Density Altitude Question 8-47 on Page 8-30 PART 1

[@KINGSPARKLZE]

I'm from Australia and we use the pressure unit hPa (Hectopascals). The formula I have been taught is very simple. It is as follows: 1013 (which is ISA pressure), subtract the QNH, once you get your answer multiply it by 30 and then once you have multiplied by 30, plus the elevation or altitude. For example if the QNH was 1016 and your elevation was 1500: PA=(1013-1016)x30) + 1500 Answer: PA=1410 This seems really complicated but it isn't, and if you understood it you could do the simple conversion and convert the QNH from inHg to hPa and work out the pressure altitude by doing this. Anyways I hope this makes sense. Aaron

[@timbyrne914]

Practically speaking this rule is close enough, but for the exams here in the states it's safer to use the tables when they cite tables. They often use more precise non-linear functions. The extra accuracy is more or less pointless, but to get to the answer they are looking for on the exam you probably need to use the table. E.g. using the table he's using (after conversions) I'd get 1427. That may or not be close enough a one and only one of the multiple choice answers to get it right. I can't imagine using tables like this in real life though. I either use a quick linear approximation like yours or I use a flight calculator app.

[@andychris6069]

I'm a freshman in college studying Flight Science 1. This helped me so much, I was so lost on interpolation and this method made it so clear so quick. Thank you!

[@fernandogomez4386]

This video and Part 2 are by far the most helpful videos I’ve come across for solving these types of equations. Outstanding explanation and instruction, well done!

[@stevesayer4045]

This is on of the best video iv ever seen thank you very much mate 👍

[@captaingregger]

Dr. Fellar, I truly appreciate all the effort you put into simplifying these calculations, to make it easy for us to learn. Thank you!

[@michaeljohn8905]

Will this work for interpolating landing role? , or any graph ? I’m having a hard time with the graphs if I need to interpolate. Thank you for this video. Mike KLZU

[@a4aviator294]

How do you interpolate between just two numbers? For example, 157 knots and 160 knots, the book says it’s 158 , what’s an easy formula for that?

[@michaeljohn8905]

Does this Work for all types of interpellation ?

[@haroonsurkhabi3387]

Thank you so much!❤️

[@flyod26]

Thank you so much!!

[@sarathw5740]

Thanks, I just notice a short cut. 1380+1630=3010 (answer A) and 1380+1533=2913 (answer c) So the correct answer should be answer B

[@essanasseirjaafar7159]

Thanks 🙏 doctor

[@tamy815]

Does the humidity influence the pressure altitude?

[@vadermike7772]

TS B no, pressure alt, is only based on the atmospheric pressure at that specific ,at that specific location.

[@balto2455]

@@vadermike7772 but relatively it does... if the air is humid... the temperature will drop slower then dry air... and so does the pressure

[@cbrown745]

Hello Sir, Where can I order the latest manual from?

[@OzyOzySM]

don't know why the youtube put cross line on my questin but my q was regard the lower minus Alt setting my example was 30.35 and the Elev was 3894

[@1312cc]

You're supposed to remember all this without referring to previously written instructions? Really?

[@lanzfraginal8519]

Why cut it

[@battmann678]

1 minute of information in 8 minutes...

[@michaeljohn8905]

1 minute use of time to make ungrateful comment . 8 letters to simply say THANK YOU .. even though it didn’t help you much. Learn that trick and you will go further in life my friend.

[@OzyOzySM]

this is great video, thank you so much for all your efforts to make this video and simple explaning Just wanted to ask you question here; if the question comes from the (-) altitude let say Alt 30.35 what you do regards the math do you revers them in other word do you subtract -348 - (-440) then you have -780 and its wrong but if we don't count the - for the alt w will have (348-440)=-92 then the -92 divided on .1 X .05 you will have -46 then this time you should take the (-) when you subtract the -348 -(-46) to have -394 then add+ to the given indicated alt let say 3894 = 2500 pressure ALT correct?

[@JoaoAmadoTV]

Here's the link for PART 2 - kzbin.info/www/bejne/gHS9i3-kdt5_aKc

[@JoaoAmadoTV]

PART2 - kzbin.info/www/bejne/gHS9i3-kdt5_aKc

[@GZA036]

The idea that someone who is going to be flying a plane would need math explained this slowly is pretty scary

[@brandon5058]

Just curious, how did you come here? xDDD

[@timbyrne914]

Nobody actually needs to know how to interpolate in 2018. One does this because the FAA still has one foot in 1950. Old GA aircraft handbooks do have lots of tabular data, but nobody uses those. All of the calculations have been available in apps for a long time now. It's safer to use the apps. Carrying a tablet plus a phone gives you a sufficient backup.

[@margeolsen6657]

If he doesn't hurry up and figure this out fast someone is going to be cleaning up the pieces of the plane on the side of a mountain

[@fun782house]

The good pilots are the kids that start out with life's empirical lessons in physics like playing baseball, football, racing motorcycles, skateboarding , surfing , snow skying , riding unicycles , and so on , not the nerds who spend all day studying and competing in mathlete tournaments .

[@JoaoAmadoTV]

@@timbyrne914 you can't take table or phone to a FAA exam ...

[@Snowbrdr020]

Why in the world you would make this calculation so difficult??? This is a very simple proportion problem. 28.2 / 1630 = 28.22 / x Cross multiple ! 28.2x = 45998.6 Divide ! x = (45998.6 / 28.2 ) x = 1631.15' OR JUST 1631' Add ! 1631' + 1380' = 3011' So you would choose 3010' You just over complicated this for absolutely no reason and wasted a lot of time. No one should memorize the way it is shown in this video...

[@sarahsdandelions]

You just made that way more complicated.

[@Snowbrdr020]

@@sarahsdandelions thank you for replying to a three year old comment. Glad you stopped by. Yes, two easy steps and you have an answer... So much more complicated.

[@MobbyG]

I haven't seen a link for the worksheet so I made a quick and dirty one... drive.google.com/file/d/1YYZ8ULNc-H-jfHUg8mxelT0sjWbn95ck/view?usp=sharing