alright folks welcome to another episode of the FNG the flying new guy which is Jason if you're not familiar with the format Json is going to get his private pirate certificate he's one of our employees and uh we are doing ground lessons with him Tom right here is our CFI on staff uh certified fly instructor and then of course I'm also a fly instructor so we're going to be grilling Jason over these lessons over time and today we are talking about flight instruments and this might take maybe even two different episodes to do that we'll see how it goes we try to keep them to about a half hour episode so you guys can uh can can watch and learn at the same time this is a slightly different environment what you would see in your uh in your flight school maybe when you do ground lessons with your instructor there's no Penny laying on the ground there's no comfortable seats usually you're in a cubicle with a white board but we're doing this more comfortable and uh yeah let's get uh let's get started with the flying instruments and I think one of the important concepts with the flight instruments especially with some of them is talking about the pressure outside what's what's the atmospheric pressure what what does that what does that look like what's the the concept of it's the weight of air the weight of air okay the weight of air and then how is it measured um in what industry that's right a lot of different ways there's a bunch of different ways there are a lot of different ways so in aviation how do we measure it typically inches of mercury inches of mercury all right so that's going to become important when we start talking about some of these instruments now there is a uh there's a reference that we use do you remember what what that is the standard dates the standard day yeah what's what's the definition of a standard day um 15c 59 Fahrenheit sea level and 29.92 inches of Americans of mercury yep why is that important why is that reference important that's what we base all of our calculations off of essentially it's a hypothetical standard that very rarely if ever exists and so so based on that and you're right it rarely exists based on that how how are the changes in pressure going or even temperature going to affect us why do we care um changes in pressure and temperature affect performance and what your altimeter is going to read okay yep that's really good no I like that answer good I do too so um what what's what's the worst possible scenario as far as temperature and pressure in relationship to standard day like colder warmer what's better warmer is worse warmer is worse um higher or lower pressure is worse lower pressure is worse so I always tell people yeah go ahead and humidity and humidity as well yeah so we haven't really talked about humidity because it's not um it's something that we need to account for to a certain extent but it's not something that we pay too close attention to an aviation interestingly I think the uh the effect on performance is is not significant enough that we usually worry about it although you should you know when you notice the higher level of humidity but yeah I always tell students a very hot day in uh in Florida in the middle of a hurricane that's right that's high low pressure high temperature um okay so talking about these flight instruments we have and when we talk about a six-pack in this case just to keep it simple um there's two different types of instruments because they work on two different systems you remember the two different systems that they work on the Peter static is One beta static is one the others are gyroscopic gyroscopic system okay all right so let's get started with the pedostatic system what does pedostatic mean it uses a static port and a pitotube to calculate differential pressure okay and then displays certain information based on that differential pressures okay so pedo the pedostatic system is how many instruments three three it is your airspeed indicator your speed indicator your altimeter altimeter uh vsi vsi vertical speed indicator okay um which one of these works out of the static port all three all three yes it's not a trick question which one of these well which ones yeah sorry uh which ones in parentheses s of these works out of the pitotube the um the airspeed indicator only yeah okay so I'm thinking about how the are you sure yes I'm thinking about how the systems actually work I'm pulling the DPE are you sure yeah I'm sure okay okay all right let's move on um so so the pitot tube does what the pitotube measures what how much air is being forced into that Port essentially right there Ram Air ramire yep and it gets into that little tube now they all look different on the 172 it's kind of a thing that comes out yeah on the uh on the piper it's more of a like a thin yeah it looks kind of like a transponder fin yeah so they all can look different um how how does the altimeter know how fast you're going the altimeter doesn't know how fast no trick questions that was a trick question that was a trick question how does it know how does it know how fast it it calculates the difference between your Ram air pressure and your static pressure okay why do we need a static pressure why not just use the