Instrument Approaches - An Introduction

an instrument approach allows us to fly through clouds or it Allah allows us to fly on days when visibility is very low and an approach is designed to get you out of those clouds or close enough to the runway that you can see it even in times of very low visibility we're going to talk about instrument approaches by analyzing one instrument approach in particular the RNAV GPS runway two-seven approach at Lakeland now the approach is divided up into two parts first of all we have to get lined up with the long runway and the second part is we have to get low enough so that we'll be able to see the runway assuming the clouds are very low so this approach played all approach plates are divided up into two segments the plan view and the profile view the plan view house tells us how to get lined up laterally with the extended runway centreline and then the profile view shows us when we can descend when it's safe to go low to get in a position that puts us right in front of the runway and ready to land now these approaches are very long they'll get you lined up on sometimes a 10 mile final for the runway you can see that there are little fixes listed here on the approach along the final approach course we see guildy decayed and covenant using any IFR GPS or a site like sky vector or for flight so let's take a look at the approach path that we're getting lined up on as we approach runway two-seven so here we have Lakeland Airport and I can type in the fixes guilty ich Aid and cover and then the airport and you'll see that these fixes make up a very long straight in 10 mile final for that runway you can see here is skill D here's E Kate and here's coven uh so this will give us plenty of time to get lined up and stable as we descend toward the runway so let's analyze the plan view a little more closely again it's just a way to get lined up on a long straight and final you'll see that in the plan view they have the black line that represents the final approach course and then they have a little icon that represents the airport you can see the two runways at Lakeland right here and you can see that we are going to get lined up to land on runway two-seven so once we're on that line and that's going to be shown on our GPS since it's a GPS approach once we're on that line then how do we know when it's appropriate to descend that's what the profile view is for so here's the same fixes guilty eek Aid Covina and the airport the airport in this case is looked at from the side so this is the runway the same as we saw on the plan view and it's telling us that when we are outside of guilty if we've not yet reached guilty we should be at 2700 feet then once we're past guilty and in this section between guilty and eek Aid we should be no lower than 1700 then once past eek aid but before Kovner we could be as low as 780 feet and then there's one final altitude that's called our minimums and it depends on the type of approach being flown that final altitude and we'll get to that more later so I mentioned there's different ways to fly these approaches and the minimums will change depending on which one you choose the first is called a precision approach now a precision approach is a way to descend slowly and steadily all the way down to the runway you could start descending at guilty and descend all the way down until what are called the approaches and minimums at which point you must either land or you must go missed there are needles that we can use to track this to see if we are above or below this glide path now there's more than one way to fly a precision approach and the only requirement is that we have to be following the glide path we have to be following this nice steady descent by what's called the final approach fix so if we so chose we could fly at 2700 until guilty and then choose not to follow the glide path but descend rather quickly to 1700 but then we must at the final approach fix eek aid beyond this nice steady descent all the way down to minimums and that would count as a precision approach now there's another way to fly most any approach and that is a non-precision so this is the same approach you'll see that we have the same fixes gil de que Covina and the airport however this time instead of descending in a steady fashion following a glide slope we're going to descend by what are called step downs so after we cross each fix will be at 2700 out here then after we cross this fix we can initiate a relatively rapid descent to the next altitude and just hold that because that's the lowest we can be in that section then after eke 8 we can descend again rather quickly to 780 and then after Kona we can descend to our non-precision approach minimums and just hold those until we can either see the runway or we have to go missed but how do you track these courses how do you stay on these lines well we have what are called either a vor receiver or an ILS receiver and it will let you know whether you're on the line or not we're going to talk about the precision approach version first so if you think a precision approach or any kind of approach you have two things you're worried about you're worried about your altitudes and you're worried about your heading so or the course that you're tracking inbound so first of all we need to know are we on this line and there's a needle that will tell us that and then the next thing we need to know is are we on the appropriate descent path are we descending too quickly or are we not descending quickly enough so the two needles on the ILS receiver represent each of these components the needle that goes up and down and moves left to right will tell us if we are on our lateral approach path it'll tell us if we're on that final approach course or not so if we drift off of it the needle will show that we have moved if we drift off of it to the right the final approach course will be to our left and the needle always represents where that final approach course is for example in the second image the needle that goes up and down has moved to the right now we are always represented by the middle of the instrument but the needle is to the right so it's telling us that our course where we should be is to the right so if we look back at our plan view the course where we need to be as to our right so we are somewhere over here to the left and we need to go right in order to get back to our final approach course now the other needle is the glideslope needle the glideslope immediate needle run is the left and right one but