the GPS system we've got three videos that kind of step through three different scenarios okay essentially oftentimes we're talking about all we're going to lose GPS well you probably won't lose all the GPS I mean you could but maybe you'll just lose wasps you'll just you lose a component of it well your rnf system can fail down okay if you were flying an LP v and it loses the wasps satellite but it's still got rain well and if it's got bear awaiting you could do an L navi Nav if it doesn't have Barrow rating but it's just got rain at least it could still do L nav minima and so your system will fail down to the lowest love or the next level of precision that it can support if you lose everything if it no longer has RAM or if there's no L nav minima available like that procedure in Telluride then it's going to tell you to abort the procedure and you're gonna go missed approach but one of the things that people forget about when we're flying an RF procedure is the is part of our scan pattern we need to both watch the scaling to make sure that it goes in to what we used to call approach mode on an old-school GPS it would say Apr like the garments would say it in green approach mode that means that it's got rain on a wasp a system it will switch from terminal to show you your minima so for example it'll go from term to lpv or term to LP we're term 2l novena that's confirming that it meets the requirements to fly to those minima and if anything changes throughout the procedure at any time you're gonna see that change both is a message from your system so on a g1000 you know where the alerts pop up in the corner and you will often see it as a change in that scaling so LP v or LP that will switch to something else okay so we're going to take a look at an example of that we're gonna start on the we're gonna fly the RNAV again to 1/7 left right call always surprises okay so we're looking at the a procedure that we actually intro this video with the Crescent City procedure to runway 3 6 and if you're flying that procedure in a wasp based aircraft you're always gonna you know as long as it's got wash you're gonna get a LP v guidance so let's take a look at a scenario where we start with wasps service but we lose our wah signal somewhere down the line and we're gonna look at this from the standpoint of a Cirrus sr22 turbo in fact our airplane that is equipped for bear waiting so we have the capability to Barrow aid ok let's go into the video so what you can see here I'm going to just point out a couple things right now we're in route from Sitka to the Calais final approach fix we're 2.8 nautical miles out we've got a ground speed of about a hundred and four knots or a little over two minutes out a little further than that or sorry one minute out we're a little further than that and you can see that our GPS system has automatically switched to lpv guidance as we narrow in on the final approach fix so it says right now hey I've got wasps and meet the requirements for lpv we're descending down to our final approach fix altitude at 1600 and then hopefully this glide path will descend on and we'll follow that down to the runway okay so as we start flying boom right here you just see this yellow L naveen Ave this is the way our software update alerts us to the fact that we have now lost our wasp ace coverage and so right here this I should pick up in my scan pattern what this L novena haves telling me is that something has gone wrong with the RMP requirements for lpv and i should now switch to the l navi nav minima and as we continue going you're going to see that I'm going to quickly close this and come back to it so that we can yeah we're gonna get that bug off you see our logo that's the most important thing let's see I'm going to take it off from all three quickly try to be brand focused and look what happens okay we can go back to that and there's our message and if you look at the message approach downgrade approach downgraded Baro V nav use L Navi nav minima your message might be a little different and even with the g1000 or a G 1000 nxi the colors that it uses or the message that it shows different manufacturers it can all change that is not an FA mandated set of terminology it is not FM and any color your pilots guides it will often discuss what those are but some of them don't always do a great job of it but that's what we just saw to let us know that we've lost the ability to maintain that LP V version of our NP what's gone wrong we don't know it could be an internal fault with the unit it could be a loss of wha space perception it could be a lot of things all we know is the receiver can no longer guarantee that 95% accuracy at the RMP value required for an LP V approach so it's selected what it can do and in this case it said well I've got rain and I'm equipped for Barrow V Neff so I'm gonna switch to the L Navi nav minima and that's what we see and from there we'll go down okay the one thing that will also switch which we did not animate once it goes to Ln V Neve on a Garmin system you're gonna switch from a diamond to something that looks like a little sideways house they call it a pentagram and it's gonna look like this it's gonna look like a little box that goes like that it's filled in so that's a symbol that you'll see the glideslope change to okay so in that case what am I going to do as a pilot I'm just gonna look down at my L Navia have minima that's what I'm going to that's my