rhyming or pressure because variable pressures and or temperatures is going and altitudes is going to give you a different amount of air that can get into that Port yep yep What's um when we talk about that air speed that you read on the instrument what is that called there's different types of air speed what's that one called uh should be your calibrated airspeed nope no almost almost what's indicated on the indicated airspeed so what's calibrated airspeed so calibrated AirSpeed is pretty close right calibrated is the indicated AirSpeed corrected for installation errors okay there's a tube right that takes that air that that Ram air pressure into the instrument right you lose some of that along the way the instruments isn't calibrated on its own so it's accurate at one air speed and there's usually a chart in the poh that's going to tell you what that AirSpeed is because if you think of a Cessna you think when we're doing I know you haven't flown yet but like when we're doing slow flight we're at a high angle of attack we're at a really low air speed so our pitot tube is pointed up like this and if our air is coming like this it's not going to be accurate if we're at 90 knots which I think in the Cessna is about what it's calibrated for then the error is going to be coming straight in but if we're going pretty fast and we're tilted down a little bit then it's still not going to be coming straight in does that make sense yeah so that's kind of that's what the the calibrated air speed is is used for so the calibrated AirSpeed is essentially your your Benchmark to prove that you're accurate at one AirSpeed and everything else is indicated what you're going to see is so for your indicated air speed like let's say your indicated air speed is um 55 knots but your calibrated air speed when you're is going to be 52 knots so you know when you're indicating 55 your actual air speed due to error is going to be 52 knots okay does that make sense yes so you yeah there's a chart you just see indicated air speed is this calibrated air speed is this so it's kind of a step process when you because indicated AirSpeed doesn't really tell us much as far as performance calibrated AirSpeed into it indicated AirSpeed is only good really for flying the airplane that's that's why you need to fly the airplane because it's the amount of air that's hitting the aircraft right right if you take the aircraft in a vacuum in in just the aircraft not moving and then you have the airflow going around it like you would in a wind tunnel that's what you you're basically measuring the amount of air that's hitting the airplane in the Wind Tunnel right in in the within the air mass in itself and that's what you need that's why um we look at different things like indicated AirSpeed and true AirSpeed and ground speed because they're all really different references so that indicated AirSpeed is important for flying the airplane that that's not going to change based on you know how high you are where you are that's that's what you use to fly the aircraft now calibrated AirSpeed is uh is an intermediate speed I like to call it it's something to get to the next thing which is your true AirSpeed now what is true AirSpeed it's your true speed it's the actual airspeed of the aircraft through the air mass yes through the air mass and that changes with what it's going to change with wins and it's going to change with non-standard temperature and pressure okay so that's your calibrated AirSpeed corrected for non-standard pressures and temperatures as you start to climb the thickness of the air changes performance of the aircraft change your true AirSpeed is going to change your indicated AirSpeed might remain the same you might still be flying at 100 knots but your true air speed is going to be different if you're flying at 100 knots indicated at sea level or 100 knots indicated at 18 000 feet that indicated AirSpeed is going to be the same the true AirSpeed is going to be different because of difference in pressure difference in temperature so you'll see in the aircraft in some aircraft um there's a little knob on the airspeed indicator especially on a six-pack that you can turn and in there you can set altitude and pressure and if you use an old school e6b how do you find your true AirSpeed by sitting pressure and temperature at an altitude and then you'll be able to convert your calibrated AirSpeed to your truer speed okay so and then the next one the last one is you ground speed now what is your ground speed that's your how fast you're driving essentially it's how fast you're traveling across the ground yeah in relationship to the ground as reference so you get that air mass and that air mass might be moving as well so if you if the air mass is not moving if there is no wind calibrated a true AirSpeed equals ground speed if that air mass is moving because of the wind then the ground the ground speed is going to be different right so what's the worst thing a headwind or tailwindness as far as as your ground speed to make it faster to make it to go faster to go faster what is what is what is the best thing to have Tailwind Tailwind Tailwind okay so it's going to push you around yeah the one way to remember it is iced