This has helped me so much it was the only thing I was struggling on and you nailed it for me. Thank you. Seriously. You're a legend. 😂😂 Love the intro about stumbling in drunk on a Saturday night...lol fantastic!
I love your video. As a student pilot in the US, knowing that one hPa equals 30 feet (27, really) is invaluable. My one comment/correction is that in your last example, you would get a much better answer on your graduated computer if you took the ISA temp of -15°C, subtracted it from the standard temp of 15°C, and used 0 instead of -20. Other than that little thing, I thought your video was wonderfully helpful. Cheers!
In the last example, you should be using 7,660' instead of 10,660' to find the true height (AGL), and then add that back to the surface elevation. We are trying to correct for the temperature of the column of air above ground, not all the way to sea level. If you do it this way you would get an answer much closer to the 10,200' you expected.
Example 3 - on the CRP-5, Answer comes out between 10000 and 10100, which is the Answer you would get using ‘10’ in the T.E.C. Equation instead of ‘7.66’… (10660-600) 😉
Please, I have a question about this "A flight is planned at FL180 over Mont Blanc (elevation 15782ft). The MSL is 983hPa, from an aerodrome at MSL, and the temperature of the air up to the summit is 25 degrees C colder than ISA. Determine the true altitude of the aircraft at Mont Blanc and hence the terrain clearence". What is the height correction for the temperature deviation from ISA?
In an ISA atmosphere, the temperature at sea level is 15deg C. The international temperature lapse rate is defined as cooling at 2 degreees per 1,000ft as you climb away from sea level. So in the first example what should the temperature at 16,000ft be? 16 x 2 = 32. So the temperature at 16,000ft should be 32 degrees below 15 deg C (15 - 32 = -17 deg C). However we have been told in the question that the actual temperature is -30deg C, so the deviation from ISA is -13 deg C. Hope that helps.
Thank you very much yes it helps to understand all the calculation behind, I am doing my PPL and we just did this is class but it was not so clear to me, and it is easy to get lost at home when making exercise... now all is clear, Thanks for your time and help.
In the last question, in CRP-5, in the aviationexam database there is an answer of 10,000ft so your method would be insufficient. I'm not sure what the method would be to calculate it correctly on the CRP-5, however; inputting -15 instead of -20 (therefore treating the ISA deviation as the actual temperature) seems to give the correct answer of approximately 10200, although this is most likely coincidental.
That's awesome, thanks a lot!! You did a small mistake on ex 3 when you put your dates in the flight computer. On presure altitude you should select the Alt of 7660' with -15° and you should read at 10,660 and the answer is 10,200 with no errors 😉
@@Goproflying Hi! Thanks for these videos, they help a lot! How to use the computer first, but as well to understand relations between all theses notions. Well, I have same question as David : Why do you calculate the station elevation based on QNH and not on the mean Sea Level, ie 1013hPa? When giving an elevation, for example on aeronautical maps, are we talkung about AMSL or QNH? I got lost at that point of your explanation... Thanks for your help!
ISA deviation is the actual temperature above or below what you would expect to find at that level. The question tells us the temperature is ISA -15deg (15deg below ISA). The equation requires us to use ISA deviation, so we just place -15deg in the box.
Hi everyone. Can anyone help me in finding the software for CRP5 (or relevant flight computer besides E6B)? I need to use it for my teaching class here in Malaysia. Thank you for your help. Cheers
I have been flying for many years and never calculated true altitude ..not necessary.Just use area QNH. Look it up on line or ask ATC or ground weather station report. All other aircraft in the same area are also using area QNH so all aircraft are showing same height on their altimeters. True altitude is used mainly for exam purposes.
In the last question, I dont understand why you took 7,66 in the Temperature Correction component of the equation instead of taking it 10,66. Just why?
Because there is only 7,660ft of air between you and the ground, not 10,660. You cannot do a temperature correction on "air" that is below ground level.
@@Goproflying 7660ft ... it's a little bit confusing. I understand that temperature is decreasing with 2 degrees on 1000 ft. Why you calculate 7066 in stead of 7000 ft? Can you help me with that? And the other thing ... here in Sweden we learn to calculate 27 ft for 1 hPa difference. Another confusing thing that not make the life easier at all ...
