Pressure Altitude vs Density Altitude | Private Pilot Knowledge Test | FlightInsight
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- เผยแพร่เมื่อ 5 ส.ค. 2024
- What do you need to know about Pressure Altitude and Density Altitude on the FAA Private Pilot Knowledge Test? Visit flightinsight.teachable.com/p... to learn more!
The air we fly in is never the same. The density is affected by altitude, air pressure, temperature, and humidity. We need an easy way to compare different conditions on different days so we can predict how well the airplane will perform.
This is what the International Standard Atmosphere is all about. It's a fantasy land, where the pressure and temperature are always the same no matter what.
In this fantasy land, the conditions are always:
Sea Level Pressure: 29.92 inches of Mercury
Temperature: 15°C at Sea Level
Lapse Rate: Temp drops 2°C for every 1000' of altitude
So Pressure Altitude is the altitude we'd be flying at in this fantasy land if we were experiencing a certain pressure. Density Altitude takes it a step further and gives us the altitude we'd be at in fantasy land under a given pressure AND temperature.
Pressure Altitude vs Density Altitude | Private Pilot Knowledge Test | FlightInsight
I’m a 33 hour Pilot getting ready for my checkride in the next 10 or so hours and I am taking ground school test next week and this is literally the FIRST time I’ve actually fully understood this. Thank you so much.
You have a gift for breaking down concepts into bite size understandable chunks. So helpful thank you.
This was amazing, easiest to understand explanation I’ve seen, thank you!
You're very welcome!
As you can tell from all of these comments, your ability to explain things is remarkable. Your explanation with the illustration is truly a gift.
Wow, I am super impressed with how clearly you explain concepts. I would love to see a complete series on aviation weather at ATPL level
Thanks, so much! And a series on ATP weather sounds like a great upcoming project.
This is by far the simplest explanation of the different altitudes. Profound thanks!
This was the best I’ve ever had PA vs DA explained. Thank you!
@FlightInsight
1:10 Higher temperature does NOT create lower pressure. Higher temperature is a result of increased kinetic energy and creates HIGHER pressure. It is this higher pressure that causes the volume of gas to expand, creating a lower density. This lower density degrades airfoil performance, and increases density altitude.
EDIT: I should add that your videos are excellent though!! Very helpful for students!
Since we're being pedantic, generally, higher temperatures will lead to lower air pressure. This relationship is described by Charles's Law and the Ideal Gas Law. According to Charles's Law, when the temperature of a gas increases, its volume expands if pressure remains constant. However, in the atmosphere, if the volume remains constant (which it approximately does in a given region), an increase in temperature causes the air molecules to move faster and spread out, resulting in a decrease in air density and thus lower air pressure. Nevertheless, I don't think this was something that needed to be commented on.
After so long of giving myself headaches and even wanting to give up on the topic, this video finally made me understand.
Sometimes you have to step away from the fancy FAA/ground school to really understand a topic.
Going for my CFI soon and rewatching these to see how to properly teach them. Thank you.
This video is the Holy Grail of Pressure and Density Altitude. Thank you. The graphics are great for visual learners.
At 5:06, I think you mean to say 25 degrees, not 20 degrees, since field temp is 25?
What a great session. This was the #1 thing I was having difficulty with and moved my knowledge test 3 times cuz I wasn't comfortable with this. GREAT JOB.
So helpful, thank you! Great explanation of the relationship between pressure & PA and temp and DA
Excellent explanation. The graphics illustrating the relationship between pressure, temperature and altitude was the best I have seen.
I've been going over this section in King schools training and it was't clicking. This was extremely helpful in understanding the difference between PA and DA as well as how pressure and temperature effect them.
Thank you for doing this video! So good! I needed a review & this was perfect👏🏼
Your way of explaining these things is spot on. Excellent explanation. Thank you
Thank you very much for sharing this. Well explained! It definitely helped me to understand this better.
Echoing others. I will never forget what density altitude is now, thanks to your work here. Thank you!
