As you note, the numbers are scary at first, but once you know what they mean, it isn’t so bad. Thanks for the comment! I’m glad the video was helpful!
I like your video. Good explanations. However, I would have preferred to see units used in all graphics and formulas. Finally, I think density altitude is more relevant than pressure altitude regarding aircraft performance evaluation. Pressure altitude can be used in SOME POH; those with temperature correction as in Cessna 172N POH but not for the Beechcraft Sundowner C23 POH which does not have the temperature correction (it gives the performance according to the altitude density. Fly safe!
Thank you for the comment and the suggestions. I specifically chose to use pressure altitude for this video because the performance charts/tables for all the aircraft my local students fly start with Pressure altitude-Cessna 172N, Piper Warrior, Piper Archer, Cirrus SR series, Mooney M20K, Beech Debonair, and even a later model Bonanza. I recognize not all aircraft start with Pressure altitude (that some use density), but at the time most of my viewers were my local students and I wanted to make it immediately useful for them. I’ll add doing performance calculations using density altitude to my list of video topics. I’ll see if I can find a Sundowner POH or Owners Manual online to use for the calculations. Thanks!!
Awesome video! Thank you so much! I'm trying to get ready for my written test for my private helicopter license and while my school covered every topic there are many topics complicated topics we just talked about for a little bit and then moved on and I never quite understood so now I'm going back through using TH-cam to try and more deeply understand each topic. One thing on this particular topic I've been wondering about is that it seems like practically speaking. Air pressure at a given altitude is mainly determined by the air temperature at that altitude. Does this hold true for the most part?
Thank you! I’m glad you found the video helpful. The simple answer to your question is “Yes”. Differences in air pressure at the the same altitude are mainly influenced by temperature. In fact, page 12-3 of the PHAK states “The unequal heating of the Earth's surface not only modifies air density and creates circulation patterns; it also causes changes in air pressure or the force exerted by the weight of air molecules.” So, according to the FAA, NOAA, and a couple other sources, air temperature has the greatest influence. I hope this was helpful. I wish you the best of luck with your studies!
Gregg. Have you seen my video about Density Altitude. In the video we discuss three ways to obtain density altitude. Here is the link: th-cam.com/video/Mn_c9Kd2Drs/w-d-xo.htmlsi=q-ana3033lt-GD3q Let me know if that doesn’t answer your question. Thanks for the comment!!
Wouldnt the standard temperature and pressure change with each location? An airport at 643ft MSL would have the standard pressure of 29.27Hg and a standard temp of 13.71C°, right? Wouldnt these be the standard from which you would subtract pressure and temp from at this location?
If I am understanding your question correctly, you are asking why we don’t calculate pressure altitude by adding/subtracting current atmospheric conditions from the standard for a specific station. The answer to that is actually in the definition of Pressure Altitude. The definition is “the height above the datum plane”. FAA references specifically define the datum plane as sea level when the temperature is 15C (59F) and the local pressure is 29.92. So, the quickest comparison is between the calculated altitude and sea level during those conditions. I think what you are recommending may be the equivalent of calculating the idealized AGL (above ground level) height for a station. You can likely determine Pressure Altitude by calculating the corrected height above a station, but then you’d still have to take at least one additional step to get the actual height above the datum plane. I hope this helps. If I’ve misunderstood your question, please try asking it a different way. Thanks for asking the question.
Thanks for the question. You are correct. You would start with desired cruise altitude and use the most local altimeter setting to determine enroute pressure altitude. I hope this helps!
Interesting, it would be more helpful, if you could used the Airman Knowledge Testing Supplement. FAA-CT-8060-2H as examples. Also, even thou we can stop and pause your video, if you would slow down speaking (we) could follow more closely.
Thank you for the comment and taking time to make suggestions! This video was specifically intended to focus on methods you might use for your check ride. I added the portions using the PHAK or testing supplement charts to illustrate that methods that can be used on a check ride won’t always provide the specificity necessary for the written test. I’ll add your suggestion to my list of future videos, and look at something addressing skills for the written test. Regarding speed… I’ve been given the opposite feedback, too-I’ll keep working on finding a balance. Thanks again for the comments!
Thank you! I am working on “Calculating Climb Performance” now, and have several others in the queue. Definitely more to come! Do you have ideas regarding what some of my next videos should be?
