class b regulations allow us to safely fly small propeller-driven aircraft during the night and during bad weather but what sort of restrictions and rules surround Class B aircraft let's find out hi I'm Grant and welcome to class 12 in the performance Series today we're going to be taking a look at class b regulations these are basically a list of rules and performance targets that we need to achieve in order to fly a Class B aircraft during bad weather and at night time so it vastly opens up what we can do with our small propeller driven aircraft if you haven't done so I'd recommend going back and watching all the videos up until this point as well as maybe trying the study session I did in the previous class to get a good understanding of the fundamentals because you will need those fundamentals to understand really what's going on with all these rules and regulations so let us remind ourselves of what a Class B aircraft is first of all a Class B aircraft is small less than 5 700 kilograms maximum takeoff mass and it's also an aircraft with nine or fewer passenger seats it has to be propeller driven and that propeller can be stuck on the front of a piston engine or a jet engine to make a small turbo prop a Class B aircraft can be single engine or multi-engine although with a single engine Class B aircraft their use is restricted legally and a single engine Class B aircraft cannot be used for public transport operations at night or in IMC instrument meteorological conditions which essentially means bad weather this basically severely limits the scope of what a single engine Class B aircraft can do if a multi-engine propeller aircraft can't meet the class B performance regulations that we're going to look at in this class then it would default to be treating like a single engine aircraft and you would only be able to use it during the day and during good weather the class B performance regulations basically said conditions that operators of the aircraft Airlines really have to follow in order to safely and legally fly these aircraft it's like a list of requirements that we would have to satisfy in order to be able to fly in and out of that aircraft at that airport in that aircraft on that day the first thing we do is we need to take off and the regulations to find some things that we need to achieve the first of these is that we must take off below the maximum structural takeoff mass of the aircraft which seems pretty obvious to me the main thing we need to consider with takeoff is really the runway characteristics remember the takeoff distance available accelerate stop distance available and take off run available including the runway stop we clear away that kind of thing so basically if we have no stop way or clear way the takeoff distance that we require multiplied by 1.25 must be less than the takeoff run available so imagine there's nothing there we have to take off in uh our takeoff distance times 1.25 must be less than this total distance here if we have a stop way or a clear weight then we need to make the take the most restrictive of these three values so the takeoff distance required must be less than the takeoff run available that's this portion here the actual ground of the runway the takeoff doesn't require times 1.15 must be less than or equal to the takeoff distance available so including the clear way and the takeoff distance required multiplied by 1.3 must be less than or equal to the accelerated stop distance available so the runway and the stop way so we take the most restrictive of that and we also apply some other factors to it depending on the runway surface so if we're on a normal paved Runway it is fine uh even if it is wet but for a grass Runway we multiply The Distance by 1.2 that would be our takeoff distance required Times by 1.2 and then we would apply these next factors and if it's wet grass it's 1.3 once we've accounted for the surface we need to think about the slope of the runway and for every one percent of upslope we must increase the takeoff distance required by five percent up to a maximum upslope of two percent for times though we don't calculate the advantage that it would give us so that we don't overuse the downslope in our takeoff distance required calculations this is similar to what we do with wind if you remember we only consider 50 of the headwind component so that we aren't being helped too much by it and we take 150 of the Tailwind so we are over compensating for it this is something you're going to see a lot in these regulations and the class A regulations we consider the things that would be negative for our performance so we can correct for them but we don't necessarily consider the things that would be beneficial for a performance so that we're always on the safer side of things we're more conservative than we need to be so the process for finding out if we comply with our class b regulations for takeoff would be we would calculate our takeoff distance required using our graphs or like a calculator app is what we actually use in the airlines we apply the slope and the surface factors then we multiply by 1.3 and make sure it's less than the accelerated stop distance variable we also multiply that value by 1.15 make sure it's less than the takeoff distance available and we also check it again to take off run available and we use the most restricted value basically what you can also do is you can divide the takeoff distance available by 1.15 on our takeoff distance required would not be allowed to exceed