@@mrnick40 The 2 degrees per 1,000ft is not important in this question as you've already been given the ISA deviation. Normally using 2 Deg per 1,000ft is only useful if you need to calculate your own ISA deviation. Secondly, you are correct. For the EASA exams (at least back when I taught them) gernally we used 30ft per hPa for Meteorology, Operational procedures and Rnav, but 27ft for General Navigation. However, given the spread of answers, it doesn't make any difference in what's calculated.
The International Stardard Atmosphere temperature lapse rate is 2deg C per thousand feet. The International Standard Atmosphere temperature at Sea Level is 15 deg C. To calculate th ISA DEV at a given altitude. Take the Altitude in thousands of feet and double it. Subtract this number from 15. This is the temperature you would expect to find at such an altitude. The difference between this value and the actual temperature is the ISA DEVIATION.
![QNH, QFE and QNE - [Altitude, Height and Flight Levels explained]](/img/n.gif)
All your video are so easy to follow thank you for all these video I think i will be watch all these video Mate
This has helped me so much it was the only thing I was struggling on and you nailed it for me. Thank you. Seriously. You're a legend. 😂😂 Love the intro about stumbling in drunk on a Saturday night...lol fantastic!
Helped me nail my ATPL Nav exam. Cheers from Aussie
This is a really good explanation and three good worked examples...
I love your video. As a student pilot in the US, knowing that one hPa equals 30 feet (27, really) is invaluable. My one comment/correction is that in your last example, you would get a much better answer on your graduated computer if you took the ISA temp of -15°C, subtracted it from the standard temp of 15°C, and used 0 instead of -20. Other than that little thing, I thought your video was wonderfully helpful. Cheers!
In the last example, you should be using 7,660' instead of 10,660' to find the true height (AGL), and then add that back to the surface elevation. We are trying to correct for the temperature of the column of air above ground, not all the way to sea level. If you do it this way you would get an answer much closer to the 10,200' you expected.
True. Especially there is opposite to that what is said in video. Answers are NOT so clear, the closest one to CRP result is 10000ft and it is wrong.
Thank you for taking the time to explain this. Well done helped my a lot
really good explanation and examples, thanks
Awesome, very clear explanations!
Great video! Really nice explanation !
Really helped understanding True altitude
Hi man - just found your videos and am really enjoying them. What's going on with you these days? You working for an airline?
Example 3 - on the CRP-5, Answer comes out between 10000 and 10100, which is the Answer you would get using ‘10’ in the T.E.C. Equation instead of ‘7.66’… (10660-600) 😉
Excellent video! Very informative and easy to learn. Back to drinking.
Please, I have a question about this "A flight is planned at FL180 over Mont Blanc (elevation 15782ft). The MSL is 983hPa, from an aerodrome at MSL, and the temperature of the air up to the summit is 25 degrees C colder than ISA. Determine the true altitude of the aircraft at Mont Blanc and hence the terrain clearence". What is the height correction for the temperature deviation from ISA?
So in the last example, when using the CRP5, we can just ignore the terrain elevation altogether?
Thnks for the vids, amazing stuff! - May i ask where you use the CRP-5 virtually ? would really be helpful for my studies. Thanks again
sorry could you explain how do you get -17 and -13 as well please ? thanks a lot
In an ISA atmosphere, the temperature at sea level is 15deg C. The international temperature lapse rate is defined as cooling at 2 degreees per 1,000ft as you climb away from sea level. So in the first example what should the temperature at 16,000ft be? 16 x 2 = 32. So the temperature at 16,000ft should be 32 degrees below 15 deg C (15 - 32 = -17 deg C). However we have been told in the question that the actual temperature is -30deg C, so the deviation from ISA is -13 deg C.
Hope that helps.
Thank you very much yes it helps to understand all the calculation behind, I am doing my PPL and we just did this is class but it was not so clear to me, and it is easy to get lost at home when making exercise... now all is clear, Thanks for your time and help.
No worries, feel free to ask as many questions as you wish.
Fantastic video, thank you!!
In the last question, in CRP-5, in the aviationexam database there is an answer of 10,000ft so your method would be insufficient. I'm not sure what the method would be to calculate it correctly on the CRP-5, however; inputting -15 instead of -20 (therefore treating the ISA deviation as the actual temperature) seems to give the correct answer of approximately 10200, although this is most likely coincidental.
Any scope for some ATPL stuff? :)
Excelent Explanation. Thank you very much!!
Excellent stuff!
Is *ALT in the TEC equation technically the AGL? Would it be wrong to say that?