@@ScottKoonCFI is there any chance you could do one on how to do weight and balance calculations? I haven't been able to find a good explanation in any of the TH-cam videos I've searched for on the subject
Hey Jason. Shoot. Sorry, I missed this comment before. I have two videos on how to do weight and balance calculations. Each video does them slightly differently to show there are a couple ways to accomplish the same thing. I hope you find them helpful. Here are the links! Weight and Balance By Hand: th-cam.com/video/zFU-y27O528/w-d-xo.html Weight and Balance for Piper Archer: th-cam.com/video/QM7AbPii01g/w-d-xo.html
@PodbyBarryB, thanks for the question. I apologize, but I’m not quite sure what you are asking. Let me take a stab at trying to answer what I think you asked. If I missed the mark, please give me a bit more detail about your question. I don’t add the pressure altitude to the field altitudes or altitudes I am going to. Instead, I add a correction value to the field or flight altitude to get a pressure altitude. And, the altitude to which I add the correction value depends on the question being asked. If I am using Pressure Altitude to determine take-off performance, I’ll add any corrections to the departure airport’s stated altitude. If I’m calculating landing performance, I’ll figure the correction based on the altimeter setting at the destination and would add that correction to the destination’s altitude. Finally, if I am looking for cruise performance or climb performance, I’ll add the corrections to the expected in-flight altitudes. I hope this helps. If not, please ask again. Thanks!
Glad to hear I was able to answer your question. I am currently working on an online training series, but it’s not ready, yet. I’ll be announcing it as soon as it is released. Thank you for asking!
Thanks for the question. Actually, many performance charts/tables are based on pressure altitude. We fly Piper Archer IIIs, Piper Warriors, Piper Seminoles, and Cirrus aircraft. All of their performance charts start with Pressure Altitude. So did the Cessna’s we used to fly. The funny thing is that many of our local students are asking why do I need to know how to calculate Density Altitude since they almost never use it. Thanks again!
Unfortunately, it does not. You would need to use a slightly different formula. I don’t practice this regularly, so I might not have it correct. However, I believe to find pressure altitude using hectopascals, you first subtract the current reading from the ISA in hPA of 1013. There is a 30 ft difference for each hPA, so you’d multiply the difference by 30 feet and add the total to the original altitude to get pressure altitude. For example, if the pressure is 1015, the difference would be -2, multiplied by 30 is -60 ft. If current altitude is 1317ft, then the pressure altitude would be 1257. I hope this is helpful.
I have to say that I’m not quite sure how to answer your question. In the video, I go a bit further into the mathematics than is probably necessary. The reason was to demonstrate that in many cases there are “rules of thumb” that provide more than adequate performance estimates. So, do you have to be good at mathematics? Perhaps not. But, you will need to be decent at arithmetic and basic algebra to be able to answer weight and balance, wind correction, ground speed, fuel usage, and other performance questions. While there are tools to help, most DPE want to know you understand the process. To be more specific, not being good at math doesn’t necessarily mean you can’t fly. It does mean you’ll need to work harder and perhaps be creative to find ways to wrap your head around the numbers. I’ve seen students work through similar issues and be very successful. In one case, a student partnered with someone that was VERY good with mathematical concepts and that partner was able to simplify and explain the work in a way that made sense to the student. I’ll keep working to try and find concise ways to describe and define these aviation concepts. I know there are many other video creators trying to do the same. Keep searching for the answers. I hope this helps. Keep working, keep watching, and best of luck!
THANKYOU SO MUCH!! I honestly was really intimidated by all the big numbers but this video made it so easy!!
As you note, the numbers are scary at first, but once you know what they mean, it isn’t so bad. Thanks for the comment! I’m glad the video was helpful!
Really appreciate this
Thanks! I’m glad it was helpful!!
I love this guy. Best online instructor out there
Wow! Thank you so much for the compliment!
He's one of my favorites as well 😀
@rapinncapin123 Wow! Thank you!
Thank you, Captain. Scott for your excellent explanation.
You are very welcome! Thanks for the comment!
This is great!! Subscribed. Finally getting back into flying after a 2 year pause, great refresher!
Glad you liked it! Welcome back to flying!
Finally a video that explained it well. Thanks and please keep posting. You got yourself another subscriber. 👌🏻
Thank you! I’m glad you found this helpful. More videos are on the way. If you have suggestions for topics I’d love to hear them. Thanks again!
Great job... Explanation was very practical to apply.... Thanks!
Thanks! Glad it was useful!
Very helpful, made calculations simple. Ty
Thank you for watching. And thanks for the comment!
Great videos and great refresher for my commercial testing!
Thanks for the comment! I’m glad they are helpful! I wish you the best in your studies!!
After IFR it's hard to go back through the private charts and stuff, but almost done. lol @@ScottKoonCFI
It is, indeed. lol. It doesn’t get any easier when you have to go through them all again for CFI (or CFII)-sheepish grin. Best of luck!
Awesome, just subscribed.
Glad you liked it! Thanks for subscribing!
Thanks Scott...
You are very welcome! Thank you for the comment!
Very good explanation.
