How To Use MDA, DA, And The Missed Approach Point: 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 going to talk about M da da and visual descent points how to use each one of the three these are something that kind of confused both instruments students and instrument pilots alike and well on the face they seem fairly simple there are some key differences that really affect the way we fly and considering when you're at MDA or da you're essentially as close to an obstacle as you possibly will ever get well still remaining protected it really is important to understand the nuances of each so that's what we're going to go through tonight we've got Corey chrome Eric on chat and as you have questions send them out to him he'll forward them over to Colin Cutler who's our technical director and then he'll bring them online in the presentation we have lots of time for questions tonight so if I lose you anywhere or if you want me to go into more detail jump in right away don't wait till the end of the presentation okay so we'll start with a quick overview of MDA then we'll talk a little bit about visual descent points and continuous to cents on final approaches we'll talk about what happens if we go missed then we'll move into decision altitude and we'll also cover what you need to see to be able to go below either da or MDA but let's start with the basics and that really is the definition of minimum descent altitude so MDA also known as minimum descent altitude it's the lowest altitude expressed in feet above mean sea level to which a descent is authorized on final approach or during a circle land maneuver and execute an execution of a standard instrument approach procedure where no electronic glide slope is provided that's right out of the aim to simplify that a little bit essentially we look at that is the minimum altitude that you can descend to we typically say on a non-precision approach not an approach with vertical guidance not a precision approach but we typically say a non-precision approach one of the things that I really like to clarify if you've got a plus V GPS equipped aircraft so let's say you're flying a G 1000 with wasps or a different Garmin unit with wasps or and a Verdine with wasps oftentimes as you load a procedure you'll see the option to fly a plus fee and your GPS will provide what we call plus v or advisory vertical guidance it's not a certified glide path and so you're still essentially using an MBA a minimum descent altitude okay let's compare that to a DA or a decision altitude a decision altitude is a specified altitude or height in the in the precision approach a twist at which a missed approach must be initiated if the required visual reference to continue the approach has not been established okay and that is one of the big things that separates an MBA and a DA an MDA is just an altitude limit it has nothing to do with action you have to level out there until you meet requirements to send below but you can continue flying along at MDA until you reach your mister proach decision altitude is both an altitude limit in sorts but at the same time it is your missed approach point so when you're flying either an a PV approach with vertical approach with vertical guidance or you're flying a precision approach down to the point where you have a DA your missed approach point is your da it's no longer the missed approach point that's published on the chart so people get very confused about that they said well there's a separate map published on the chart that's true that's for a non-precision approach your missed approach point when you have a da is your decision altitude okay so with all of that what is a visual descent point so a visual descent point or a VDP is a defined point on the final approach course of a non-precision straight and approach procedure from which a normal descent from the MDA to the runway touchdown point may be commenced providing that the approach threshold of that runway or the lights or the other markings identifiable with the approach end of the runway are clearly visible to the pilot so that really brings up ok so what is we'll get into V DPS in just a little bit more of a second but what do you need to do or to have to go below da or MDA well there's three things number one you need to have continuous position to land on the intent or continuous position to land on the intended runway so essentially what we're saying is that you should be able to make a normal and continuous descent down to land on the runway what is normal that's up to you three degrees sure good it'd be four and a half absolutely could it be six if you feel that that's normal the FAA essentially allows the pilot to determine when a descent is normal and this is something that you really need to know both your skills and your aircraft's capabilities we'll talk about this in a second but on minimum descent altitude you could fly so far towards the missed approach point and close to the runway threshold that getting from the minimum descent altitude down to the runway may not be very practical and if you try you could put yourself in a very awkward place and we'll talk about that more in a little bit of a second but essentially you need to be in a normal and continuous position to descend and land on the runway okay number two what you need is required flight visibility this one is really important because we include the word flight there was a time where that really wasn't included it left us a little more ambiguous but now we clearly say flight visibility and so that means under part 91 okay when we're flying out of part 91 and a cat one approach we don't need in our VR reading we don't need prevailing visibility reading too and what we need to do is use our eyes and determine how far we can see and there's times that you can trust our VR and prevailing visibility and there's times you can't I've flown approaches in the northwest where our VR says there's less than a quarter mile of fog or prevailing visibility says that and the runway is completely clear because the fog bank is sitting 12 feet off to the side right on top of the measuring equipment I've flown other cases where they're reporting two miles visibility but I can't see anything other than maybe a light on the runway but I clearly can't see further down it and so in that case I don't have the visibility to land even though the reporting systems say that it's there and so that's one of the things we tell people category or part 91 you are essentially you need to rely on your eyes there's a couple different tricks you can use you can look at the runway length you know the runway itself it's 6,000 feet is about a mile you can jugg your distance from the runway these are all good ways to determine flight visibility but you need to have your minimums in flight visibility not in reported visibility okay and the third item on there is that you need to have the runway environment in sight and there are ten things that the FAA calls the runway environment here's the first I think we're coming into was this San Luis Obispo calling okay so San Luis Obispo and we could see that right there that little white cross you can see that is a bigger house ranked it down a little bit yeah you can see this little white cross right here that is the medium intensity approach lighting system Mouser and it's got alignment lights okay so there are a runway alignment indicator lights or the rabbit this is just a steady picture but you can see that bright strobe flashing that leads me in you'll notice that's really all I can see if you really study the picture maybe you can kind of see a threshold but I wouldn't say clearly but I can clearly see the white approach lights that allows me to go down to 100 feet above the touchdown zone elevation and if you're an instrument student this is one thing I always tell you to be careful about when you say it because we often think about this when we're looking at a precision approach chan ILS and an ILS typically takes us down to around 200 feet above the ground so people say well you can go down another 100 feet on an ILS if you see the white approach lights that's true if the ILS stops at 200 feet but it's really not you can go down an extra hundred feet it's that you can go all the way down to a hundred feet above touchdown zone elevation and it's not just on a precision approach it's on any approach you can get down to a hundred feet above