This video is gold! The visuals were very helpful in trying to understand something on a micro level. I found myself think if only someone could make a diagram and then found this beauty. Thanks for this!
Glad you found use for this. Thanks for watching!
Thank you! That was pretty straightforward.
Thanks, exactly what I needed! Very well explained!
Quite easily the best explanation I have seen yet
Helped a lot, thank you so much!
Maaaan, it's the best explanation I've ever heard. Damn gooood work. Keep it up!
This was a fantastic video, great explanation, simple to understand and great visuals. Thank you!
Thanks as always Abby! When's your next vid?
Such a great video thank you!!
This video, along with your other videos are such a monumental help with my studying for my PPL. You can't find any other channels or videos on youtube that describe or teach aviation topics in a way that's so easy to understand such as this.
So glad to hear it, good luck!
This is awesome. Great explanation of a very confusing topic. Thank you
This tutorial let me understand this topic so well. Good explanation.
You did a great job on this, makes sense now. Thank you
Wow. You are very talented at explaining.
The easiest to comprehend video on density altitude I have found out of a dozen, and explanation to what even den altitude is was provided.
I still find it easier, though, to use the simple math in my head instead of using the chart ahahah.
Thanks so much! I tend to like the math and formulas better too, but I think we're in a minority there, as most people do better with the visuals!
Great Explanation, thank you
It help me to understand great video. Thankyou!
Awesome thank you! I understood it
Clear and to the point; very well done sir!
Glad you enjoyed!
Very good and clear!
Such a great video.
Amazing video. The best I have seen on this subject. Very clear, thanks
You’re most welcome, thanks for the feedback!
This is literally the BEST video on this topic...
Thanks
Thanks for watching Jeremy!
bro this was awesome
thanks so much
Excellent, excellent video! Thank you.
Glad you enjoyed it!
Excellent explanation.
This is the best explanation I've seen on this topic, BAR NONE!!! I was a bit thrown off by the speaker stating a temperature of "20" degrees during the example, while the video used 25 degrees in the calculations. I was able to figure out the discrepancy and get past it though; so I indeed got the full benefit of your presentation. So yes... kudos are in order!! Excellent work!!
So it's true? There was a discrepancy and it wasn't just my brain laocking up? What Is the correct math then?
Since air molecules are less dense in high altitude, why the cold temperatures "at high altitude" won't make the molecules dense again ? In other words, who wins in this case ?
Mind blown. so easy now!
Very nicely explained.
Really great video
This is really helpful! More videos please!
More coming up! Thanks for the support!
This was an excellent video. Thank you
Thanks! Appreciate the feedback
On your check ride when asked about density altitude, although it is correct ( density altitude is pressure altitude corrected for the non-standard temperature) a lot of DPEs don’t like that answer so be prepared to give a little better definition
such a great explanation, thanks!
Thanks for mentioning it! Hope it was helpful.
Thanks
u got subs from me my man. kudos and keep em coming
Thanks for the support and welcome!
kept zoning out during the sportys ppl section explaining this... you did a better job!
Great Video. Thanks
Glad you enjoyed! Thanks
Hello FlightInsight, I have an observation. The terms "PRESSURE ALTITUDE" and "DENSITY ALTITUDE" are confusing because they are using a DIFFERENT term to explain the SAME ELEMENT in the mechanism that makes the ALTIMETER move. What is the ELEMENT that moves the ALTIMETER? The AIR MASS which changes its "DENSITY" depending on the following factors: 1) Atmospheric Pressure 2) Altitude 3) Temperature and 4) Humidity. Therefore, if they are going to use the factor that alters the air mass that pushes the aneroid wafer in the altimeter to come up with a different term for "ALTITUDE" then there should be a corresponding term for each factor, for example: 1) Atmospheric Pressure Altitude 2) Elevation Altitude 3) Temperature Altitude and 4) Humidity Altitude, because each factor has a different effect (response of the Altimeter) on the air mass "DENSITY" which is the one moving the needle of the Altimeter. That is what the graph in the chart is trying to explain for those 2 different concepts. So maybe you could escalate this explanation to the FAA and make is easy for us the Student Pilots to understand. If the factors 2 and 4 are not relevant to the response of the Altimeter or have a very small effect on its behavior then it is ok if only 2 are left but it would be easier to understand by using the proper term for the concept. It seems like the term of "DENSITY ALTITUDE" is the one making things more confusing since the Atmospheric PRESSURE changes the air mass DENSITY so maybe it would be good to use "Temperature Altitude" instead. At the end, we will still be looking at the SAME INSTRUMENT anyways.