Thank you! I’m glad it was helpful!
Thank you so much for mentioning phak page for the correction factor Z that helped me so much to understand this one problem i was having trouble with
You are very welcome. Thank you for the comment!
I like your video. Good explanations. However, I would have preferred to see units used in all graphics and formulas. Finally, I think density altitude is more relevant than pressure altitude regarding aircraft performance evaluation. Pressure altitude can be used in SOME POH; those with temperature correction as in Cessna 172N POH but not for the Beechcraft Sundowner C23 POH which does not have the temperature correction (it gives the performance according to the altitude density. Fly safe!
Thank you for the comment and the suggestions.
I specifically chose to use pressure altitude for this video because the performance charts/tables for all the aircraft my local students fly start with Pressure altitude-Cessna 172N, Piper Warrior, Piper Archer, Cirrus SR series, Mooney M20K, Beech Debonair, and even a later model Bonanza.
I recognize not all aircraft start with Pressure altitude (that some use density), but at the time most of my viewers were my local students and I wanted to make it immediately useful for them. I’ll add doing performance calculations using density altitude to my list of video topics. I’ll see if I can find a Sundowner POH or Owners Manual online to use for the calculations.
Thanks!!
Nice 👍
Thank you!
Awesome video! Thank you so much! I'm trying to get ready for my written test for my private helicopter license and while my school covered every topic there are many topics complicated topics we just talked about for a little bit and then moved on and I never quite understood so now I'm going back through using TH-cam to try and more deeply understand each topic. One thing on this particular topic I've been wondering about is that it seems like practically speaking. Air pressure at a given altitude is mainly determined by the air temperature at that altitude. Does this hold true for the most part?
Thank you! I’m glad you found the video helpful. The simple answer to your question is “Yes”. Differences in air pressure at the the same altitude are mainly influenced by temperature. In fact, page 12-3 of the PHAK states “The unequal heating of the Earth's surface not only modifies air density and creates circulation patterns; it also causes changes in air pressure or the force exerted by the weight of air molecules.” So, according to the FAA, NOAA, and a couple other sources, air temperature has the greatest influence. I hope this was helpful. I wish you the best of luck with your studies!
@@ScottKoonCFI thank you so much!
Would you be willing to show the basic formula for calculating Density Altitude AWOS information? Thank you.
Gregg. Have you seen my video about Density Altitude. In the video we discuss three ways to obtain density altitude. Here is the link: th-cam.com/video/Mn_c9Kd2Drs/w-d-xo.htmlsi=q-ana3033lt-GD3q
Let me know if that doesn’t answer your question.
Thanks for the comment!!
@@ScottKoonCFI
Thanks Scott!
You are very welcome! Thanks for asking!
Wouldnt the standard temperature and pressure change with each location? An airport at 643ft MSL would have the standard pressure of 29.27Hg and a standard temp of 13.71C°, right? Wouldnt these be the standard from which you would subtract pressure and temp from at this location?
If I am understanding your question correctly, you are asking why we don’t calculate pressure altitude by adding/subtracting current atmospheric conditions from the standard for a specific station.
The answer to that is actually in the definition of Pressure Altitude. The definition is “the height above the datum plane”. FAA references specifically define the datum plane as sea level when the temperature is 15C (59F) and the local pressure is 29.92. So, the quickest comparison is between the calculated altitude and sea level during those conditions.
I think what you are recommending may be the equivalent of calculating the idealized AGL (above ground level) height for a station. You can likely determine Pressure Altitude by calculating the corrected height above a station, but then you’d still have to take at least one additional step to get the actual height above the datum plane.
I hope this helps. If I’ve misunderstood your question, please try asking it a different way.
Thanks for asking the question.
How would you go about calculating PA for cruising performance charts? Instead of adding airport elevation would you add desired cruising altitude?
Thanks for the question. You are correct. You would start with desired cruise altitude and use the most local altimeter setting to determine enroute pressure altitude. I hope this helps!
LOVE your content. Prepping for the CFI ride, and this helps a ton!
Excellent! Best of luck and welcome to the club!!
Interesting, it would be more helpful, if you could used the Airman Knowledge Testing Supplement. FAA-CT-8060-2H as examples. Also, even thou we can stop and pause your video, if you would slow down speaking (we) could follow more closely.
Thank you for the comment and taking time to make suggestions!
This video was specifically intended to focus on methods you might use for your check ride. I added the portions using the PHAK or testing supplement charts to illustrate that methods that can be used on a check ride won’t always provide the specificity necessary for the written test. I’ll add your suggestion to my list of future videos, and look at something addressing skills for the written test.
Regarding speed… I’ve been given the opposite feedback, too-I’ll keep working on finding a balance.