touchdown zone elevation if you see the white approach lights ok so what's it take to get you all the way down to land well in the approach lighting system one of them is the red side row bars you see them here these are typically you're going to find these more an else--if one in two systems you're typically not found at small airports so air carrier airports typically with category two or three approaches the red terminating bars so these n bars here if you see red approach lights that means you can continue down to land your other items are the threshold the white beginning of the runway the threshold markings themselves you can see essentially those those bars that you see right before the numbers and the green threshold lights those would count to get you all the way down to the ground the runway end identifier lights are a ILS those are those flashing strobe lights that you see off to the sides of the runway this is something you want to be a little bit careful about because runway end identifier lights rails sound like runway alignment indicator lights are a ILS are a ILS is the rabbit that leads you in that strobe that sequences you in you can get down to a hundred feet above touchdown zone elevation our ILS rails the little flashing lights at the end of the runway those will get you all the way down to the pavement and then the other thing you want to watch for is you need to know the approach lighting system at the airport because you could mistake possibly re ILS for Oh Dalls the omnidirectional flashing lights and if you don't see anything other than the Odle lights which are flashing that won't get you all the way down o Dalls aren't in appendant runway lighting system so when you're flying approach this is why we always brief the approach lighting system so we know what we're looking for and so when we see it we know if that allows us to go down to a hundred feet above touchdown or all the way down to the runway okay what else could you see you can see the visual glide slope indicator here we've shown of a Z but it could be a Pappy or any other certified glide slope indicator on the side of the runway the touchdown zone or the touchdown zone markings so those are those markings that you see stretching down to the aiming point markings and then that touchdown zone lights which are basically thick bars of Lights that run from the threshold down the runway then we have the runway itself or the runways markings so any of the paint on the runway whether it's the numbers the aiming point markings or the stripes as long as those are clearly visible and then finally the runway lights itself and so the runway lights you know we're really talking about the the edge lights on the runway but it could be you know of course also the green threshold light that starts the runway you'll notice here that things like wind socks or taxiway lights those don't count and that's because that's not part of the runway environment itself you may see the airport environment but you need to see the runway environment to descend below MDA and land and so that's that's an important distinction and it's really important again as I said to know what you're looking for before you're looking for it it makes it easier to understand if specially with an approach lighting system if you need a level out of a hundred feet or if you can take it all the way to the ground okay so now let's talk a little bit about how we're going to use this with the minimum descent altitude and what we're going to do is look at the rules of an MDA then we're going to talk about a visual descent point we'll briefly look at how to calculate one and then we'll talk about a continuous descent on final approach and then finally we'll move from there into what happens if we go missed and then we'll go on to the decision altitude okay so let's take a look at a minimum descent altitude essentially this is the Colin is this the vo in Scottsbluff okay so the vor two two three in Scotts Bluff and essentially once you cross the final approach fix and if you're unfamiliar with the jeppeson chart the maltese cross is our final approach fix then we can descend down to our minimum descent altitude you'll notice that there's a couple things listed on here we have a V that's a visual descent point we have an M that's a required missed approach point and you'll notice on this Jepson chart we also have an angle with the dash and some dots that come after that is our vertical descent angle if we were flying a continuous descent and final approach but at the bare minimum what we need to do is get down to the MDA and then drive the airplane in and we can continue to remain at MDA all the way till we reach the missed approach point okay so again it's important to remember that you can't go below MDA in this maneuver so you need to start your power application to level the aircraft out before you get to MDA but then from there the FAA just says yeah you can continue along your final approach course at MDA all the way until you reach the missed approach point so looking back at that the question starts to become when can the airplane land and if we use this dive in dirt drive method it can actually be a little bit difficult to tell when the aircraft can land so for example if we see it start to see the runway here let's say we're three miles from the runway should we start our descent down well if we have the runway in sight but maybe not the Pappy or the Vasi it can be very difficult to judge your descent angle and if you look at this we're going to be it's significantly shallower than a 3 degree descent angle so probably not a good normal descent to landing the visual descent point is not published on every procedure when it is it generally lines up with or as close to the visual glideslope indicators but not always it provides essentially a normal descent down to the touchdown zone for landing so for a lot of transport category op variations the VDP is mandatory that's where they will depart MDA and descend down to the runway if they meet landing requirements that's their continuous position for a normal descent to landing the VDP and then all they need is required flight visibility and the runway environment and clear sight okay under par 91 we're not required to use the VDP at all it's just simply a little piece of advice but you really should think about it is not mandatory but put a really really important suggestion what it really means is if you haven't reached the VDP yet and you're flying a straight end procedure even if you see the runway you probably shouldn't get below MDA because you're not in a normal position to land the question is what happens if you're past the visual descent point so let's go back to this once you move past the visual descent point you haven't necessarily reached the missed approach point but if you were to try to descend from MDA who knows how steep that descent could be down to the ground the question is you're moving along too quickly to really figure out what kind of descent rate you would need okay you really don't know you know it is something where I can make it in a 700-foot a minute descent they made a 4 degree angle all you know is that you're high and so it's something you might try but what happens if you can't make that safe landing so that's why you'll see a lot of airlines a lot of transport category operators consider a VDP essentially mandatory if you do not have conditions to land and can if you can't start your descent by the visual descent point for a runway then they say you need to treat that is the point where you start your missed approach but of course under part 91 you can keep going all the way in all the way to the missed approach point once you meets the missed approach point that is where you're required to start your missed approach ok so again looking at a video P the concept is you would fly down final if you once you reach the VDP which may or may not be in the GPS flight plan so you need to think about that as your is your monitoring your pS distance if you meet landing requirements you'll start out of the way down and if for some reason you don't meet landing requirements at that point you would start your missed approach okay this also brings up up a good time for their first question okay got a first question here and that is how our missed approach points depicted on FAA plates good question let's pull this one up this is Scottsbluff