it moves up and down and again we are represented by the middle dot and it's telling us where we should be it's telling us where that glide slope is in this case the glide slope is below us so we are too high and we need to descend which will make that needle move back to the middle and will be again back on that nice vertical path descending to the runway so for example if we're descending from ek to the runway and we end up too high up here somewhere the glide slope needle will go down showing that where we should be is lower or if we go too low after ek the needle will move up showing that the path we're supposed to be on is above us but what if we're flying a non-precision approach well we only need one needle in this case because we're going to be able to identify when we've passed each of these fixes and we know the altitudes that we need to be at when we're past those fixes the rate of descent is not so important we just need to maintain above those minimum altitudes so on a non-precision approach you need only a localizer you need only one needle so in this instance the glide slope is not functioning or possibly not installed in this aircraft and we have just one needle that moves left and right so this first instance we are on the path same as with the ILS in the second instance the path we should be on is to our right so we need to correct our course to the right to get back on it now we have no vertical information from this we're going to get the vertical information by knowing at what point we are on the approach and whether we are past each of the appropriate fixes and if we're past them then we know the altitude that we can be at according to the profile view so there are several types of approaches in both non precision and precision and when you look at an approach plate you just have to know which ones are precision and which ones are non precision in order to know how to fly them here's several examples of non-precision approaches that you can find on approach plates and several examples of precision approaches you can find on approach plates so let's go look at our approach plate and let's see which options it offers so for this approach we can see the minimums box down here and it's telling us the types of minimums that it offers the types of approaches you can fly using this single approach plate and it's telling us it offers an LP V approach and an L nav approach LP V we didn't have to know is a precision approach it would involve flying down this slope steadily an L nav we have to know is just a non-precision approach it involves it going to the fix and then descending at our own rate down to the minimum sections the minimum altitude for that section let's look at another approach this is the ILS approach we can look at its minimums box and we can see that this offers two types of minimums it offers an ILS which we have to know is a precision approach and a localizer which we have to know is a non-precision approach and notice the final altitudes which we'll get into more later are different depending upon the way the approach is flown so let's break this approach down a little bit more let's start with lateral navigation we need to know how to get to that final approach course there's several ways to start the approach it depends on your preference or what you work out with ATC but first of all you can start an approach always from what's called an initial approach fix so there are three initial approach fixes on this approach there's one called conde one called remy and one called gil d so you can pair identified by the letters I AF and it means that you can proceed directly to that point and then proceeded to fly the approach so for example if we were out here to the north we could fly to Conde then we could fly straight south until we get to Gil D then we could fly straight west until we are on our final approach course you could also start from ret me if you were somewhere to the south or you can start from Gil D now if you start from GUILTY it's a special type of initial approach fix you'll see that it's fairly plain what you do if you start from Conde you go you go south and then you turn right and intercept the final approach course but what is this circular pattern here at guildy well if you choose to start at guilty which you can no matter where you are it's perfectly legal you can request it you would have to somehow get turned around and lined up with this final approach course so take the example that you are perhaps somewhere out here to the west and you request the approach from guilty you're gonna have to fly to this fix to get started and then you're gonna have to come up with a way to turn around on a spot and get lined up with the final approach course because you're going the wrong way so that's what they've given you they've given you a way to get turned around and what they're going to do is they're going to use what you already know about holding patterns to fly to guilty and then get turned around using one of the standard holding pattern entries now this is not a holding pattern per se it's called actually a hold in lieu of a procedure turn and it's a special special feature of approaches so let's talk about the different ways that you could fly to Gil D and get turned around to fly the approach so from a couple of different locations we can start this for example start with our example that we were over here somewhere to the west and we want to proceed to guilty so we're gonna fly straight to guilty first of all now from your knowledge of holding patterns you can see that if this were a hold the appropriate way to enter it would be a teardrop so we would fly to guilty and we would fly a course it's 30 degrees offset from the unbound course and then we would turn around and then track the final approach course inbound now what if we were somewhere else what if we were up here to start well in this case again we would start by flying to guilty and you can see from you from your knowledge of holding patterns that this would be a parallel entry so we would track the inbound course backwards turnaround back to guilty and then we would be on the final approach course inbound but what if we are out here somewhere to the east it doesn't seem to make a whole lot of sense to fly to Guild II and then fly around the hold it would just be a waste of time before we go in bound while they've realized that on this approach and what they've given us they've given us a special note that authorizes us to not have to fly once around the