tea iced tea into indicated calibrated well we didn't cover equivalent yeah which is something that in general aviation aircraft we're not really going to have to deal with too much but that's um that's really for higher performance aircraft and correct me if I'm wrong but what it is is it's air packing around the pitot tube what happens is that airplane's going so fast that not enough air can get into the pitot tube to there's a disturbance in the entrance there's a disturbance so the reading isn't quite accurate so it's iced tea and if you remember the previous one is corrected by the next one so indicated air speed is what's right out the dial calibrated air speed is indicated air speed for uh um installation and aircraft error um equivalent air speed is calibrated AirSpeed for compressibility error T true air speed is um equivalent air speed come um corrected for non-standard temperature and pressure ground speed is true air speed correction for wind yep so iced tea and then G STG so all these are very important all these air speeds are very important on your airspeed indicator there's a bunch of markings do you remember what the markings are the different colors um if I can look at the air indicator I do I think let me pull your one here I'm actually I went ahead because I'm in the altimeter already so the white let's start with the white the white is your um I believe it's a stall speed in a specific configuration the bottom of the bottom of it yep the white is um it's flaps it's flaps flaps yep flaps operating range um so the top of it is called what you remember so the bottom of it is called vs0 or we call it vso but it's vs0 really because some people say oh instead of zero yeah Tom get in trouble for saying ATC got mad at me because I said 402 Echo Romeo instead of four zero to echoromia so the airliners were doing it on referring saying 007 uh American you know and center but you know it's fine it's fine so vs0 vso um that's your stall speed in The Lending configuration hence because it's when you land you have flaps on right yes so that's the bottom of the white Arc is landing in the landing configuration that's your stall speed so it's easy to remember stay away from that give yourself a little bit of margin so you don't get to that point and then the top of the white Arc would be what you remember I don't VF e v f e flaps V slabs extended yep flaps extended so you cannot fly um any faster than that with the flaps extended or else what you'll damage your flaps you could damage the aircraft um okay then we have the green Arc what's the green Arc normal operating normal operating okay and then the bottom of the green Arc would be what the bottom of the green Arc would be your stall speed flaps up yep and so they call it in a specified configuration because I think it might be different for some aircraft yeah I think it's always called a specified configuration but typically it's yeah with with uh with no flaps and then the top of the the green Arc is what it's your it's your maximum cruising speed right it's the maximum cruising speed okay um and I don't remember what it stands for I don't even know if I ever knew what it stands for what the O stands for I don't remember normal operation maybe probably normal operation so the key here is what then we have the yellow Arc can you fly in the yellow Arc you can when as long as there's there's a caveat that's that's why as long as there's no turbulence as long as there's no turbulence because um if there's turbulence what could happen is that you can exceed the uh the structure you can exceed the G limits of the aircraft which would cause structural damage to the aircraft so in smoother you're fine but in that in that range you don't want to do a lot of g-forces on the aircraft because if you exceed the g-forces um then you you create issues with the aircraft in the green Arc what happens if you exceed the g-forces let's say you're flying with Tom and then you're flying in the green Arc and then Tom pulls really hard on the control what's gonna happen it's probably going to stall it it's going to stall yeah we're gonna enter an accelerate install it's going to stall and and that's the key between the two once and that's all in the VG diagram if you remember the VG diagram I think we look at it in the future chapters but that's exactly what happened so you got to be careful there and then at the end of the yellow Arc we have what the never exceed speed yeah which is the red line Viennese I remember that one yeah what if you exceed that uh your airplane could come apart yeah yeah so you can create structural failure so structural damage natural damage in the yellow structural failure above the yellow yep so you know we talked about this accident that happened in Pilates although we don't know exactly what happened but we had talked about possibly them exceeding well the aircraft fell apart right to get destroyed in Flight in the middle of a big storm so one of the potentiality is that they basically um exceeded the vne and then structural failure at that stage Wings fall apart and all that good stuff well bad stuff right um okay there's some air speeds that are not depicted on the uh on the airspeed indicator do