que BFF in Collin you said this is the vor 2 to 3 that's a jet plate okay so what you'll notice is that the FAA plate does depict both the visual descent point VDP here but the missed approach point is drawn essentially by showing you on the profile view where the where the solid line on final transitions to the dashed line for the missed approach and the same thing is kind of indicated in the in the plan view but if you look at the profile view it's essentially where the solid line stops and we switch to the dashes and in this case we could look at the distance we have the BFF for tank here and that would be to measure it you need to be 3.1 plus 1.5 miles so 4.6 miles from the Scottsbluff Vortech that would be your missed approach point they don't draw it quite as well I think you know when you look at a Jepson plate let me go back here they do a little bit better job of indicating it with the strong M but again on an FAA plate you're really just looking for the transition from the solid line to the dotted and you might ask the question how could you determine when you're here well it doesn't have a certified DME distance you'll notice BFF does 3.1 from the Vortech so there's a couple things you could do on this procedure you still could use Det GPR DME or GPS from BFF at the same time you could use timing so you could look at those four point six miles figure out your ground speed and time it and you will notice if you look at a Jepson chart I actually give you the timing from the vor to the missed approach point for different speeds so you could either compute that mentally or you could use the the chart at the bottom of a Jepson chart again timing is I know has gotten to be a bit of a lost art especially considering that everybody is using our nav and GPS along with these to measure our distance but when I started flying instrument operations we did not have a GPS in fact there they they were just starting to put IFR certified GPS as an aircraft and approaches weren't out yet so it would be pretty common procedure it was common and standard procedure to start your clock over the mister over the final approach fix and time your way into missed approach point okay next question okay serge wants to know this with this approach that we've been looking at the view are two to three when can you initiate your descent to MDA is it immediately following the final approach fix good question search yes that's exactly right and you can tell that by looking at the profile view so if we look at the profile view you'll see once we leave the vor you can see then it shows us coming down to the minimum descent altitude and if you look at the bottom the MDA here is published with local altimeter setting 4500 feet the H is the minimum descent height which is an AGL number after that so that takes you down to 533 feet that's when so you can start your descent to that altitude as soon as you cross in this case the vor that's your final approach fix from there there's a couple techniques so we talked about this visual descent point and essentially we use the old Ivan drive technique and on the dive and drive technique you're going to go down to minimum descent altitude and then you're going to drive the aircraft in at MDA on final approach until you either reach your visual descent point and either land or can't and you may elect to go missed or until you actually reach the required missed approach point where you could go missed the other option that you have here is to use the FAS published vertical descent angle so the vertical descent angle essentially is an angle that will take you from the final approach fix down to the runways touchdown zone and it will take you through your minimum descent altitude it doesn't guarantee any obstacle clearance once you get below MDA but if you fly that vertical descent angle and you meet requirements to land once you get to MDA you could continue it all the way down to the runway so essentially you could think of it is a perfectly stabilized descent will do a we're actually gonna do a show on this at Oshkosh and we'll do a separate course on this another night but essentially you can see that vertical descent angle is published right here so I could either choose my own rate drop down level out at MDA and drive it in or I could fly this 3.1 degree angle from the final approach fix down to the NBA and if I meet requirements tool and you'll notice that angle takes me right through my visual to set point I could hold that angle all the way down to the runway you'll notice on a jet chart they tell you that descent angle of three degrees they give you it each one of your speeds you're required to set rate and keep in mind when we're doing that not all of these are three degrees you'll find quite a few of these vertical descent angles might be three and a half or four degrees they are not necessarily a normal descent so if you look at them in Aspen they can be up to seven degrees and they get six and a half there and steamboats seven degrees which I would say for most aircraft you still a 7 degree descent would have a hard time landing straight in but you could fly tear those down okay so here's a good question what happens if your fall a procedure that does not have a published visual descent point so let's see if we can find one of these okay so in this case the vor DME to runway five doesn't have a published visual descent point so maybe you want to try to compute one and so if you wanted a plan on a standard 3-degree glide slope that's a pretty good way to do this one of the tricks that you learned is you plan on a hundred feet per nautical mile for every degree of glide slope that you want to land at so you could either look up the the vas at the airport and see what it is or you could simply if you want to plan on maybe a three degree descent you could look at that okay and so if you were to do a three degree VDP what you know is for every mile back from the runway you go you'll go up 300 feet so now we just need to figure out how much distance we need to lose between the minimum descent altitude and the runways threshold okay so one of the really easy and simple ways to do this is just to take a look at the minimum descent altitude and height so if we're using the local altimeter setting it's 528 feet okay so we're gonna descend down 528 feet and the easiest way to do that is to take 528 and divide that by 300 300 feet per nautical mile so 528 by 300 you're gonna end up with one point seven six so in this case you could design your own visual descent point right here and that would be one point eight miles from the runway and that visual descent point would give you a three degree descent down essentially to the runway threshold now we've got a question coming up and I'll grab it in just a second but it's important to keep in mind that when you compute your own V DP or you use the FAA s publish VDP neither of the two protect you once you go below your minimum descent altitude there could be obstacles in the middle that flight path there could be a tree or a pole or a hill that sticks up that prevents you from flying that descent down to the runway even though you planned on it so you need to be visually ready to avoid any obstacle once you descend down below MDA even though you're trying to fly a normal glide path there's no assurance that you can one of the things you can use is if as your Pappy but you need to make sure you're within the cermets limits and you need to check the airport facility directory to make sure those haven't been revised but essentially if you create your own VDP or if you use one of the published ones once you're below MDA as always it's up to you is see and avoid any obstacles okay what's the next question all right next up by question is this this following the CDFA angle guarantee passing through the visual descent point they eye that's a really good question VIPs are older than CD FAS I believe that they will be co-located now but I cannot guarantee it a CDF phase are a fairly new development ideally they would be located together I have yet to see a case where they're not but there might be a scenario where you find one that doesn't quite line up it's important to keep in mind with a continuous descent the final approach that all they're doing is drawing along from the final approach fix that crosses all of your step-down requirements so it won't take you below a step-down if you fly