that value and you would divide the accelerate stop Distance by 1.3 and our take a distance required would not be allowed to exceed that value that's what you actually do when you're using the graphs in the exams so after takeoff we have the initial client phase where we have some assumptions made about how we are climbing with both engines operating so we basically have takeoff power set on both engines we're achieving at least a four percent client gradient the flats in the takeoff position that our speed is 1.2 VS1 or 1.1 vmc whichever is the higher of the two and the landing gear is retracted if it can be within seven seconds if one of our engines fails on takeoff at 400 feet above the surface the twin engine aircraft must be able to achieve a measurable positive gradient of climb up to 1500 feet this assumes the critical engine has failed with the remaining engine still at takeoff power we put our positive climb gradient at least anything positive the flats remain in the takeoff position we have the same speed as we did at passing the screen height so it would still be 1.2 VS1 or 1.1 vmc and the landing gear is now retracted we continue this climb up to 1500 feet where we can reduce the client gradient to 0.75 percent this assumes that the critical engine remains failed but the continuous engine has been reduced to maximum continuous Source this is basically our instead of maxing out the engine we reduce the power a little bit so the engine where is less and it can last for longer we've got a 0.75 client gradient the flaps at this point will now be retracted reducing our drag which means that instead of being measuratively measurably positive it now has to go up to 0.75 got a bit less drag the speed increases a bit so it's 1.2 VS1 and the landing gear is retracted so this is the single engine and all engine requirements to fly a Class B aircraft at an airport if we couldn't achieve these profiles then we would not be able to operate as a Class B aircraft meaning no IMC no bad weather and no night flights and this is the case for an initial climate year somewhere where it's relatively flat it's our base level if they're mountains then we need to consider obstacle clearance and that means we may need to be able to achieve even better climb gradients than this so if we want to fly a multi-engine aircraft in bad weather or at night using the class b regulations we need to clear all obstacles that are in the way by a vertical margin of 50 feet obstacles are considered in the way are if they are within a Zone called the departure sector the departure sector extends out from the end of the clearway or the end of the runway if there is no clearway in a sort of a fan shape the exact dimensions look like this we've got 60 meters plus half the wingspan for a straight period and then the extending hour period would be 0.125 times the distance from the 0.0 point being the end of the clear way or the end of the runway and we generally refer to these things in terms of their semi-width or their half width and the equation for that would be 60 meters plus the wingspan over two the half wingspan plus 0.15 d and we continue this out until we reach a maximum half width of 300 meters if we have nav AIDS available or have visual references to departure and 600 meters either side if we have no AIDS say we have an obstacle in the sector that we cannot clear by 50 feet with our current weight this means that we would have to reduce our takeoff Mass so we achieve a better climb angle and can now clear it another way around this would be if the airport has a specific departure we can follow where the departure immediately turns we have to be above 15 feet and the bank angle has to be less than 15 degrees so it can't be like a full brutal turn it has to be just a sort of slight turn um and this would then remove the departure sector so the obstacle we couldn't clear now Falls outside imagine this fan instead of looking this way rotates a little bit and the obstacle that was here is now outside of that uh departure sector if we use this method for the turn for the departure then we have to widen the departure sector out to a maximum of 600 meters and then 900 meters if we don't have any navades available so it does help a little bit but we do have to consider a wider area because we are turning so if we do have obstacles in that departure sector we need to climb safely and clear all obstacles within that sector by 50 feet now we need to figure out a minimum angle or a minimum gradient that we would need to achieve in order to do this safely and that is what we were doing with the development of a net takeoff flight path in this example here we have this obstacle this mountain on its own that we would need to clear by 50 feet we then take a line from 50 feet above that obstacle to the end of our takeoff distance required our screen height and we have our minimum client gradient that we would need to achieve if we have two engines or if an engine fails we continue this line all the way up to 1500 feet above the ground but the way it looks could change depending on the cloud base but before we talk about that though we need to talk about our initial climb gradient so this line connecting the two 50 feet above points is constructed at a 0.77 the all climb all engine climb gradient sorry which takes a while to get your head around and I find it quite difficult so take your time look up other information if you need to but basically what it means is if we had all engines running