you remember what if I say VA do you know what VA is no okay that's your Veterans Administration maneuvering speed you should know we dealt with them enough it's a maneuvering speed what's the maneuvering speed what does it mean that's this is it the minimum speed you would want to conduct Maneuvers at it's the no it's the maximum speed maximum speed you would want to conduct Maneuvers do you know why it's not charted why it's not listed on the airspeed indicator do you remember no because it changes with weight okay yeah it depends it depends on the weight then we have a few landing gear things you have vlo which is the operating speed at which you can operate the uh the gear so extending or retracting the gear in most aircraft it's the same as vle which is the landing gear extension speed the maximum speed at which you can extend so there's uh yeah some aircraft have two different speeds so you have to be careful you don't have to worry about that right now because that's not where you're gonna fly then there's vmc that I talk about in the course but we're going to skip that now there's two other speeds that are important on takeoff which which are VX and VY I think there's three speeds important on takeoff your vrs OVR yeah well of course yeah VR as well so let's start with VR because that's the first one what's VR you rotate speed rotation speed yep what is that it's when you start to pitch up to actually take off okay and why do we have that speed what what what information does it give us why do we care about that because your aircraft is going to want to take off early because of ground effect so you if you take off before your rotation speed you get stuck in ground effect where you're not actually going fast enough to get out of ground effect and so you're stuck yep that's when you want to start pulling on flight controls not too early especially when you had a high altitude I have a bad tendency to uh usually rotate a little too early here at a high altitude and then VX what's VX VX is your VX is best climb over a certain distance correct you're clearing an obstacle an angle of climb the best angle of climb yep and your VY is your best climb over time yes rate of time best rate of claim yep so angle because it's a distance rate because it's time time yeah and that's how you remember when do you use VX why do you need to clear something at the end of the runway yeah when you need to get off the ground quickly in a short distance there is a an obstacle at the end then you're going to do that uh why don't we use VX all the time because it's not your best for you to climb because it's not the best rate of flame so yeah over time you want to be able to get to a certain distance it's a bit more efficient to use VY okay there's a lot of reason there are several reasons for it first off very high pitch which means that you can't really see obstacles outside very high pitch means you're closer to your stall speed all speed which you know you'll get a bit more of a buffer with VY and in very high pitch means less airflow getting into the engine you cool it off right our engine is air cooled not liquid cooled so we need to be especially in the summer when you fly in the summer in the hot weather you probably know that better yeah we had problems with the archers getting right close to redline when we were just trying to get up to altitude because we're going to climb at 300 feet per minute wow that's uh Tom flies in In The Valley in Phoenix where it gets pretty darn hot in the summer too hot too too damn hot we have a saying but I'm not going to say it live on air for what Phoenix is I have a saying but it's not it's not YouTube safe um okay any additional questions on the airspeed indicator no I think it's uh I think it's covered pretty well okay um then the next instrument is your altimeter how does the altimeter work what does how does it work it reads the outside pressure and then um gives you an altitude based on whatever you set your Baseline to okay all right Baseline so tell me more about the Baseline what does what does what your Baseline is going to be your altimeter setting the alternate is setting okay now inside the instrument do you know what how it works what there is inside the instrument just a little wafer a little wafer yeah what's inside the wafer inside the wafer yeah the wafer sealed right there's air inside the wafer okay and what what kind of error is inside the wafer what kind of air I know where you're going it's a hard question to ask that's what I was trying to get to like kind of is what pressure of air sea level so it would be standard I I assume it's a standard day yeah it's 29.92 on the inside um but it's can't be standard because it's the temperature is so it's going to be 29.92 right yeah 29.92 so so what does the you said you can set you can set the pressure are you setting the pressure inside the wafer when you said that little window you're just you're calibrating you're calibrating where whether that whether your your pressure is above or below that 29.92 and you're yeah it's a calibration gear you're right it's it's a little knob that you twist and all you're doing is you're just changing the reference where the zero is located on