that angle that you'll you'll stay above all of your minimums then takes you through MDA down to the touchdown zone that angle could be incredibly steep the FAA doesn't necessarily say hey this is something you could actually fly and let's let's take a quick look at one I'm gonna pull up steamboat we'll start by looking at the FAA one here so this is the steam bat steam bat steamboat RNAV procedure you'll notice it's a circling only procedure even though it really is fairly lined up with that runway and the missed approach point if you look at it is right at the runway threshold but the reason it's a circling procedure is because the vertical descent angle is seven point seven five degrees departing pixxa you need to descend Peck's is our final approach point your final approach fix you need to descend at seven point seven five degrees to make it down to the runways touchdown zone okay well let's use a little basic math okay the descent altitude minimum descent altitude in category A or B is 80 140 and you're flying from PEX a' you departed about nine thousand seven hundred feet MSL so let's say you wanted to fly this approach route 100 knots indicated standard speed and sr22 we got to add two percent per thousand feet MSL roughly of true airspeed so even though I'm indicating a hundred knots I'm really going a hundred and twenty knots true and let's say the winds are calm so now my ground speeds about a hundred and twenty knots that's about two miles a minute sixty knots is one mile minute 120 knots is two miles a minute if I have a seven point this is seven point seven five so let's just say roughly I would say maybe seven point eight or eight degree descent angle very eighth degree descent angle that's eight hundred feet per nautical mile I'm going to nautical miles a minute so I need to descend around 1,600 feet per minute to get from pecks ax down to the runway threshold somewhere between really fifteen and sixteen hundred feet a minute because it's seven point seven five so somewhere between fifteen and sixteen hundred feet a minute and I'm doing that in bad weather down to probably an obscured runway not a very safe descent rate so when you see a CDFA published that does not necessarily mean that the angle is safe to fly we're safe to land from it just simply means that it will get you down to the threshold or the touchdown zone okay next question okay Daniel wants to know this when can you descend from your MDA on a non-precision approach okay so again we're going back to those three things you need to be in a position a continuous position for a normal descent to landing when we say the word continuous what we mean is you're not going to level the airplane out so we're not going to go dip below MDA because we see some lower clouds ahead of us or like I'll do just get like a hundred feet below MDA and then we'll level out there and fly it in until we need to land nope you need to be able to maintain a continuous and normal descent to landing you need to have the required flight visibility so as soon as you can see far enough from the airplane down to the runway to go yeah I can see more than like on the steamboat approach the one and a quarter miles that I need a land okay you have to have those two things and the number three as soon as you clearly have part of the runways environment in sight okay so any of those ten items we talked about that's when you can descend so for her to go back I'm gonna jump back in at Scottsbluff animation you know the reality is you could legally start your descent at the visual to set point you could say well I don't know I felt like like I was in a normal descent in front of that it's shallower than three degrees it maybe be two and a half but if you have the required visibility in the runway environment in sight you could start down early and you could legally start down late as long as you consider it to be a normal descent to landing and you have the runway in sight and you have the required flight visibility impracticality a lot of new pilots as soon as they start to see the runway environment they go yeah I can see I got the visibility they'll start leaving MDA to land and that's a bit of a mistake you know because we get excited oh yeah I can see it let's go to an Atlanta we realized we're not even close to the visual descent point yet it's better to stay at MDA till you get to the V DP and use that optional VD pita land and if there isn't a VDP on a non-precision approach it's always a good idea to calculate one makes things a lot easier otherwise if you didn't calculate a VDP and you can see the vasily pappy once you've got the pappy in sight and you have the and you have the visibility requirements that's oftentimes a good time to descend once you're on the pappy or the vasa glide slope that can make it an easy way to fly in okay this whole brings up the scenario of what happens if you continue past the visual descent point and there's a lot of reasons why commercial operators will prohibit approaches after the VDP there's a lot of reasons while they while they'll require the crew to start the missed approach point at the VDP keep in mind they can't turn yet they need to continue straight along final to the missed approach point but they will immediately start their climb and one of that is so one of the reasons a lot of transport carrier pilot or transport category pilots will start the mist at the VDP is so they don't try to make a landing that you couldn't actually perform okay so what would happen if the aircraft starts down and then realizes it can't make the landing and you decide to go missed what you can see here all of these dashed orange lines that is your required climb gradient and as I start my missed approach point the problem is I'm no longer or start my missed approach below MDA I am no longer afforded any obstacle protection and it's not that I need to get back up to MDA before I get obstacle protection I actually need to cross that climbing plane before I get obstacle protection so that's the concern if you go missed if you execute a missed approach below MDA or past the missed approach point you're no longer afforded obstacle protection and you need to get back on the missed approach course and you need to be above that climbing required climb gradient before you've got safe obstacle protection so keep in mind that climb gradient time's at 200 feet per nautical mile and in a lot of places if you're flying a light single-engine airplane you know if you're going 120 knots that would be 400 feet per minute you're probably gonna be able to climb faster than that unless it's high da but maybe not much you might only be able to climb at 500 or 600 feet a minute so it could take you a very long time to get the aircraft back up against that above that 200 foot pro nautical mile climb expectation okay next question next up Joel wants to know this does the VDP provide obstacle clearance great question it does not the VDP only says that the descent from MDA to the runway would be fairly normal normally about three degrees though they're oftentimes tied to the V GSA so if it's three and a half you might find it you know the if the vgs is programmed to three and a half degrees the VDP might be three and a half degrees but it's there to give you a normal descent to landing it does not mean that your landing gear won't go through a bird's nest on the way down and so this is one of the things this really surprises pilots when we start to talk about what level of protection you're really afforded below MDA or even da and the answer is not much now on a ILS they do certify that the obstacle plane is clear they go through and measure that but that doesn't mean that a tree might have grown in between there think about it you know trees grow especially in you know Pacific Northwest they can grow very very quickly so anytime you go below MDA or da you are afforded zero protection you need to be looking out for obstacles all the way into the runway even if they've surveyed the obstacle plain clear the FAA basically says it is 100% your responsibility once you go below your da to see and avoid all obstacles again that's one of the reasons why if you really can't see anything you want to be careful about descending below MDA because you know I kind of see the runway okay can you see the trees and everything else do you feel safe that you're not going to hit any obstacles that's a key point okay