hold it's called no PT so for example if we're starting this approach from condi this is the first time you'll see this no PT so this is just reiterating the fact that they do not want us to fly around this hold if we are starting the approach from condi it doesn't make sense it's a simple right turn and we can go in bound so similarly if we're approaching guilty from anywhere between these two radials or between these two headings if we're coming anywhere in this section which would be anywhere from here all the way to here so we could be coming from this direction this direction or this direction in which case it would not be appropriate to fly around this track because it says no PT now be careful with this because if there is a hold in lieu of a procedure turn depicted it is typically mandatory to fly it unless you have some kind of a special note authorizing otherwise now if there's any doubt if it seems like it's just going to be a waste of time simply clarify with ATC and they can waive that requirement now let's talk for a minute about starting the approach at condi and what altitudes would be appropriate to fly now I mentioned that the profile view is the one you look at to see altitudes so but if we look at the profile view we can see that it doesn't have every fix condi is not listed it only lists the fixes that are along the final approach path starting with guilty so what altitude would be appropriate then if we're flying from condi to guilty well since this part of the approach is an initial approach segment and it's not lined up with the final approach course they're going to print the altitudes right on the plan view so it's telling us that from conde to guildy the appropriate altitude is no lower than 2700 feet and the same applies to rent me then once we're on the final approach course they give us another little hint here just as a bonus but we would refer to the profile view to see altitudes along the final approach course but what about starting from guilty what altitudes are appropriate it is not listed here in this view so we will again look back to the profile view because this is somewhat aligned with the final approach course they actually have given us that information in the profile view so let's go take a look at it again you can see in the profile view there's a little bit of extra information you might not have noticed it's up here in the upper right and it tells us that during the holding pattern during this hold and blue of a procedure turn you are considered to be in this segment of the approach and they're going to give us an altitude that's appropriate to be at so if you are flying around this hold in lieu of a procedure turn the minimum altitude you can be at is 2700 now this can get confusing sometimes because you think that once you cross guildy you can be at 1,700 feet which is normally true if you are approaching from the east however if you're approaching over here from the West and you are not yet on the inbound side of guildy you need to refer to the part of the profile view that is outside of guildy at 2700 feet so if we're flying to guildy and we're going to do a procedure turn the lowest altitude we can be at again 2700 feet then once you cross guildy inbound then the lowest altitude you can be at is 1700 feet now there's another part of this approach that's very important after you pass through the intermediate and the initial approach segments you'll find yourself on the final approach segment now this final approach segment is always indicated by the presence of a final approach fix that's what the FA F stands for here and I've already mentioned that the final approach fix is special and that if you're flying a precision approach the final approach fix is the point at which you must be on the glide slope you're not allowed to do step downs anymore if you're going to fly this as a precision approach now it's important for other reasons but we need to be able to learn to identify this final approach fix now it's identified in both the plan view and the profile view on the plan view it's identified by the letters F a F above a certain fix and on the profile view it's identified by this Maltese Cross if you're flying it is non precision and it's identified by this lightning bolt if you're flying it as precision now on this approach both final approach fixes happen to be in the same spot but that's not always the case so you have to learn to identify the final approach fix depending upon how you are choosing to fly the approach so we've already mentioned that there's three ways to start this approach depending on your choice you can either start it at conde you can start at at guildy or you can start it at ret me however there's a fourth way to fly this approach and most every other approach and that is with the assistance of radar vectors from ATC now this is often the fastest way to fly an approach because what it does is ATC will assist you to get on the final approach course somewhere on the intermediate approach segment and this is again another reason why that final approach fix is important if ATC is going to help you get on this final approach course they must put you on the final approach course before the final approach fix and you're going to have to fly from the final approach fix to the airport using your own instruments and navigation so how does it work well ATC will give you headings to fly and altitudes to maintain until you are safely established on that final approach course so for example they will give you vectors headings to fly that will gradually get you lined up to a point where you are aimed at the final approach course then they will give you the final instruction fly a certain heading maintain a certain altitude until established what do they mean by established well we're going to get into it in more detail but being established simply means that you are on this final approach course and you are a to track it inbound so you're gonna hold an altitude and a heading and remember how do we know when we're on this final approach course it goes back to our localizer Needle as we approach the final approach course you'll see that the needle will move from all the way off to one side until it starts to center and once it starts to Center you can start your turn to that final approach heading and then keep the needle centered as you fly along the final approach course so again at this point you're flying headings and altitudes as assigned by ATC so when then is it appropriate to break those to break