today we will talk about the wind triangle a wind triangle is a graphical representation of how the wind affects an aircraft in flight and it helps to determine relevant values for navigation such as wind correction angle and ground speed now this triangle is composed of the following segments true course in ground speed wind direction and speed and true heading and true air speed however the way the triangle is constructed may vary slightly so before we get into how to construct it let's see the logic behind the wind triangle for instance let's look at this example of a boat trying to cross a river from point a to point b let's say there is no current in this case assuming that point b is exactly north of point a the boat should sail with heading zero degrees and since there is no current there will be no drift and therefore the track will be zero degrees as well now let's analyze the same situation but now with a current of five knots flowing from left to right in relation to the desired course in this case if the boat sails with a north heading the current will deviate the boat to the right now this 5 knot current implies that after one hour it will push the boat five nautical miles off course this means that after 30 minutes the boat will be 2.5 miles off course and after 60 minutes it will be 5 miles off course now if we analyze this situation we can see that there is a triangle which can be used to determine the drift angle which in this case is 5 degrees therefore under these conditions with a north heading the actual track will be zero zero five the same principle applies to an aircraft in flight let's say for example that an aircraft wants to fly from point a to point b with a desired course of zero niner zero degrees if there is no wind there will be no drift so the track will be zero niner zero as well however if there is a five knot crosswind flowing from left to right in relation to the desired course it will push the aircraft off course this way after 30 minutes of flight the aircraft would be 2.5 miles off course and after 60 minutes it will be five miles off course and here again we can use this triangle to determine the drift angle of five degrees which at the same time can be used to determine the actual track of the aircraft which would be zero nine or five with this we can see that constructing a wind triangle is a useful way to solve wind problems graphically using geometry however we have to say that there are two main ways in which we can construct this triangle for this video we will refer to them as method a and method b with the method a given a certain heading true airspeed and wind we can determine the drift angle the track and the ground speed while with method b given a desired course or track true airspeed and wind we can determine the wind correction angle the corrected heading to be flown and the ground speed in both cases the theoretical background is the same but the way the triangle is constructed is slightly different so using method a or b will depend on the kind of problem we are trying to solve with this in mind let's begin with method a here the first step is to take a piece of paper and draw a straight line that represents the aircraft's heading in relation to true north the length of this segment must be equivalent to the true air speed so let's say for example that the true heading is 0 8 1 and the true air speed is 110 knots then we draw a line that represents heading 0 8 one as we can see here then for the length we can assume for example a scale of one not equal to one millimeter therefore in this case the length of this segment should be one hundred and ten millimeters having done this the second step is to draw a line that represents the wind direction and speed starting at the end of the heading true airspeed line that we draw previously so let's say for example that the reported wind is 0 3 0 degrees at 20 knots in this case instinctively we could draw a line like this however this is not correct since wind direction is always reported as the direction from which the wind blows and to build the triangle we are interested in drawing the direction in which it goes because that will be the direction in which it will push the aircraft so then in this case using 0 3 0 as reference we draw a line in the opposite direction with a length of 20 millimeters as we can see in this example then after doing this the third step is to complete the triangle by drawing a straight line that joins these segments as we can see here the length of this last segment will be equivalent to the expected ground speed which in this case is 100 knots and the angle between this segment and the heading true airspeed segment will be the drift angle which in this case is nine degrees with this information we can determine that the actual track of the aircraft would be zero niner zero now in practical terms what this triangle is telling us is that with a wind of 030 degrees at 20 knots an aircraft flying with a heading of 081 and a true airspeed of 110 knots will actually be flying with a track of zero niner zero degrees and a ground speed of 100 knots here we can see a summary of the different segments and components of this triangle constructed using the method a now let's have a look at method b here the first step is to draw a long straight line that represents the desired true course of the route in this example let's say the desired course or track is zero niner zero so we draw a line like this as a side note here the length of this segment does not matter for now we will see later why so having done this the second step is to draw a line that represents the wind direction and speed but here unlike with the other triangle we will draw this line starting from the tail of the true course line that we draw previously so let's say that the reported wind is 0 3 0 degrees at 20 knots in this case just like in the previous triangle we cannot draw a line with heading 0 3 0 because we are interested in representing the direction in which the wind is blowing which in this case would be 2 1 0. and assuming in scale of one not equal to one millimeter the length of this segment should be twenty millimeters then after doing this we draw a line starting from the head of the wind segment with a length that represents the true air speed to intercept the true course line in this example let's say the true air speed is 110 knots so then the length of this last segment must be and ten millimeters in such a way that it intercepts the true course line of zero nine or zero now with the triangle already constructed we measure the resulting length of the true coarse segment which will be equivalent to the ground speed in this example the length is 100 millimeters so the resulting ground speed would be 100 knots now with this triangle we can measure the angle between the heading true airspeed segment and the true course ground speed segment to determine the wind correction angle which in this case is 9 degrees however if we analyze the direction of these lines we can see that actually the correction angle would be negative thus obtaining minus nine degrees as a result now knowing the wind correction angle and the true course we can determine the resulting true heading which would be zero eight one so basically what this triangle is telling us is that if we want to fly on a desired true course of zero nine or zero degrees with a true air speed of one hundred and ten knots and a wind of zero three zero at 20 knots we would have to fly with a true heading of zero eight one and we would get a ground speed of 100 knots here we can see a summary of the triangle constructed according to method b so with this we can see that although the results of both methods are practically the same the focus used is different so using method a or method b will depend on the type of problem we want to solve now finally wind forecasts may not be accurately met or conditions may change suddenly during flight so it is important to identify any deviation from the intended track and correct it for example in vfr flights we can use visual references along the route to return to the desired track and we must be aware that if there is any change in the headwind or tailwind component the flight time will be affected as well now in case of ifr flights we have to use the navigation instruments such as a cdi to identify any deviation and correct it a useful method to determine quickly the drift angle and therefore calculate the required corrected heading is the one in 60 rule which we will discuss in detail in the next video i hope the information presented in this video was useful if so don't forget to share like subscribe and leave a comment down below thanks for watching [Music]