next question we do but they're all iOS questions okay we'll get to that in a second what I wanted to kind of emphasize here when we're looking at this missed approach point and descending below MDA again if you're an instrument training you really never think about this because you're wearing the plastic cloud most of the time and you can try to make the air and the landing and you know the approach and so we kind of just try to dive it all the way into the runway once you see the airport we don't worry about vdps but in the real world there is significant danger if you try that and you realize you can't land and keep in mind you know a lot of procedures will take you down to you know 400 feet above the ground and it's kind of easy to estimate your descent rate though in bad weather it can be hard then you'll have other procedures like the approach into steam into Telluride or in Aspen that they get you a couple thousand feet above the ground there is no way that you can visually estimate in bad weather whether you can make that landing and in airports with high MDAs you also have lots of terrain and sometimes increased climb gradient requirements on the mist so you really need to be sure that you can stick the landing when you descend below MDA that's really really important because it can be very hard to get back above your climb gradient requirement if you start that below MDA or if you start that past the missed approach point okay calling you want me to go into da or take the question okay let's go for it okay so we're gonna start off with Danny here and he wants to know this can you shoot the approach and land if the reported visibility is less than what's required on the chart good question the answer is under pardon anyone absolutely under part 91 you can fly a procedure you can start a procedure no matter what kind of weather is reported it can be reported zero zero and under part 91 you can start that procedure okay and people say a lot of people who are experienced with the airlines just say wait a second I don't know if you can do that part 121 and 130 five are completely different they need the weather to be above minimums before they can start the procedure but under par 91 you can start the procedure while the reported weather is below minimums and the FAA has nothing against that you'll hear people say oh and although come after you for saving a careless operation or careless and reckless no they want it you can start the approach even with lower than minimum reported weather okay what you you can land even with lower than minimum reported weather you need to have the required flight visibility you need to be you need to be the judge okay so people go well you know well the FAA come after you if it's reporting a quarter mile and you made a landing but you could see all the way down the runway and the answer is first of all the probably never know okay second of all those are the kinds of things that the FAA usually finds that about because you have an accident and then they start to look at it but the reality is as a pilot you want to trust your own judgment and so if you're flying in in a sauce is reporting a mile and you pop out of a layer and you can clearly see for miles yes you can continue to land the airplane on the runway the next thing that I would do is I would file a pilot report that really just to protect you but to let other pilots in the area know that the weather isn't necessarily matching the report especially if an aircraft's looking for an emergency alternate or something like that it's good to have accurate weather reports once you get into part 121 135 those rules change but under part 91 the reported weather is essentially advisory on an approach and it's your eyes and your flight visibility that matters okay next question okay next up from Joel he's got a really good question here and it has to do with what you were showing before with going below MDA and then going missed he says this don't you still have departure obstacle protection from the runway you're approaching just like you would if you're taking off from that runway that is a great point and the answer is absolutely you do you would you would definitely have the diverse departure area ODP protection what really starts to happen though is the ODP require Mintz first of all if there is a textual departure procedure may not line up with the missed approach point in path and so even though that's been evaluated for the airport it may require a departure to do something different and so your missed approach path may take you outside of the safe limits there are cases where approaches will take you into a runway that you are not allowed to depart from under IFR so you're right and and in many cases you would have departure area obstacle protection that would protect you on the missed approach path as well but not in all the the airport's departure may require you to go in a different direction the missed approach point or path may not follow that and so you could still be in an area where where you're dangerously close to obstacles okay let's take a look at da we talked about MDA and let's talk about the difference between MDA and EA it's not just the difference between a non-precision approach and then a precision or approach with vertical guidance it's really how we treat it because in a decision altitude we're going to follow our electronic glide path indication all the way down that could be glide slope or a glide path and in our nav unit we're going to take that all the way down until we reach our bottom decision altitude that is where we make our decision to continue landing or initiate the missed approach so what the faa is acknowledging is that when we do this will actually go just a little bit below the decision altitude here I'm gonna do that like this we're gonna go just a little bit below da before we start climbing again and so when you think about an MDA when you're flying it you're gonna start the power up you're gonna start the level off and gently bring the aircraft down to MDA so you'll let that descent rate generally shallow out so you don't go below M da da is different you're gonna fly that constant glide path holding that descent rate and tell you get to that altitude and Annette that altitude you're going to make the decision in it that altitude you either bring the throw up and take the aircraft around or you can continue down to land and so as you do that the aircraft will briefly transition below da okay next question Serge wants an L RDH in da the same they are they're just expressed in two different types of altitude right your da is your decision altitude and your D H is your decision height your da is MSL your D H is AGL and we really start to think of D H is in aircraft that use radio altimeter x' cat 2 and cat 3 operations where your radio altimeter will tell you how high you are and that gives you a much more accurate reading your barometric altimeter and so you'll hear D H is there you know D H 100 feet or 50 feet but you can also say yeah my decision altitude is 8,000 MSL and to my decision height is 200 feet AGL in category 1 operations we don't use decision height as much simply because we don't have an accurate way to measure it in most of our aircraft next question brand wants to know this how do you know where the missed approach they excuse me how do you know where the missed approach point is if you're using an ILS instead of a GPS non-precision missed approach point great question if you're flying an ILS the missed approach point is your decision altitude it is not a specific point on the ground it's your decision altitude okay so what that really means is when we think about an MDA where we level off we have no legal obligation to go missed until we reach the published missed approach point on an ILS on the other hand once you reach da you are legally obligated to start your missed approach procedure if you do not meet the requirements to land and if you do not decide to continue down to landing so on an ILS your missed approach point is always your decision altitude on any approach with certified vertical guidance l Navi nav Baro V Neff LP v ILS MLS any of those certified vertical guidance item your decision altitude is always your missed approach point okay so let's just take a look quickly in an example of an ILS I'll grab the ILS into Newport okay so if you look at this here you'll notice though