the heading that they gave you and to descend below the altitude that they gave you well it becomes important that you are established on the approach now established on the approach has a specific definition and that is that you are within one half scale deflection of the localizer needle so if in this example to the left the localizer needle is all the way off to one side you are not very close to that line and thus you might be in risk of hitting an obstacle or something if you descend because they've not cleared that part of the earth to be descending to the altitudes that are published on the approach plate however once you get within this half scale deflection then they've guaranteed that you are in a safe position to start following the altitudes as listed on the approach plate so in our example here as we fly heading two-five-zero and maintain 2,000 we'll continue that until we see our needle start to move from one side towards the middle and once it gets halfway to the middle we know that we're close enough to this line that it's appropriate to descend on our own which in this case would be to the altitude published on the approach for this segment which is found in both the plane view and the profile view which is 1700 feet so then we would turn to intercept the final approach course inbound and we would maintain 1,700 feet until we reach ekd at which point it would depend on the type of approach we're flying whether we fly the glide slope down or whether we do step downs to our final altitude so what are these final altitudes well we already know altitudes now to fly when you're on the initial Prout segment the intermediate approach segment and we even know an altitude to fly if we're flying in as non-precision that's past the final approach fix we know that we can make a step down to 780 feet in this section but what about this last altitude it's not printed here in the plan view or the profile view well like I mentioned it depends on the type of approach being flown and the information is found in what is called the minimums box we mentioned that there are precision and non-precision approaches listed here the LP V is a precision approach and the minimum final altitude the lowest altitude that you can descend following that glide slope down is 342 feet now if you're flying it as a non-precision approach you will descend to 780 feet after ich Aid and then after you pass Covina you'll need that final altitude and you're going to look for that in the minimums box under El nav for the non precision version and you know that the final altitude the lowest you can design when flying this as non precision is 520 feet but what about these boxes on here we see that some of them are divided up depending on category so for the LP V in the L nav the minimums are the same regardless of category but if you're flying this as a circling approach which is beyond the scope of this video then the minimums will be different depending on your category and some approaches even the precision and non precision are divided up by category so it's important to know what category aircraft you are flying aircraft categories are based on the aircraft's publish approach speed or 1.3 times VSO which is the stalling speed in landing configuration so most of the aircraft the smaller craft that we fly do not have published approach speeds so we need to calculate what is 1.3 times the stalling speed and landing configuration and then if that speed falls within these range values we can determine the category that our aircraft falls under so for example our system 172 stalls at about 40 knots with all the flaps down we multiply that by 1.3 and we get 52 knots and we can see that speed less than 91 knots our category a so our aircraft is a category a aircraft so let's jump back really quick and we're going to complete our examples of flying a precision approach and a non-precision approach as far as altitudes are concerned if you're flying this as a precision approach you must be on the glide path at EK the final approach fix and then you must follow both needles down to the minimums we never specified what this minimum altitude is but now we know if we go and look at the approach plate we're flying this as a precision approach that final altitude will be 342 feet and we can go no lower than that until unless we have visual contact with the runway if we're flying this as a non-precision approach we know we're going to step down to 780 feet after ich aid and then we're going to quickly drop to our final altitude again not depicted here well we need to look that up in the minimums box and now we know that if we're flying this as an L nav non-precision approach our final altitude that we can drop down to is 520 feet now that altitude then should be held until you reach the missed approach point so what is this thing called the missed approach point well every approaches goal in real life is to end with a landing however there's always the possibility that the weather got worse and you are unable to see the runway even though you're at your lowest permissible altitude now in this case it is not safe to continue to descend you must be visual at that point for the regulations so what they've given us is they've given us a way to safely climb back away from the airport and try again or go someplace else so at this point you are low and you are close to the airport so you can't just go wherever you want because there could be mountains obstacles in the way so they've given us a prescribed route that will allow us to climb safely back up away from the airport back to some kind of a safe and route altitude the first thing we need to know though is at what point are we required to go missed if we don't see the runway at what point must we abandon the approach start climbing and go find something else to do well that point is called the Mist point and it's depicted in the profile view you'll see that it's depicted differently depending on if you're flying this as a non-precision or a precision the missed approach point is typically the point at which a solid line turns into dashes however since this approach accommodates both non precision and precision they're only able to show the point where the precision approach turns into a mist so the point at which the solid black line turns into a dashed line is the mist approach for a precision approach if you've flown down the glide slope to minimums which is the altitude that's represented by the height of this black line above the runway and you're unable to