How do the Altimeters work and what is a Flight Level?

brilliant.org/MentourPilot/
In this video I will give you an insight into how pilots use the altimeters onboard the aircraft, how they work and why we use Flight levels above certain altitudes.
It is an overview of the subject and for more knowledge of the physics behind i recommend you to check out our Sponsor, Brilliant.org, using the link above.
To get the answer to the question in the video, check the following link:
Https://Brilliant.org/MentourEdge/
To download the Mentour Aviation app, use links below:
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[@davidhouse5073]

A born “great teacher and communicator”. I’m brand new to aviation, but I know that “words mean things” and mental images are golden. You anticipate follow-up questions extremely well because you actually put yourself in the shoes of us who are FAR LESS experienced. Great job.

[@yabatulij]

He explains better than my flight instructor

[@MentourPilot]

Haha, thank you!

[@yabatulij]

Thanks for doing what you're doing, we appreciate it very much. Keep on the good work 👍👍

[@baljeep_gay]

same for me, mine is xp11 flight school.

[@CaptShami]

Ha!

[@philchia4764]

Maybe because he IS a flight instructor as well! But you know, big boy planes

[@TheFlyMan]

You, Captain Joe and Sully Sullenberger are my inspirations. Thanks for the videos. 😁

[@SemyrasGerkhanas]

Another great video Mentour. You are like captain Sullenberger but youtube one! The content you giving is amazing! Much respect for YOU!

[@TCPUDPATM]

This is one of your best technical videos! Could you also talk in detail about pitot tubes next?

[@typicalnick4176]

best channel ever! it answers all my questions about aviation! Thanks Mentour

[@delboy365]

Extremely informative video as always. Excellent! Many thanks for the videos......👍

[@MentourPilot]

Thanks! Glad you liked it!

[@1Miguellima]

Thank you Mentour for this explanation, it help me to understand Altimetry, something I have been studying and trying to understand .

[@dronesmedia6356]

Thankyou mentour pilot so much for everything you have done! Also Thankyou so much for inspiring me and showing me new stuffs about aviation. I’m currently taking PPL licence and finished my RPL and I am hoping to finish my CPL as soon as possible so I could go to my favourite airline Cathay Pacific!Also when I was at school people laughed at me on what I want to be! So right now everybody don’t listen to you those people if they had laughed at you or bullied you on what you want to be! Remember that that’s not there dream that’s yours and you should stand for it and succeed! Thankyou again mentour pilot for everything you’ve done! Hope to see more of your vids!!

[@NOOne-li1pj]

Drones media wow! Good luck on your trainings!

[@Raydawg]

I love these videos, thank you for the time and effort

[@engCybernetics]

I spotted the MATLAB figure "peaks" :) Very nice! Also: Very good explanation. Thank you!

[@EduWushu]

Man thanks a lot. Im getting my PPL now and in the theory course this part was not explained very clearly. This clarified everything I needed to know. Excellent channel btw! I've seen tons of your videos

[@mariushelland618]

Nice to see where this channel is heading :) almost 100k now! congratz!. Btw i love the videos from the cockpit

[@danielbuczynski741]

Really interesting video. You are quite skilled at explaining technical things. Keep it up!

[@grzegorzciebiera476]

Well explained, Mentour! Please, do more videos like this one :)

[@johnthegreek7356]

Almost 100k... Congratulations Peter

[@MentourPilot]

Thank you, soon my friend.

[@lyndakourtel6418]

Thank you so much for sharing your knowledge captain, I am a student pilot and I was struggling with these notions, now it’s so clear.

[@razamh7029]

That was quite informative, thanks dear captain keep going!!

[@prereed]

Excellent explanation about flight levels. Thank you.

[@ButterfaceGMusicSlump]

Love the question at the end! Really makes me get involved with this video. I will definitely figure it out.

[@samerhaddad280]

wow! I've always wanted to know about this subject. these videos are opening my mind's eye to aviation, thank you captain

[@royalfolkspark]

It will soon change.......using (Lidar)........

[@johnny_pilot]

@@royalfolkspark Lidar being used to measure altitude (range)? I know it is used for ground penetration for short distances but for thousands of feet? Really? 🤣

[@andyross37]

I've just signed up to your Patreon crew! Love your videos!

[@neoepicurean3772]

Thanks. I'm trying ATC and this was a great introduction.

[@theredeemedofthelord1347]

Hope you were able to complete it

[@7.3ididiesel36]

Enjoyed the video, very well explained.

[@p11111]

Great, informative video as always!

[@kevinbrennan8794]

Great details and explanation. Thank you Captian.

[@hensleygarcia1623]

Learning a lot of this guy, keep.doing great videos!

[@santiagofernandez880]

Excellent video. I have learned a lot about aviation thanks to you. Keep going.

[@paddy6494]

Awesome 👏 .. I am working on cfi .. and going to break down exact the same way you did .. thank you so much ..

[@paulbrosnan4339]

This title looks a lot better now. Another excellent video my friend. I'm delighted to be part of your crew. Keep em coming 😀

[@MentourPilot]

Thanks! Great to have you onboard!

[@captkay5330]

I was waiting for this video for a long time thanks mentor.

[@MentourPilot]

I hope you liked it!

[@captkay5330]

Mentour Pilot of course I did

[@mrniceguy9653]

Silver Play button on its way. Happy flying mate :)

[@MentourPilot]

Thank you! Yes, it’s close now.

[@lrscompany1817]

thank you for all you do mentour 💙✈

[@alankritatiwari3033]

Perfect demonstration of FL thanks a lot sir

[@naryah22]

Outstanding explanation, thanks.

[@LeoRdgz]

Excellently explained! 👏👏👏

[@zacharieaertssen3462]

One of the reasons why i want to become pilot, when i watch your videos i only want it more :) Keep making videos, you explane it so clearly.