you could also fly it as a localizer and yep you could do the localizer which has a different decision altitude and so in that case I'm actually in use it's a better example I like how Jefferson publishes this because it makes it very very clear but you can see in that case they've drawn this missed approach point here at DME zero point seven from Newport and if you were flying this with the GPS you would see D zero seven is the missed approach point if you were flying the ILS and you reach decision altitude you will reach it prior to that missed approach point however on the ILS that's where you need to start the missed approach that's where you will start your climb however you will not start your turn okay in this case you would straight up to a thousand feet than a right turn but in general you won't start a lateral deviation from the final approach course until you pass the non precision missed approach point so essentially you wouldn't start turning until you've reached the map at D zero point seven so even on an eyeless around an ILS you take it down to da and I don't see anything I got to start my mr. proach I start my climb immediately on the missed approach procedure but then I would start lateral navigation once I cross the publish missed approach point okay next question alright J wants to know this he says I've been told that on an LP V approach you use da because it's considered a precision approach I think you indicated that you should use MD is that the case or is it da no you're right it is da so an LP V so let's go through those the L Navi nav an LP V or an ILS are all approaches with certified vertical guidance and so if you look at the minimums published for them they are a decision altitude minimum so you'll use a DA where that starts to change and get confusing in the GPS world is plus V so if you've ever loaded a GPS procedure and you see that it says plus B that's advisory vertical guidance plus V is not certified the FAA doesn't look at it they have nothing to do with it plus B guidance does not change your MBA you still fly down to a minimum descent altitude but if you're flying in iOS an LP V or an L Navi Nav then you're gonna fly down to a decision altitude and and again you know one of the things that we talk about is once you get to that whether it's a da were if you're down to the M mr. Pro Tour MDA if you decide to go missed prior to the missed approach point you want to start your climb but continue flying along final until you cross the publish missed approach point and then start flying the missed approach procedure okay next question you just answered the question but I'm thinking maybe we can just draw this out on an approach that wants to know if your printable and here's his question and it's actually a really good point to bring up here what he says is here if your personal minimums are higher than the DEA or MDA for that matter what's the best way to figure out where you start your missed approach can I climb early can I turn early so that is a perfect question first of all you can always climb early you can always start your climb to the missed approach altitude and I'll give you a really good example Colin and I are flying a back course in was in Salem or Corvallis sail yeah and we turned out of the back course and we were filming it so the auto was flying actually on this one and all of a sudden we started to get course galloping we had just left the final approach fix we're even close to end the MBA but the back course was swinging around about half scale left and right and of course now the autopilot is trying to follow it and we're in IMC and so you know I took it off and kind of stabilized it you can just see this the localizer is just flying left and right now we're like yeah we're not going to continue this procedure clearly because it's going to be impossible to track the localizer so the first thing we did is we started our climb to the missed approach altitude and then we did our best to kind of hold the center of that low course where we called ATC and let them knew we were flying a missed approach but that's a key you can always start your climb to the missed approach altitude you need to remain on the lateral course all the way until you reach the missed approach point then you can start your turns and start flying the missed approach procedure and if you get high enough like what happened in court I think with salem or koalas approach started vectoring us early but otherwise you may find that you're flying that missed approach procedure almost at your top missed approach altitude which is which is fine the key thing is that obstacle protection is really only provided on the route so if we were to take a look at let's take a look at this Newport Oregon ILS okay let's say something went wrong maybe we maybe we have a 400-foot personal decision altitude so you know that's maybe right here and we start that turn out early there is no obstacle protection there and there could be a tower or something like this on the on a jetty in the Columbia River and so because of that you would never want to do that instead what you would do if this was the point you elected to start your missed approach is you would just climb again continue until you cross that published missed approach point runway threshold or DME point seven from Newport and then you would just fly the published missed approach higher than higher than expected essentially okay next question okay next up Robin wants to know if we descend to a hundred feet above touchdown zone elevation like you see the approach lights but you don't see anything else when do you go missed that it's a really really good question the answer is you're kind of in a gray zone down there and this is something I always caution people again you know if you don't really if you don't really see the approach lights if you just kind of think you see them you may not want to go down because you could end up outside of that obstacle protection and in a tough zone but the answer is if you do start that descent with just the white lights in sight you would go mist under a couple scenarios number one you lose sight of those white lights and you do not see the runway markings so that would be one you lose that visual reference as soon as that's gone you need to start your climb in your missed approach procedure okay number two your flight visibility degrades so let's say you're landing and miss that starts to turn to fog you could see down that six thousand foot runway plus some and then all of a sudden you can only see about five hundred feet in front of you and you don't meet visibility requirements then you would immediately need to start your mist approach and then if at any point in time you're like yeah I'm no longer in a normal position to descend so you see the runway lights and you realize this is a short runway and there's no way I'm going to be able to descend down anymore I need to start my mist approach essentially you know the reason they put those white lights there is the idea is that you'll be able to see that at least the white runway lights or something by the time you get to the end of the approach lighting system but if you can you know if you lose the reference to the approach lights and you can't see anything else you need to start your mist okay next question next up and this goes back to the non-precision approaches what Robin wants to know this if the distance to the threshold from the VDP is greater than the available RvR flight visibility how do you proceed that normally would not happen but if it does you cannot you couldn't use the VDP because at minimums essentially and it could I guess it could happen I'm trying to think of an approach where I've seen that it could possibly happen but the reality is if the weather was at minimums you would not be able to use the visual dissent point and one of the things to think about oftentimes with these procedures is you know a circling option if you if you still meet if you meet circling minimums you could always plan to do a circling approach which allows you not to try to fly it straight in but allows you to maybe join a pattern and in some cases that actually can make landing easier but the reality is if the weather is right at minimums and you reach the VDP and you don't have the required visibility or you can't see the runway ahead of you you couldn't use the VDP you have to keep flying