with a certain takeoff mass and we're able to achieve a client gradient of maybe let's call this 10 for nice maths then 0.77 would be 7.7 climb gradient and that line of 7.7 percent climb gradient would have to clear all obstacles by 50 feet as we go up if we change our weight and increase the mass which remember would make our climb angle shallower then we're only going to achieve a climb volume for example of five percent then if we take 0.77 of that gradient we get a gradient of about 3.8 percent and if we draw a line of 3.8 percent we might not be able to clear the obstacles by 50 feet or we might indeed hit the obstacles which would mean we're too heavy so we would have to reduce the weight back down increasing our angle again so that our all engine angle so that when we take 77 of that angle we achieve this line at least and we can climb clearing all obstacles by 50 feet hopefully you follow that so far so for too heavy we might need to reduce our weight back down in order to achieve a 100 Cloud gradient that's steep enough so that the 77 climb gradient clears all the obstacles by 50 feet so that 0.77 times all engine climb gradient line will continue up to 1500 feet above the ground if we have a cloud base that is above 1500 feet if the cloud base is below 1500 feet like here for example then an allowance is made for an engine failure occurring when we enter the clouds so with a single engine we have reduced client performance and we can also no longer see the obstacles ahead of us we still climb up to the bottom of the cloud at this 0.77 percent all sorry 0.77 times the all engine climb gradient line but on reaching the cloud base we make the line less Steep and is based off of the gross single engine client gradient for that aircraft again if this line was to come closer than 50 feet within an obstacle within the departure sector then we would need to reduce our weight so that our single engine climb gradient would be sufficient again and also so that our initial two engine climb grading could be steep enough maybe we entered the clouds a bit earlier here and that shallow line is sufficient to clear the obstacles by 50 feet a little while to get your head around read some textbooks answer some questions take it nice and slow just think about it 100 it's nice and steep 77 still needs to be able to con clear everything by 50 feet and your weight has to change to allow that to happen most of the regulations for class B aircraft revolve around the takeoff and the landing so during the cruise phase there aren't that many and I think they're all quite logical and reasonable so the first one is the operator must ensure that the whole flight can take place above any relative safely altitudes along the length of the flight uh all the way down to a point a thousand feet above the destination eardrum taking into account any weather on Route basically you must be able to keep above all safety altitudes that might be on route the second one the aircraft must not climb to an altitude above the altitude where the maximum rate of climb of the aircraft is 300 feet per minute we don't want to get near to the point of simultaneous high and low speed stall or coffin corner if you have a quick look on Google you'll understand what I'm talking about or I do have a video in the principles of flight talking about coffin corner the next one is if an engine fails The Descent or climb gradients with one engine shall be the normal all engine gradients with a 0.5 percent extra safety margin for the gradient not the angle basically what it's saying is that if we have an engine failure and need to descend our new descend angle would be a bit steeper because we don't have the thrust available to control our rate or angle of descent as much so we have to assume we're going to be descending faster and steeper so we don't make any plans that we can achieve we can't get out of a mountainous region or something like that basically you fly above safe altitudes not too high that you can't that you reach coffin corner and in case of an engine failure make sure you can still clear all the obstacles if you need to in The Descent Landing has a few regulations but nothing too complicated the first and most straightforward one is that we must land with a weight that is below the maximum structural Landing Mass so we don't break the plane then we have to land within 70 of the planned Runway available taking to account which runways are open which one's most likely to be used for example so you can either take the total Landing distance available and multiply it by 0.7 to get 70 and compare that with your calculated Landing distance or you can calculate your Landing distance multiplied by 1.43 and that's the new distance which must not be more than the landing distance available this Landing distance has to be calculated with some certain assumptions as well the aircraft must cross the Threshold at 50 feet or as low as 35 feet if approved by the regulator in order to allow for a shorter Landing distance in uh tight aircraft tight airports basically where the runway is short at the altitude of the Landing Runway must be considered basically it means you've got to account for density changes that's what we looked at in the class on Landing density changes all these distances and the surface and condition and slope characteristics of the runway must be considered as well so I talked about these in the landing video we basically have grass runways we multiply The Distance by 1.15 and any