see the runway or the runway environment then you must immediately begin a climb and then follow what are called the missed approach instructions now the missed approach point though is different for the non-precision approach and it's not totally clear by looking at the profile view here if you are flying this as a non-precision approach the rule is that the missed approach point is the last depicted Waypoint so we see we have our way points here our fixes Gil de Kade covenant is the last depicted Waypoint in this case it is our w tu7 so the missed approach point for a non-precision approach is going to be what's in the GPS labeled as our w tu7 which happens to correspond with the exact end of the runway so the missed approach point for a non-precision approach is a fix and it's the last one the missed approach point for a precision approach is going to be indicated by nothing other than the altitude at which you find yourself so if you're both on the glide slope your aunt you're at the correct spot vertically and you find yourself at 342 feet you are required to abandon the approach to go missed and try again what do you do now well they give you missed approach instructions on every approach plate they listed in four different places on each plate they list it in text form in the upper right they list a drawing on the plan view so they kind of show you generally where you're going to be going so we can see from the plan view that it's going to be some kind of a turn to the north when they give you icons down here in the profile view that graphically depict what you're supposed to do in this case you're supposed to climb ahead to a thousand then make a climbing right turn to two thousand and go to the intersection plumie and finally they give you a little bit of information in the profile view but again they're only showing you the missed approach point here for the precision approach by the dashed lines but they're indicating that once you get to that certain altitude at that time you should go missed so you can see now that there are multiple ways to fly even a single approach based on a single approach plate so when you're in the air and you're about to start this you need to make decisions as far as how you're going to fly this approach where you're going to start it whether you're going to fly it as a precision or a non-precision approach and then of course remind yourself what to do in the event that you cannot see the runway so we're going to end with one example of a way to fly this approach all the way from start to finish and this is what's called briefing the approach so we're flying the GPS runway two-seven approach to Lakeland where make sure that we have the right approach plate in the right Airport we are somewhere up here to the north so we think it would be most appropriate to start this approach from conde so we're going to make that request with ATC then if approved we're going to fly to condi and whatever end route altitude we happen to be at perhaps it's 3,000 feet then once we're at condi we're going to fly about a hundred and eighty four degree heading whatever it takes to stay on this course and if we are cleared for the approach we're going to be able to descend to 2700 feet at that time then we're going to make our way to guildy then after guildy we're going to make a right turn to about 274 degrees to stay on this course line and we know that immediately after crossing guilty it's going to be okay to descend to 1,700 feet we're going to proceed then to eek aid and we need to know at this point if we're flying this approach as a precision or a non-precision approach in this case I'm going to make the call that we're flying this as a precision approach so we're going to continue to fly to eek aid at which point we must intercept the glideslope so both needles should be alive at this point and when we're at ek do needles should be approximately in the middle at which point we're going to start a descent now this altitude right here doesn't apply to us because we're flying this as a precision approach but we're gonna then start our nice steady descent following the needles all the way down to minimums and the minimums for the way we are flying this approach are 342 feet so if we reach 342 feet while following the glide slope and we are unable to see the runway we're going to brief our mist approach we will immediately start a climb straight ahead to a thousand feet then we will make a climbing right turn to two thousand feet and we'll hold two thousand feet while we navigate ourselves direct to plumie then once we get to plumie what do we do well we're going to look up here again and we're gonna see that after we've gone mist we've made that straight ahead climb to a thousand and then a climbing right turn to two thousand we're going to go to plumie and we're going to hold these dashed lines indicate that this is a holding fix associated with the mist approach and then we'll hold until we get further instructions from ATC or until we figure out what we're going to do next so at this point we've analyzed only one approach at Lakeland but you have enough information to decipher a lot of other approaches so try your hand at pulling out various approaches at your favorite airport and look for the commonalities between them there's always going to be some kind of a final approach course depicted in black there's going to be some kind of a way to get to it whether it's a hold and lieu of procedure turn or another GPS approach and you'll have these initial approach segments that you can fly you're always going to have a profile view and a plan view the plan view that shows you laterally how to get lined up with the runway and then a profile view that shows you appropriate altitudes to be at as you fly the approach also look at approach minimums and try to decipher which ones are precision and which ones are non precision and talk yourself through how you would proceed to fly each of them finally look at the missed approach determine the missed approach point for both the precision version and the non-precision version then read the missed approach instructions to yourself and see if you can decipher what they would like you to do in the event that you're unable to see the runway angle missed

Channel: alexaviation

Views: 94,073

Rating: 4.9601989 out of 5

Keywords: ifr, instrument approaches, iap, iaf, faf, minimums, missed approach, precision, nonprecision, approach

Id: 7qbaDWQjlZk

Length: 33min 30sec (2010 seconds)

Published: Thu Oct 27 2016