new decision altitude that's what I'm flying to there are a couple things to keep in mind if you're flying with a glass cockpit aircraft especially g1000 we have typically queued our minima there's that little curlicue that pops up right at decision altitude that won't change that's still gonna be down at our old LP V invalid minima and so essentially in this case I just need to keep that in mind and say yeah I'm not gonna see a queue at my new da there's a second thing to consider if the procedure was to use step-down fixes and my fail down left me below some sort of effects then I would have to execute a missed approach immediately I can only downgrade and the system won't know this I is the pilot have to decide this I can only accept the downgrade if I am now above all of the minimum altitudes for the new minima line on the approach that's usually not a problem with lav Nav but it could be a problem in our next scenario you'll notice by the way in this case we lost that's not the error I want it we lost our wasps more than a minute out for the final approach fix on a garmin unit if your l novena have cable on our garmin g1000 nxi and many other garmin units if your l novena have capable and you lose wasps reception more than 60 seconds from the final approach fix it will switch or it will try to downgrade to l naveen if if you're inside of 60 seconds or past the final approach fix it will only downgrade all the way down to L nav and that's just a safety protect precaution it has nothing to do with the ability I think to generate the signal symbol what I really think is it is is it's just saying hey you don't have a lot of time to change this approach so we're gonna we're gonna keep you at a high minimum an ldap minimum if you need it for some reason to get down to L may have V nav you could execute a missed approach and fly the procedure again and load it up as a Nova don't have enough ok so let's take a look at what would happen if the GPS was to lose wasps are the same procedure except this time we are inside of the final approach fix so we are between the final approach fix and the missed approach point so right now we have full lost reception the aircraft is flying to LP v minima and I've got my diamond I'm following my glide path and my needle is centered obviously the autopilot must be on so as I go down right here you can see inside between the final approach fix in the missed approach point all of a sudden I see LP v switched to L Navin on our unit it turns yellow to alert me briefly and then all of a sudden I see a message pop up and again it's just going to show up as an alert I have to hit the button to read it it says approach downgrade approach downgraded use l nav minima and you'll notice that now matches with the L nav that I see on my HSI for scaling so now I'm gonna look down at my chart I'm gonna look at the L nav minima and I'm gonna level out at the MDA and again if the L nav minima requires a step-down fix and I find that I'm below a minimum altitude I'm going to immediately executed missed approach as long as I'm above all the minimum altitudes for the L nav minima then I can continue flying L nav in to the missed approach point and again in this case what I would probably do when I fly a DA altitude I always set my altitude select to the missed approach top altitude but in this case what I would typically do then is dial that down to my new MBA so at least I could see that MBA with an altitude select Q there okay let's look at the third scenario and this is a case where the GPS loses enough information that it can no longer guarantee any integrity essentially it doesn't have loss and it no longer has the requirements for basic GPS it can't guarantee rain either and again this could be because it's lost two satellites it could be because of Anna Seaver fault it might actually be the correct position it just can't verify anymore so again in this case we are between the final approach fix in the missed approach point we're on glide path and I'm at LP V minima and as they fly down boom okay so on our unit at times you'll see a couple things many units have the ability to do what's called a dead reckoning mode essentially they can estimate your position using the accelerometers and in this case this unit had enough information to go into dead reckoning mode so that's what this D are means now I've got in our unit a yellow CDI that's a hint to me saying hey we've gone into dead reckoning mode you're no longer following any precise guidance and the LP V is turned yellow at the same time I get a GPS loi badge that means GPS loss of integrity when you see something like GPS LOI that lets you know that essentially the receiver is not quite sure where it is anymore if even if it gives you a dead reckoning value as you continue flying that's going to get less and less and less accurate if there's strong winds or winds are changing that might not be accurate at all okay and as we continue to fly along now you're going to see a bort approach lots of GPS navigation a board approach okay so what do you do when you're flying a procedure based on our nav and your rnf system comes back to you and says I have no RF I have no idea where you are aboard the procedure well first of all you want to start climbing you're obviously going to climb at least to the top missed approach altitude but if your minimum sector or safe altitude where you're at or where you think you could end