weight runways we multiplied by 1.15 as well and take note that these are different from the considerations on takeoff and if for example we had a wet grass Runway we would multiply by 1.15 for the grass and then again for the wet Runway we also have to consider the slope just like we did for takeoff but remember that downslope is bad for landing because we're going to get pooled down the slope it's going to increase the landing distance so it's five percent increase per one percent of down slope on Landing not up slope like it is on takeoff and also we do the same thing that we do with wind all the time headwind only 50 percent and Tailwind 150 must be used in the calculation to get account for it and not rely on it too much in the case of Tailwind if for some reason we have to go around whether through meteorological conditions pilot error controller error basically there's loads of reasons to go around then we need to ensure we climb steep enough to clear any obstacles just as we did for the initial climb um and basically if we have both engines operating we need to achieve Agora and gradient of at least 2.5 percent with the Lander gear extended the flat still in the liner position and the speed at V ref which is the landing speed obviously if we have an engine failure then we need to achieve a gradient of at least 0.75 percent when 1500 foot above the runway with the landing gear now retracted the flaps now retracted and a speed of 1.2 VS1 basically we need to climb away fast enough so I'm going to summarize using the cap 698 document to show you how good a document this is to have in the exam if you're stuck when I sat my etls I found performance quite a difficult subject to wrap my head around and in the exam this document really helps if you don't remember everything you don't necessarily need to memorize all the factors and specifics you just need to be familiar with this document and know how to look up the relative Parts quickly so in class B we have the option of the single engine piston and the multi-engine Piston which I've got in the one document here I've left the class A stuff in a separate printout but if we have a quick look at the SCP stuff single engine piston so if I lift that up you should be able to see them so if you see the general requirements it says the operator shall not operate the single engine airplane at night in instrument meteorological conditions except when under special visual flight rules unless surfaces are available which permits safe Force Lander to be executed and above a cloud layer that extends below the relative minimum safality that's what we started off with we said single engine aircraft can be used in IMC or at night so it restricts their their applications in terms of commercial transport so instead of looking at the single engine stuff let's look at the multi-engine stuff so the multi-engine stuff for the general requirements we can see that it tells us it's propeller driven aircraft having nine or less passenger seats and a maximum takeoff weight 5 700 kilograms or less performance accountability for engine failure on a multi-engineer air airplane in this class need not be considered below a height of 300 feet so it's a bit more detail than I've given which is why it's such a good document it's got all the specifics should you need it and now if we think of those takeoff regulations we can see the requirements at the bottom of the page written out in plain English so remember at the very start of the video when we're talking about the comparisons for a takeoff distance requirement versus what is available we can see that if there's no stopware clearway the available takeoff distance when multiplied by 1.25 must not exceed the takeoff run available then if we do have a stop way or a clear way which must not exceed the Torah we multiplied by 1.3 not exactly Asda by 1.15 not exceed the total that's all those regulation factors I was talking at the front of the class I'm talking at the front of the class talking at the start of the class if we go over the page the way to calculate all these distances is given as well we can see that down at the bottom there's a oh it says distance calculation it gives you an example of all these things all these um stuff that you get figures from the graph says graphical distance we apply any surface Factor slope factors take off distance uh raw then you calculate your regulatory factor and you find out your takeoff distance is this way so then we go to the climb regulations for example so in the climb regulations here we can see our Optical accountability area we've got this semi-width at the end of the takeoff distance available 60 meters plus half the wingspan then we add on 0.125 times D it's all in here it's all in here and that initial climb that we have to assume four percent and then at 400 feet measurably positive and then at 1500 feet 0.75 there's also a few nice little calculations in here and this is talking about the optical accountability area if you turn going out to 300 600 or 900 meters depending on what you're doing yeah the graphs themselves there's a lot of details in these which I'm going to cover in the next class well not that much details but basically you get a value from the graph you apply any factors and that will work into the answer for the question and basically what I'm trying to say is that if you're a bit stuck get out the cap 698 and it should hopefully help a bit because there's lots of information in here should you feel stuck foreign