along MDA and then decide once you do see the runway can I still make a normal descent to landing next question okay you've got another really good one here and that is I agree with everything you've said about LP vs and using da or D H however how do you reconcile that with the fact you can't use an LP V for the 602 precision minimums for an alternate approach that's a great question when we started putting our nav procedures in the National Airspace System we really screwed everything up from a point of teaching because everything was so simple before our and a half I mean precision approaches were approaches with glide slopes and there were ILS and MLS's and that was the end of it and at everything else fell into the non precision world and then as we started adding L Navs in L PBS it started to confuse people so I did myself included so the FAA created the concept of I think ICAO did as well approaches with vertical guidance or AP v and essentially they're not a precision approach so they cannot follow the precision approach minimums but you're still using an electronic glide slope guidance that glide slope or glide path is being generated by wasps in the GPS or by berra weighting as opposed to by a glide slope indicator or a glide slope radio but that vertical certified guidance means that you can fly down to a DA the reason those are not considered precision approaches has nothing to do with the DA and everything to do with the certification or redundancy and equipment requirements for an ICAO precision approach essentially an LP v doesn't meet all of the ICAO requirements to be considered a precision approach and that could be a variety thing so be runway or all kinds of stuff like that and so because it doesn't mean I can't require Minh steuby considered a precision approach you cannot use precision alternate minimums you need to use non precision minimums if you really get into it in the aim essentially what they say whether you're wass certified or or not when you're considering an RF procedure for an alternate you need to plan on using either the L Neve only minimums or if your aircraft is Baro vina have equipped you can consider the Baro V nav minimums and essentially what they're trying to say there is don't count on GPS for an alternate glide slope we're not sure if you'll be able to get it so they want you to be able to land off the non precision minimums only the reason Barrow vina have is thrown into the aim there is because Barrow V nav is entirely independent essentially of GPS it just uses barometric pressure to draw a barometric glide path down to a decision altitude but that's why they're using non precision minimums because the FAA saying yeah you know yes if you've got the vertical guidance you can use it down to the DA but there's a chance it may not be there wasps could be out and so we don't want you considering that for an alternate okay next question next up we're gonna put you on the spot for a couple questions but I think we're gonna be okay here we have a couple specific questions about approaches at different airports I'm so the first one is at KD a B and the question is this we're looking at the ILS the ILS and Lok to seven left at KD a be and here's Ian's question he said if you're shooting the localizer how would you correctly identify the so prefix in a g1000 equipped aircraft okay so great question so pre is a named fix in this case and so in Ag 1000 a crab to aircraft I would use the first of all you would load the GPS flight plan so let's quickly talk about how we're bouncing back and forth between cameras sorry about that yeah let's just quickly talk about are now substitution because that's going to help clarify the answers here because you're asking about a g1000 okay so in a g1000 aircraft as long as the aircraft has GPS that meets requirements you've got ram and wasps and everything is running okay you can use our nav to substitute for V ORS and ndb's and distances from vo ours and ndb's and so therefore weekend distances from name fixes so we can always use our nav and I use the word RN f we always equate it to GPS but there are other systems that it could be as well so our nav you could use our nav that's properly certified g1000 style to identify any of the named fixes on a procedure so if I'm flying a procedure in Ag 1000 equipped aircraft I will always load the procedure through the database and the reason I do that even if I'm going to fly the entire thing using VHF green needle navigation is because the distance information that I get to each of those name fixes is legal and usable even if it's just a VHF based procedure what I cannot use aren't have to do is legally navigate a published localizer course our nav is not suitable or or approved for navigating a localizer course so let's go take a look at this if I was to load this procedure through the G 1000s database and then fly this green needles I legally need to be green needles once I turn on to the lo course so let's say I flew let's just take a look at the arc I love arcs so you know I could use aren't have to navigate this arc but the moment I turn on here you know what I'm gonna make it really high-tech and our nav will be red so I can use our nav all the way along the arc and the moment I turn on to the localizer now I need to be green needles through the localizer procedures so I'm green but I can use arnav's distance to tell me once I'm at so pre okay so what happens if we didn't have that well you'll notice looks like on this there is no DME from the let's see yeah there's no DME from the ILS and so you'll notice or no DME yeah the DME hears from om n which is Ormond Beach and offset vor so you can't use DME to identify so pre you can use sorry the crossing radio so om n radio one seven nine okay and the easiest way to do this in a g1000 equipped aircraft especially in annex i is to put the vor up on your bearing pointer so typically when I'm flying with the g1000 equipped aircraft and I'm flying a procedure I usually fly from the right seat I always have bearing pointer number two set to the GPS so that the distance information that bearing pointer number two and the Waypoint always relates to my supply plan I like that because it's in the lower right corner of the HSI and so as I'm scanning I don't have to scan up to the top by the radio bar I can keep my eyes centered on the HSI altitude and airspeed tapes and it keeps my skin really really tight and I got my GPS distance right in that bottom right corner so that would tell me when I'm getting up is over E and then the other advantage with the bearing pointer I don't know if you've ever had this problem but when you cross the missed approach point you start that you look down you see point two okay wait a second is it point two miles to the missed approach point or am I just a little slow and I've already crossed over it the advantage about that GPS bearing pointer is it will flip upside down and tell me that the point is behind me now so I like that but then what you could do is you could put warm and beach in nav one and you could set bearing pointer number one over to Ormond Beach and once that bearing pointer hits one seven nine degrees then you know you're at so pre on the g1000 and excise it actually tells me my burying in numbers I do not know if the original G 1000 does it but that would be another way to identify it the missed approach point is a little bit tougher with our nav you could simply dealt with our nav there will be a runway missed approach point so in this case it would be our W 0 7 or RW 7 would be the GPS is missed approach point and essentially that will it just takes the lateral distance so two point nine plus one point nine and it puts a missed approach point there but if you didn't have our nav if your GPS was out how would you figure out that missed approach point because there is no cross radio from Ormond that goes to the missed approach point all you've got is distance and if you look down here it's four point eight miles so if you're flying the procedure at 90 knots with no wind it's three minutes and 12 seconds from the final approach fix full ugh down to the missed approach point um even with the g1000 if you didn't have ram or wasps if you couldn't use your GPS then what you're down to is the clock okay next question next airport that we're looking at david's got a question about the Van Nuys Airport which is kvn why we're looking at the