up is higher you're gonna climb to that and in my my world I'm gonna climb to the highest of either the highest minimum sector altitudes or minimum safety altitude or the missed approach altitude depending on terrain depending on obstacles depending on traffic requirements you know any of those could be the highest but I'm going to pick the highest out of those three that's what I'm climbing up to I've got a question we're going to finish this line really quick I'm if I have dr i'll use the r to navigate the procedure as best I can okay well I contact ATC and then essentially I'm gonna let ATC know right away that I have lost my ability to navigate with our nav and then I need to switch to alternate navigation and that means I'm already spinning over to things like G or a VHF nav to establish a position and I'm asking ATC right away for vectors that's the first thing I want from them again I'm a VA ting flying the airplane navigating okay I'm gonna try to you know D are my position bring up VHF bearing pointer on a vor if there's one in the area established where I am and then last communicate let ATC know what's happened and what I need the most important thing is hey guys I don't know where I'm at anymore I need vectors okay looks like we had a question okay so Mark's got a good question that goes back to the first two scenarios and what he says is if the GPS downgrades the approach but you can continue do you need to inform ATC good question you do have a loss of navigation capability which is a required report under IFR the impact to you is that you're going to fly to lower minima that's not part of your approach clearance and so what I would say is you do need to tell ATC but when you tell ATC depends on your workload okay if I'm flying down final approach and I downgrade I'm probably already over to CTF I'm not gonna say anything to ATC right now if that was to happen earlier on in the procedure and I've got the time and the ability to both first verify my new minima ensure that I'm above all the altitudes make sure that I can safely fly the approach again we're flying the airplane first aviate navigate okay yeah I got that no problem okay new minimus here okay everybody's happy we're happy then sure if I'm still in contact with ATC I'd make that call that and I'd say something simple like hey Seattle Center serves two one six Bravo Delta we've lost some level of GPS integrity we can still continue to fly the procedure be aware there may be a wass outage in the area or it could be our equipment I'm telling ATC right away something's happened I've lost possibly loss but I can still navigate this procedure no assistance is necessary if my workload is too high and I cannot make that call right now and I just need to fly the airplane that's fine what I will do is inform ATC either after I land when I close that my flight plan will let them know what happened or I'll inform them inform them on the missed approach once I have the time to communicate okay next question okay next question is this what computes the glide path in an L novena approach if you have loss on board great question essentially it's going to do exactly what it would do for an LP V it's going to use if you have wasps on board and wasps is available your system is going to use the wasp ace GPS information to compute that glide path and you know if you if you were to fly a procedure that had no LP v minima published and it was just l Navi nav and L nav and you had a space system I think all of them would use wasps first because it is the most precise and it would fly that L nav procedure still using the satellite law system for guidance it I think would only fall back to Barrow V nav if it did not have wasp because Barrow V nav is not nearly as accurate and again that's one thing to keep in mind that these procedures are these receivers are always trying to give you the best accuracy even if the minima are less you know kind of less accurate but again I can't guarantee that I can't guarantee that every receiver would go wasun barometer but that's that's what I would soon what happened okay next question Harry wants to know this what would happen at the GPS determined that the aircraft were outside of whatever scaling limits were set or integrity limits so that's exactly what you see when you when we show you that down that downgrade if the GPS system so first of all scaling and integrity are a little bit different and we kind of look at them as the same but they're not scaling is how wide your CD is okay that's essentially from center to full scale left that's your scaling so point three scaling that's that's you know from center to full scale left or full scale right would be 0.3 miles okay that's scaling integrity is different integrity is saying okay I know that I think you're here but in all reality you're not exactly there but I do know that you are within 0.3 miles of there or 40 meters of there or one mile of there that's the difference between scaling and integrity scaling is showing you where you are based off where the GPS thinks you should be okay and integrity is the GPS saying excuse me saying I think you're right here but I really know that's probably not right you're just somewhere in this big zone if the GPS realized that you're outside of its integrity limits if it realized that its integrity estimations weren't right then you would end up with a downgrade and a mess if you deviate far enough off