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
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.
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!
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!
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
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.
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 .
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.
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?
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 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.