your watch it's like saying you know having a manual watch you can set it to whatever you want so um so yeah you're just moving the gears it's a little lever that moves what's that window called I had a friend in college over his name his name was Coleman and so I always and it spelled differently but I always spell it that way for some reason because Coleman the Coleman window yeah um all right so what's it actually called the Cole's man k-o-l-l-s colesman window um so very much like what we have in the um in the airspeed indicator we have different types of altitudes do you remember what they are AGL and MSL okay well let's start with that let's get started with indicated altitude indeed yeah we'll get to that in a second but you start with MSL and AGL I think that's important what's the uh what's the difference between the two just your reference sea level versus surface sea level versus surface so MSL stands for mean sea level mean sea level okay and then AGL above ground level above ground level so which one does the airspeed indicator tell us the airspeed indicator the altitude the alternator [Music] uh the altimeter is gonna our references C Level so it's MSL MSL yep and why why is that why don't we want to know are we going to be flying over mountains here why don't we want to know the altitude above because it's changing quickly because it changes all the time and you want everybody on the same plane of the same reference plane yeah if I mean the ground isn't flat if you've got somebody who is over the mountains over here at you know 500 feet AGL and you're like oh I'm I'm fine I'm at 3 000 feet above where we are AGL you're on the same plane you're on the same plane same reference so when you say you're 3 000 feet and you say you had 3 000 feet in your airplane we're at the same altitude so yes because he could be 500 feet above the ground I could be a thousand feet above the ground that doesn't tell anything to anyone uh so when you take off at the airport is the altimeter going to show zero No it should show whatever your field elevation is unless unless you're at sea level there you go okay good but the reason I'm asking all these questions is because a lot of students get confused with that at first they if you haven't been in an airplane it's natural to feel like if the aircraft is on the runway you you might think oh I wanted to show zero because I'm going to be doing rounds in a pattern for example and no that's not how it works you need to have the airport elevation showing on your on your thing okay um what um I'm trying to think about the pressure that you're going to put in into your altimeter comes from where a Metar a Metar what else or whatever weather information you can get so if you go to controlled airport how would you know without looking at the Metar s theaters okay it is that automated report that you get on the radio if you go to an uncontrolled Airport there might not be a weather station or well and if there is what would it be called if there is yeah it would be awos or Asos or Asos okay good and then there's another way which you probably don't know because you haven't flown but uh the controller might tell you or would the person in charge of that block of airspace that you're in so when we fly to the Grand Canyon which we've done a couple times now um on the way there you talking to Center La Center Albuquerque Center whatever Center is in your area they are in charge of a larger block of airspace between airports and they'll tell you when you go from places to places altimeter reported at this area at this so then you just reset your altimeter that number that they give you is that the actual pressure at that airport let's say we go to Prescott today and the the pressure is reported at 29 let's say 29.92 is it because the pressure at five thousand feet in Prescott is 29 corrected for it being at sea level it's corrected for being at sea level you know the reason I'm asking this is because I did all my training in Florida in Florida is sea level everywhere and I not until several years after doing my training I got two airports that were way above sea level and and I and I started realizing that the pressure there was not really the pressure that was um reported so today if it's 29.92 inches of mercury reported in Prescott the actual pressure outside would be 24.92 24. roughly roughly five inches less one inch per thousand feet so that's important to to understand because what is your altimeter doing you put 29.92 in the altimeter window it's still referencing sea level it's still it's referencing sea level and it's reading the pressure outside which is 24.92 and it's giving your altitude MSL so on the runway it should be 50 45 I think five yeah five five thousand roughly five thousand feet right 5045 feet because of that pressure differential so that's the important part that that people don't understand is everything is always going to look like a pretty high number regardless of where you are okay um the we might just uh let me see here what's the alternator going to read if the static Port becomes blocked whatever air is stuck in there the static port yeah oh I'm sorry yeah yes yeah I was on the airspeed in the kitchen yeah the