the scale that the scale goes full-scale the GPS is just going to show you typically crosstrack error and it's leaving up to you is the pilot to fix it and of course if we end up there we should be flying a missed approach procedure but that's something to think about again and it's really can get confusing scaling is just how far left and right the CD is integrity is the system saying okay I think you're here but I know that's not really your position your position is this kind of big area and it's you're within 40 meters of where I think you are okay next question next question is this is Barrow aiding the primary reason why so many plates have temperature restrictions for the L novena procedures due to the true altitude above the ground okay that is another fantastic question these are great questions so there that's part of the reason you can find ten temperature restrictions on non Barrow weighted procedures okay and that's simply because when they estimate your sea-level pressure essentially your altimeter will read accurately on the ground at that Airport okay so when you get that altimeter setting and you set that in what that means is at the moment it was taken and computed sitting at the airport reference point or at this at the sensor site or somewhere there your altimeter would read accurate field elevation okay as you start to climb those pressure levels aren't at that standard one inch per thousand feet in cold weather they're much closer in warm weather they're much farther apart the problem is with the closer further apart means you're high hey you may not make it out of the clouds but you're not gonna hit anything okay so if the temperature is much warmer than standard you're not really as low as you think you are you're actually a lot higher but when it's really cold those pressure levels kind of condense and so now you're much lower than the altimeter says you are and so that right there causes that cold temperature problem that's magnified when we start to use Baro V nav because now not only are we using the not only we're using the altimeter system tell you your da or MDA at the bottom but we're also using it to try to draw a glide path and that glide path isn't going to be completely right because of the cold temperature so yes uncompensated Baro V nav systems will oftentimes have temperature limitations on them however most modern Baro V Neff systems can compensate for non-standard temperatures and so you'll actually type in the system what that temperature is at the airport and it will use that to redraw your glide path all that being said even with compensated Bhairavi Neve or lost based guidance so L P V or L Navi Neve if the temperature is cold enough and there's an obstacle that's just at the right height you could still end up with the temperature limitation and in an MDA or da adjustment even if it's not Beryl V Nev okay next question next up Serge wants to know this how do you know if you have a GPS with Baro ating that is a great another great question I'm going to stop to say Nevin Serge you asked questions why which I really appreciate it I like hearing the same names hopefully it means that people are really enjoying these the easiest place to look is going to be in your pilots operating handbook or your airplane flight manual or the supplement that was issued with the GPS that's installed in your manual so that paperwork is really really important don't look at the paperwork you download online okay so you'll find a lot of flight schools will post a g1000 manual online like hey everybody use this a study that is different than the manual in your airplane flight manual and that's because the same equipment can be certified for different things on different installations not every aircraft will have the same capabilities even though it may have a g1000 in the front these systems are incredibly versatile I mean you could have them equipped with DME and Bhairavi NAMM and all these different things or you couldn't so let me see if I can find that really quick I'm gonna open up for flight because that's where I keep my aircraft P a copy of the Poh and again this is not the actual flight manual but it's a it match in this case it matches our flight manual so I'm gonna go forward and I'm gonna look at limitations and I believe it's going to be in systems and equipment limits here and just give me a second that's gonna take me a second to find it so in this section right here you can see what you're allowed to fly so this is very this is kind of where you're finding that answer so in paragraph G the perspective integrated yannick system is compliant with a c9 hunt 90-100 a and so it is eligible fly RFQ or tear outs or nav Sid star so DPS and eligible to use our nav substitution or alna rnf as an alternate means of navigation so that's what tells us that we can use our nav and then if we keep going down here it says that we can use s pass or GPS for IFR out terminal and proach and this is the Barrow vina have I believe no I think it says it differently now it's M so L says that we can fly L Navi nev and l pv m says barometric vertical vet navigation barrow via have operations may be conducted if s bass is unavailable or disabled and then it'll say the perspective in avionics system will provide automatic temperature compensated glide path vertical guidance and has been shown to meet the accuracy requirements of VFR IFR enroute terminal and approach barrow