Just to clarify , the “high to low look out below” applies to both pressure and temperature or just pressure ?
What can I get from seeing that my GPS says my altitude is 1,000' but the atmospheric pressure reading is higher or lower than ISA of 28,92inHg?
Fantastic
I just turned a 5 minute video into an hour long video by tapping rewind so much to understand..
I felt that
Same, perfectly fine, you're human and learn at your speed. Just the fact that you're here trying to learn is excellent. Keep it up.
That's good 👍
Same huhuhuh
Omg same hahahaha
ty so much more videos on these topic pls
You're most welcome. Anything particular on pressure/density altitude you'd like to see? I do have some other videos on the topic but have been thinking about doing another on a specific area. Thanks for watching!
thanks 😊 is very helpful
Thanks for watching!
But how do you use this info to... lets say.. not fly into a death trap canyon or mountain pass?
so in a sense for every 15°F of increase our pressure altitude increases as well right?
so this means if i fly under the ocean, Ill go real fast right
Indicated altitude is equal to true altitude when the pilot sets the altimeter using:
29.92"Hg is this correct
OK, we have calculated the density altitude. Now what do we do with that number? The aircraft performance charts use pressure altitude, not density altitude and I see no performance charts that use density altitude.
when you say that temperature increases is is cold or warm ?
I'm confused on how pressure altitude and density altitude aren't directly related. How could a given volume of air at a certain altitude retain the same pressure over a range of temperatures? Isn't the performance of the aircraft dependent only upon the pressure, and thus the factors of altitude and temperature affect the performance of the aircraft only insofar as they affect the air pressure? So wouldn't a deviation from standard temperature already be accounted for in the pressure itself, given that the pressure is as it is in part _because_ of the temperature?
1:22. High presurre air goes outwards not inwards?
An increase in altitude causes an increase in density altitude? Is that correct? 3:21
nice explanation.
Thanks, I'm glad it helped!
Can someone help explain this to me. Let’s use KLAF airport (Purdue Airport). Field elevation of 606ft. If I am sitting on the runway with standard pressure altitude of 29.92 inHg the altimeter will read 606ft. I get that part. But now let’s say the altimeter setting is 30.35. I roll that in and the altimeter raises to 606 ft. I get confused on inputting a higher pressure in than standard pressure altitude and the altitude increases. Doesn’t a higher pressure mean more air molecules and there for I should be reading a lower altitude below the airport elevation? (I know thats know right its just how my mind is thinking). Looking for a good analogy/explanation to understand what is actually happening.
Actually i get it now after I thought more about it. The altimeter setting is what pressure sea level would be at and NOT where you are currently sitting at. I was thinking sitting on the runway the pressure is 30.35 but its actually lower than that. The 30.35 is what the pressure would be like 606 ft below me where sea level is. The altimeter senses lower pressure via the static port than 30.35 since I am higher than that.
500th time watching this
why dont flight schools and books explain it like this.. so simple that everyone can understand it!!!thank y
The biggest reason for flying at higher altitudes lies in fuel efficiency. The thin air creates less drag on the aircraft, which means the plane can use less fuel in order to maintain speed.
Didn’t hear this fact in the video
im confused, couldn't understand
you said 20 degress f but example reads 25 f
Why does this have to be so boring