altimeter is going to read whatever air is stuck in there so you're you're going to be able to climb and descend and there's going to be no visual change on your altimeter yep okay how did you fix that uh land and unblock it there's a there's several different things you know um is there anything anywhere else in the aircraft that might give us a secondary reading I mean there may be a second sport equipped with a uh they call it an alternate static source and it's usually vented inside the cabin okay so like if you're outside static Port comes blocks you have one inside and you can hit the um you can turn it on and what it'll tend to do is actually read a little bit higher this kind of and it reads higher like at the private level you don't really need to have a thorough understanding of it but the reason why is the Venturi effect because the air the pressure outside is lower because it's moving the pressure inside's a little bit higher so it's going to be a little bit higher okay and then um you know if for some reason you do pick up icing you don't have to you know you gotta in a 172 you got to be very careful about staying out of icing conditions but in the event like you fly through a cloud or some visible moisture and your static Port becomes blocked and for whatever reason your alternate static Source isn't working you can actually climber descend to an area of warmer uh warmer weather and then it'll unfreeze and then it'll start working again so that's that's something to consider like in air yeah you can land but you really want that altimeter to be working um as you're coming into as you're coming in to land and so I've there's another method too if that static Port doesn't work that alternate static Port you know what you can do bust the vehicle so yeah bust the window of the instrument and the least useful of all three is the vsi so if you break the window of the vsi then it would use air from inside the cockpit to go to that instrument that becomes a static Port the instrument in itself becomes a static Port interest or an alternate stag Port that's Last Resort yeah in the case of a the pitostatic system the entire system all the instruments are sealed right so if you pop the glass on the they're all sealed and they're all on the vsi connected yes then you're introducing air from inside the cockpit into the into the system as a yeah like a makeshift static Port but yeah I wouldn't go around you know it's like oh something's not working because flight school is not going to be happy with you that's in case of urgency break the break the window break the glass uh there is this concept I talk about in the course which is always difficult to understand which is the the high to load Lookout below high to low Look Out Below so high pressure If you go from an area of high pressure to an area of low pressure and you don't change the altimeter setting appropriately what can happen your altimeter is going to read that you've remained in the same altitude while you've descended okay so you are closer to the ground yes then your alternator is telling you yes the ultimate is lying to you yep it's giving you it's giving you a false sense of security that's dangerous I too low Look Out Below right so high pressure to low pressure or high temperature to low temperature both of these and the reason is because high temperature inside of that altimeter it's like having a high temperature inside of a pressure cooker what happens when we have a pressure cooker and we close the lid or your tire in your car and they start to get hot then the pressure increases so that's the same thing as temperature increases pressure increases inside of that enclosed environment that's not always true in the atmosphere but inside the thing that's that is true so high to low Look Out Below so you got to be careful with that there's a lot of questions in the FAA database where they try to trick you because they ask you about your true altitude versus your indicated altitude so in this case what is the relationship between your true altitude and your indicated altitude your true altitude is your true altitude is higher or lower than your indicated altitude for high too low high to low your true altitude is going to be lower than your indicated true altitude is going to be lower than you indicated meaning you're in your altimeter is lying to you yes reverse statement you indicated altitude is higher or lower than your true altitude indicated altitude yeah is higher than your true value there you go there's a reason I'm I'm having you say this is because the fa Awards these questions to their friend whites sometimes they give you the true altitude as a reference sometimes they give you the indicated altitude as a reference and that gets students really really messed up so just just uh this is a tip for you that are watching just make sure that you do what Jason just did the the high too low your altimeter is lying this is dangerous then you have to think about I always kind of draw it on a piece of paper just to uh to make sure so and sometimes they'll tell you the other way around if you go from an area of low pressure to an area of high pressure that's the opposite then your altimeter is no it's