vena have operations within the contaminants us in alaska in accordance with AC 21:38 d so this is a great question and you notice just a lot of paragraphs there and there's a lot of requirements because the RNAV and gps requirements are huge there's a billion things that you can do with them and they all have different levels of certification digging through the aircraft's airplane flight manual and reading that limitations or the limitations in the supplement that's where you'll find out if your aircraft is barrow vina have equipped one last caveat a lot of flight schools have a mix of different airplanes they all might be g1000 Cessna 172s but they're different yours they were bought from different people they didn't all come in the same order and so they're not all the exact same just because one of those installations is approved for barrow DB nav doesn't mean the other one is and so be careful when you're flying in a fleet of mixed airplanes that you don't just make an assumption hey all these must be approved because I saw in the Poh that one is and they all look the same keep in mind that equipment and certification requirements can change between serial numbers and you know you really if you're flying different aircraft either your flight school needs to say yep nope they're all certified here's the master afm that represents the entire fleet or you need to be checking each one of those aircraft to determine your requirements okay last thing i'll say there if the aircraft isn't certified for barrow v nev the our nav system should not offer it to you that's the concept so one other way you would know it's not capable of air out barrow v nav is if you lose wasps it's not going to even give you an elm Avena option it's just gonna drop straight down to L nav okay next question okay we got time for one last question here and then we've got others that we're gonna answer in the chat so for buddy hangs on we'll try to get though to those as quickly as we can the question is this our planned GPS outages always 100% out with no service or there different levels of outages that's a really good question we've actually talked to the FAA about this there's there's different no times for different things and keep in mind that just because it's noted out of service doesn't necessarily mean that it will be out of service 100% of the time but if it is noted out of service then you need to treat it as if it could be and have alternate navigation options so if WAAS is no time to be unavailable in an airport like an alternate Airport then you would need to use the basic GPS rules when planning for an alternate there if you get there and you actually have loss it is available you can start the loss procedure just be aware that it may go away at some point in time and so that's that's something to think about if if you know just because it's no timed doesn't mean it will be gone but then for planning purposes if it is if s Pass is no time to be out of service you need to plan the flight as if you were not s pass equipped while you're actually flying sure if you got the signal you can use it but the flight needs to be planned and the routes that you accept need to be flown with the fact that yeah I can fail back to VHF if this happens to go away or basic GPS if it happens to go away okay it's Colin said we have some more questions in the in the chat so we're going to try to get those through with comments also I know we cannot cover all things lpvr now have GPS in one sitting I think everybody would go crazy so we'll do more of these let us know both in the comment section on this video also send us emails to let us know what more you would like to hear about on this topic what examples you'd like to see that'll help us out we'll get more of this out in the future a couple other quick items ah SH Kosh is coming up in a couple weeks bold method will be at Oshkosh will be teaching Monday Tuesday and Wednesday at 12:45 p.m. at the EAA pilot proficiency Center each of those days there's some VF and I if our presentations there they're fantastic presentations we really like to meet you in person so if we're going to ash Kosh I would love to have you at those presentations that the pilot prefers the proficiency Center that's a mouthful and they're 100% free so all you got to do is show up and then we'll be walking around we don't have a booth but we were walking around and we got working with different vendors and so if you see us please stop by and say hi and otherwise if you like to learn something from this video tonight please let us know in the comments and give us a thumbs up we really appreciate it and it helps increase our search rank thanks again tonight and we hope to see you at Oshkosh or online in a couple weeks good night [Music] [Applause] [Applause] [Applause] [Applause] [Music] [Music] [Music] [Applause] [Applause] [Applause] you

Channel: Boldmethod

Views: 131,158

Rating: 4.9236035 out of 5

Keywords: lpv approach, gps approach, lnav approach, lnav vnav approach

Id: O5q71bECrT4

Length: 89min 32sec (5372 seconds)

Published: Tue Jul 09 2019

Reddit Comments

[u/organman91]

Yes it is over an hour long but this really helps me understand what all those letters in GPS approaches mean.

This channel has been putting out some excellent livestreams for a few months now.

[u/Hemilit]

So awesome explaining. Thanks for sharing.

[u/[deleted]]

Can we get an ELI5 in under 5 minutes please