Thanks again for the comments!
keep making videos!
Thank you! I am working on “Calculating Climb Performance” now, and have several others in the queue. Definitely more to come! Do you have ideas regarding what some of my next videos should be?
@@ScottKoonCFI is there any chance you could do one on how to do weight and balance calculations? I haven't been able to find a good explanation in any of the TH-cam videos I've searched for on the subject
Hey Jason. Shoot. Sorry, I missed this comment before. I have two videos on how to do weight and balance calculations. Each video does them slightly differently to show there are a couple ways to accomplish the same thing. I hope you find them helpful. Here are the links!
Weight and Balance By Hand: th-cam.com/video/zFU-y27O528/w-d-xo.html
Weight and Balance for Piper Archer: th-cam.com/video/QM7AbPii01g/w-d-xo.html
@@ScottKoonCFI awesome! Thanks so much! I'll check them out!
Legend 🙏❤😅
Thanks again!
Great video!!! Do you always add the PA TO THE Field elevation or altitude you're going to?
@PodbyBarryB, thanks for the question. I apologize, but I’m not quite sure what you are asking. Let me take a stab at trying to answer what I think you asked. If I missed the mark, please give me a bit more detail about your question.
I don’t add the pressure altitude to the field altitudes or altitudes I am going to. Instead, I add a correction value to the field or flight altitude to get a pressure altitude. And, the altitude to which I add the correction value depends on the question being asked. If I am using Pressure Altitude to determine take-off performance, I’ll add any corrections to the departure airport’s stated altitude. If I’m calculating landing performance, I’ll figure the correction based on the altimeter setting at the destination and would add that correction to the destination’s altitude. Finally, if I am looking for cruise performance or climb performance, I’ll add the corrections to the expected in-flight altitudes.
I hope this helps. If not, please ask again. Thanks!
@@ScottKoonCFI that was perfectly clear Scott! Thank you for the speedy response as well.
Do you do online based ground training?
Glad to hear I was able to answer your question.
I am currently working on an online training series, but it’s not ready, yet. I’ll be announcing it as soon as it is released. Thank you for asking!
@@ScottKoonCFI ok Ill keep my eyes out...
can you do one for density altitude please?!?
Funny you should ask. That is what I’m working on, now. Hopefully will be released this week. Thanks for the request!
Why do you care about pressure altitude, though (apart from passing an exam)? Isn't it just a step towards calculating the density altitude?
Thanks for the question. Actually, many performance charts/tables are based on pressure altitude. We fly Piper Archer IIIs, Piper Warriors, Piper Seminoles, and Cirrus aircraft. All of their performance charts start with Pressure Altitude. So did the Cessna’s we used to fly. The funny thing is that many of our local students are asking why do I need to know how to calculate Density Altitude since they almost never use it. Thanks again!
@02:00 Does his equation also apply for hecto pascals?
Unfortunately, it does not. You would need to use a slightly different formula. I don’t practice this regularly, so I might not have it correct. However, I believe to find pressure altitude using hectopascals, you first subtract the current reading from the ISA in hPA of 1013. There is a 30 ft difference for each hPA, so you’d multiply the difference by 30 feet and add the total to the original altitude to get pressure altitude.
For example, if the pressure is 1015, the difference would be -2, multiplied by 30 is -60 ft. If current altitude is 1317ft, then the pressure altitude would be 1257. I hope this is helpful.
Ahhh Yes, I got it, sir :)@@ScottKoonCFI
Rise over run bro wtf
I’ve not heard of using rise over run to calculate pressure altitude before. Can you give an example?
I' m so bad at math. This makes me want to cry. I'm really intelligent but math just doesn't work in my brain. Does this mean I can't fly? 😢
I have to say that I’m not quite sure how to answer your question.
In the video, I go a bit further into the mathematics than is probably necessary. The reason was to demonstrate that in many cases there are “rules of thumb” that provide more than adequate performance estimates.
So, do you have to be good at mathematics? Perhaps not. But, you will need to be decent at arithmetic and basic algebra to be able to answer weight and balance, wind correction, ground speed, fuel usage, and other performance questions. While there are tools to help, most DPE want to know you understand the process.
To be more specific, not being good at math doesn’t necessarily mean you can’t fly. It does mean you’ll need to work harder and perhaps be creative to find ways to wrap your head around the numbers. I’ve seen students work through similar issues and be very successful. In one case, a student partnered with someone that was VERY good with mathematical concepts and that partner was able to simplify and explain the work in a way that made sense to the student.
I’ll keep working to try and find concise ways to describe and define these aviation concepts. I know there are many other video creators trying to do the same. Keep searching for the answers.
I hope this helps. Keep working, keep watching, and best of luck!