If you're flying over land, then yes it's AGL. If you're flying over open water then it's AMSL.
That's awesome, thanks a lot!! You did a small mistake on ex 3 when you put your dates in the flight computer. On presure altitude you should select the Alt of 7660' with -15° and you should read at 10,660 and the answer is 10,200 with no errors 😉
You must have a better CRP5 than me :) I've tried a few different attemps and get the same answer every time. Thanks anyway
how to download CPR5 for a laptop or a PC ........... Thanks
Amazing
Hi, Very good explanation.The station elevation is at 3000 ft,shouldn't it be measured from sea level and not qnh?
Uziel David qnh is sea level
@@Goproflying Hi! Thanks for these videos, they help a lot! How to use the computer first, but as well to understand relations between all theses notions.
Well, I have same question as David : Why do you calculate the station elevation based on QNH and not on the mean Sea Level, ie 1013hPa?
When giving an elevation, for example on aeronautical maps, are we talkung about AMSL or QNH? I got lost at that point of your explanation... Thanks for your help!
The last example,you made a mistake in the temperature. You set it -20, but it was -15, so it gave you a lower altitude by 150.
In the last example it was just given ISA -15 °C then how come we took it as ISA Dev. Can u please tell me that?
ISA deviation is the actual temperature above or below what you would expect to find at that level. The question tells us the temperature is ISA -15deg (15deg below ISA). The equation requires us to use ISA deviation, so we just place -15deg in the box.
@@Goproflying Thankew! Got That👍 Please do carry on with these vids , they're helping us alot! (Just try to avoid direct steps😓)
@@Abrarsiddique0119There is a plan to continue with the CRP-5 vids, just need a bit of time. Stay tuned
thanks bro it was really helpful
THANKS!!! You just saved me 🙂
nice explained
How you got -17^c on FL160? It shouldn’t be 2*16=32^?
15-2*16 = -17
Hi everyone. Can anyone help me in finding the software for CRP5 (or relevant flight computer besides E6B)? I need to use it for my teaching class here in Malaysia. Thank you for your help. Cheers
I have been flying for many years and never calculated true altitude ..not necessary.Just use area QNH. Look it up on line or ask ATC or ground weather station report. All other aircraft in the same area are also using area QNH so all aircraft are showing same height on their altimeters. True altitude is used mainly for exam purposes.
Totally agree. This tutorial is only for those struggling with Gen Nav/Met ATPL.
In the last question, I dont understand why you took 7,66 in the Temperature Correction component of the equation instead of taking it 10,66. Just why?
Because there is only 7,660ft of air between you and the ground, not 10,660. You cannot do a temperature correction on "air" that is below ground level.
Gotcha! Thanks a lot.
@@Goproflying 7660ft ... it's a little bit confusing. I understand that temperature is decreasing with 2 degrees on 1000 ft. Why you calculate 7066 in stead of 7000 ft? Can you help me with that? And the other thing ... here in Sweden we learn to calculate 27 ft for 1 hPa difference. Another confusing thing that not make the life easier at all ...
@@mrnick40 The 2 degrees per 1,000ft is not important in this question as you've already been given the ISA deviation. Normally using 2 Deg per 1,000ft is only useful if you need to calculate your own ISA deviation.
Secondly, you are correct. For the EASA exams (at least back when I taught them) gernally we used 30ft per hPa for Meteorology, Operational procedures and Rnav, but 27ft for General Navigation. However, given the spread of answers, it doesn't make any difference in what's calculated.
@@Goproflying Thank you for the clarification ... I missed somehow that ISA deviation was already in the equation
at min 15:45 true alt is 15180 ft not 15090
thanks
How to calculate the temperature at isa dv
The International Stardard Atmosphere temperature lapse rate is 2deg C per thousand feet.
The International Standard Atmosphere temperature at Sea Level is 15 deg C.
To calculate th ISA DEV at a given altitude. Take the Altitude in thousands of feet and double it. Subtract this number from 15. This is the temperature you would expect to find at such an altitude. The difference between this value and the actual temperature is the ISA DEVIATION.
great !!
thank
QNH is not the pressure level at sea level.
Correct, it is the pressure setting required to determine the aircraft elevation at an aerodrome, with respect to mean sea level.
The real bummer is that there is also 10 000 ft answer possible in that (last) question (↼_↼)
Can I have your email or something