ILS Zulu two runway one-six and this is really interesting I was just looking at it over here his question is this does Van Nuys have a miss approach that requires a descent if you start the missed approach early and I'm just gonna if you haven't seen it already Alex here if you look at I'm looking at the ball out the plan view right there it talks about the and if you look just above it on the plan view it discusses the missed approach so let's take a look here that's a great great now this is something I've never seen but they hint is in the missed approach verbage so let's just take a look at this missed approach verbage right here mr. proach when you bring up a pencil there we go climbed across d 1.5 vny south of the van noise vo are at or below 1750 then climbing left turn to 4600 outbound on vny VOR 152 to here v or DME point 8 v NY then direct s mo VOR and a patent s more view or 1 267 and then inbound on the v tu r VOR 0 8 7 to V T WA and hold this is well those procedures you really would want to fly using R NF or have a good copilot who can spin those for you but I see exactly what they're saying in this case they're probably using that at that that altitude restriction for traffic separation so this is a very rare case figures that it's advanced in California this is the kind of place where you'd find something like that the reality is if you executed your missed approach early then you would still need to comply with the missed approach altitude requirement so if you started your missed approach above that you would need to descend down to 1750 feet and hold that or slightly below until you meet that climbing left-turn requirement so this is really uncommon but what it does bring up is the fact that in the National Airspace System most things are fairly standard but not all of them and so you'll find some kind of funny things like this someone off procedures where you look all over the United States you won't find another one even remotely like it but if you read the missed approach it makes it very very clear and this is another thing people ask when do you brief your approach I don't usually brief my approach on departure because oftentimes we're on a three or four hour leg and that's a that's a lot can change you don't even always know which approach you use I do make sure that there are usable approaches at the airport in the runways long enough but I typically brief my approach once I start my arrival so about a hundred maybe a hundred and fifty miles out sometimes and I get that briefing done very early because if there's something like this in a missed approach plate I want to be able to catch it well I'm basically sitting happy and cruise on a basic high-altitude descent I don't want to try to figure this out as I'm crossing an initial approach fix so that kind of the training world which we're all used to where you're doing approach after approach after approach and you're literally given the briefing right as you cross the initial approach fix in the line flying world when you actually get out there and use those instrument ratings you want to brief early I like to get the weather really early and if I can't get the weather right away from from a saucer a wasp because I'm out of range I'll use a DSB to give myself kind of a pre weather I still always pick up the minute weather but then I start that briefing early so you can pick up stuff like this okay next question okay we're back to a bear of vnf question here and it's this isn't the Barrow V Nav created and carried over from using the older and now outdated GPS systems I don't see the Barrow V nav in most GA that use Garmin g1000 G 2000 the five 30s in the four 30s with wasps can you explain good question it is a carryover but it still has a purpose and the purpose is if waswas to go away it gives you another option so let me pull up I'm gonna pull up a Barrow NDB never approach how about I'm go to Eugene and I think it's C yeah okay so if we switch to the I've had you're going to see three different landing minimum here again you're going to see a LP v decision altitude an L Navi nav decision altitude which is about 30 some little under 30 feet higher and then a significantly higher LF only minimum descent altitude and so L may at vina F doesn't get as quite as low as the LP V does you know it's it's still above that but it is definitely lower than the L have option so when will we use this let's say wash failed and you still were able to generate rain but you could not get wasps again the two are separate and a g1000 system can do both so the aircraft is able to provide rain but not able to provide wasps it can't provide lpv that's when you would see El Naveen f so when you go to load the procedure you'll notice that it never says l navi nav and that's because the GPS knows right now hey I've got wasps I don't have any problem so I'm going to show you an LP V if for some reason wasps had failed if it did not have the satellite information to provide wasps when you went to load that procedure you'd actually see L Navi nav and the interesting thing is and we'll do a video on this shortly if you were to lose wasps as you started the procedure on a g1000 outside of 60 seconds from the final approach fix it will roll into l Naveen F as long as it still can provide rain so essentially you know if you're on the intermediate segment you're still more than 60 seconds from the final approach fix and the wasps satellite goes out and you're just left with basic well G PS and it's like okay yep I've got rain you'll see that HSI will switch from a purple lpv it'll go to a yellow L novena have to catch your attention and then it will go back to a purple L navi NF so you know the question is is it a carryover kind of but really what you want to think of it as is a fail-safe if for some reason you can't get wasp but you still have basic GPS rain then your aircraft if it's Barrow vina have equipped will be able to provide L Navi nav and if it's not Barrow via have equipped then it would fall back just to L nav and of course fuse all of your satellites and you have nothing that's a great time to use the minimum safe or minimum sector altitudes okay that's all the time we've got for tonight but let me go back to our presentation here because our Oscar schedule is out we're going to be speaking at the EAA pilot proficiency Center that's where they have all the simulators it's kind of on the main plaza we're going to be speaking Monday Tuesday and Wednesday doing three live classes all of them are at 12:45 it's the last class before the air show so you have all the opportunity to have lunch and then show up and sleep through these classes the first one on Monday is mastering crosswind landings the second one at Tuesday's obstacle departure procedures and then the third one on Wednesday is how to get comfortable with stalls they're completely free there they're presented in partnership with EAA and jeppesen I really love doing them it's one of the few times we really get to stand in front of a large group of people and do something that's truly live so if you're gonna be at Oshkosh Monday or Tuesday and Wednesday really hope to see at the EAA pilot proficiency Center there's no need to RSVP you just need to show up and last but not least if you learn something if you like this video tonight press like it helps Google and YouTube know that these are quality videos and increases our search rank and we always like to hear your comments so send us email is an info of old method to come or support a pull method comm there's also a link in the description tomorrow night on IFR on bolt method live pro pilot we're going to talk about critical Mach numbers and sweep back a little bit so if you're thinking about going to an airline and you really haven't ever had a intro into high-speed aerodynamics we're gonna give you a good overview of wing sweep in critical Mach they should be able to help you out in a regional airline interview otherwise if we don't see you tomorrow have a great night we'll see you in a couple weeks [Music] [Applause] [Applause] [Applause] [Music] [Music] [Applause] [Applause] you

Channel: Boldmethod

Views: 43,977

Rating: 4.957963 out of 5

Keywords: MDA, minimum descent altitude, da, decision altitude, dh, decision height, map, missed approach point, ifr, learn to fly, instrument flying

Id: cpl_RDVKKfQ

Length: 85min 37sec (5137 seconds)

Published: Tue Jun 25 2019