lying but in a good way it's basically telling you that you're much lower than you actually are which means that you would be safe and you would just start climbing so okay there's we talked about true altitude we talked about indicated altitude what's absolute altitude you remember I I want to say that absolute altitude was your altitude above obstacles and it was just another AGL it's an egl yeah it's AGL so we don't use it very much in aviation because we don't have an instrument to tell us but in the perfect world in a perfect world if you set your altimeter correctly what is the relationship between indicated and true altitude are they the same are they higher are they lower should be the same it should be the same right in if you're flying right if you have your altimeter set correctly indicated equals true and then maybe we'll end this on this thought right here which is your pressure altitude and your density altitude what are those two terms pressure altitude is your altitude corrected for non-standard pressure the pressure altitude is your altitude corrected for non-certain pressure what does that mean uh it means that you have high and low pressure systems and so pressure changes across the Earth and you're not ever going to have that standard day does that mean that my altimeter is going to show different if I'm in Prescott at 5000 feet and the pressure altitude is six thousand feet what is my alternator it's a performance ah it's yeah it's not a altimeter oh okay performance okay um altitude it's a performance altitude it's an equivalent altitude essentially it's an equivalent altitude for performance purposes performance is the pressure altitude the one or is density altitude the one what's density altitude density altitude is pressure altitude corrected for non-standard temperature so we add another Factor now we can we we convert for we we pressure us food is the step it's density altitude is what we really care about because on those hot low pressure days we want to know what the equivalent altitude is that we're flying at so the fill in the blank the higher or lower the density altitude is the worse the performance higher the higher the density altitude the worse the performance when we have a high density altitude what kind of air density do we have low air density low air density that messes people up so much right this is actually a question we have on our part 107 test and people every once in a while come back and say oh this is incorrect high density altitude it's density altitude it should be one word it should be hyphenated yes it's it's a it's a type of altitude so that means that you're at a high altitude means that you have low air density in this case okay very good and then um so you're saying that if I if I'm in Prescott it's you're at 5 000 feet elevation and the density altitude is 8 000 feet why do I care because the airplane is going to perform as though it was at 8 000 feet even though you're at five very good yeah I like that answer sorry I didn't let you talk much that's okay I get excited about this topic any other questions for Jason let's go back to the altimeter so you're at an airport with no weather reporting uncontrolled you're on the ground how are you gonna figure out what your altimeter setting is going to be I'm going to use standard a and calculate it based on um the field elevation simpler simpler yeah I mean that's good idea but yes there's a simpler simpler so you're you're sitting in the airplane you're gonna pull out your e6b and start doing all those calculations why don't you just take your altimeter and just set it to field elevation and then read your altimeter setting from there yeah makes sense as long as you know field elevation but that you you can't calculate any of that unless you know field elevation so yeah that's that's how you do it and that's actually also how you verify the altimeter um when you when you're when you set your altimeter if it's reported 29.92 you put 29.92 what if the air Airfield is 5000 feet but your altimeter is showing 5500 feet is that right no no you did something wrong right so what's the limit what's the uh the amount of plus or minus 75 plus or minus 75 feet right so you have to make sure that you you also have to be careful because some airports that that airport elevation is picked at one spot at the airport it's called the ARP of Port reference point and some airports have slopes so you could be brasket yeah exactly you could be 10 feet 20 feet lower than that spot so you have to somewhat know if you live in Florida it's fine but if you live in other places it might it might become tricky so you might look at it and be like it's soft by quite a bit but then if you think about it yeah you might be 20 feet below right there so 75 feet is still quite a bit of a margin okay I think we're going to wrap it up you did good on this one um I think this is an area that you're a bit more familiar with and uh and then it's a bit more logical I think yeah I can I can work through a lot of it yeah instruments are pretty logical so all right thanks folks for watching and we'll see you next week for the second part of fly instruments we still have quite a few more to talk about foreign