[@hugo-kikecastillomyfavorit7548]

You are a pro! Thanks so much this helped a lot. 👍🏻✈😎

[@hmabboud]

The best one explaining this topic with live example.

[@SamuelJeffrey-tt1cz]

Wow I love this guy I wish I can have an instructor like him

[@RahmanSajid]

Another great and wonderful video Petter! This would definitely help us student pilots 😉

[@turbofanlover]

Outstanding vid, sir. :)

[@grandroatan1273]

I love em, he explain so sweet.

[@bobjones5166]

I'm a skydiver and have one of my many altimeters sitting just under my computer monitor. I zeroed it out on a day when the local pressure was the same as the altitude of the local area. I now use it to see what the weather is doing. Right now it is showing a +500 feet in altitude. So we have a low pressure system moving through, and the MASSIVE thunder storms to prove it. lol By keeping an eye on it I can get hours notice of storms moving through. And by seeing how fast it is changing can tell how severe it may get. So just another use for an old altimeter.

[@johnny_pilot]

Nice!

[@therealax6]

Most people use barometers as altimeters. You use an altimeter as a barometer :P

[@johnlama5577]

Such a good video!

[@MentourPilot]

Great! I’m happy you liked it!

[@HorizonGBRS]

Great video Petter, fantastic explanation also just 3k more subs to go 😀

[@raesracingteam1595]

THX a lot 4 T videos! I really like them a lot!

[@Dkriedt]

Wouldn't the QNH at the airport Tower where your leaving from be the same as your reading on the plane's altimeter since they're both based on the local air pressure?

[@Freddy-ox3rt]

awesome stuff as always

[@alandetiberiis4312]

Tried to figure this out and I hope you’ll share your answer: to get to an atmospheric pressure of one pound per square foot, you would need to get to an altitude of 81 kilometers above planet surface (about 50 miles up) based on the definition of “space” you provided.

[@mati327]

Lovely work mate

[@stylishlabrary9552]

Love your explanation

[@WillSmith63957]

Mentour is one of the best guys out there. Love him

[@Blast6926]

wow, that's really good video, thanks, i learned something new today

[@MentourPilot]

Every day you learn something new is a good day!

[@vprincessfan12]

Great video as always! Very easy to watch and comprehend. On a somewhat unrelated note, as someone going into the rail industry, it can make me a bit uncomfortable when I fly a route that could be done by rail but for whatever reason I need to fly. Do pilots have a similar experience when traveling by train/bus/whatever?

[@MentourPilot]

No, I really enjoy the comfort of trains. It’s the speed Im after.

[@Xlastsuspectx]

Love it when you do your vids in the cockpit! Keep it up Cpt! God (tidlig) helg!

[@MentourPilot]

I do my best but it’s not always possible.

[@Xlastsuspectx]

Oh yeah, thats understandable. :)

[@gorillaau]

I loves the video which was shot in an aircraft toilet... discussing why there is an ashtray when you are not permitted to smoke on board.

[@elenacolon3880]

thank you captain , very well understood

[@jolyonwelsh9834]

I love the 400Hz whine in the background.

[@tzvikirimler8257]

Great lesson!

[@clifford4200]

Good job. I understand it now better than ever.

[@RahmanSajid]

3K till 100K! Petter, early congrats mate

[@CaptainBobSim]

Thank you so much for contributing to aviation- I can not wait until next Thursday! I was watching your live videos- I hope you resist swearing (It just kinda puts me in a bad mood) Thanks again!

[@eliekadi4297]

Nice video love it as all the videos you make

[@MentourPilot]

Thank you! I’m glad to hear that!

[@eliekadi4297]

Mentour Pilot have you ever flown to lebanon?

[@tygranamalyan]

Great video!

[@aymannaes3321]

Great video

[@MentourPilot]

Thank you!! Glad you liked it!

[@Ep339]

Love your vids

[@MentourPilot]

Great!

[@fanoooooo6]

excellent explanations m cheers fella , top bloke

[@ivojuhrend]

Great video again!

[@MentourPilot]

Thank you! Glad you liked it!

[@akivatalansky]

Great explanation, I enjoyed it. I'm not a pilot, maybe one day, but I have studied meteorology, so I'm familiar with these subjects.

[@user-is8hd7ph4n]

Thanks a lot. I understand much better now.

[@tituslim4648]

Great video as always

[@nothke]

How is this comment 3 days old??? You hacked youtube! :D

[@MarcQuiclic]

nothke May be a Beta Tester that got the link earlier than us

[@tituslim4648]

i'm mentours patreon subscriber :) we get to view the videos earlier by a few days

[@w6wdh]

The pressure decrease with increasing altitude is linear only for small changes in altitude. A much better description is an exponential function, where pressure decreases by 50% for every 18,000 feet (approximately) of increased altitude. So at 36,000 feet, the pressure is 50% of 50% which is 25% of sea level pressure. You can see why this is the case from what you learned in your physics classes. Whatever your height, every square centimeter of horizontal area is supporting all the air above in a 1 centimeter square column. So as you descend, the air pressure increases exponentially, doubling for every 18,000 feet you descend. This happens because there is more weight of air to support as you descend. (The numbers change a little bit with air temperature and weather fronts. Also the temperature of the atmosphere increases above a certain height, which complicates things.) If our altitude is 180,000 feet, that is 10 times 18,000 feet. Using our simple exponential model, the pressure is 2^-10 or 1/1024 or about 0.1% of sea level pressure. (NASA commonly defines the atmospheric entry altitude as 250,000 feet, so this isn’t far off.) Wikipedia has complete formulas and background information. For example, Google “wikipedia barometric formula” or “wikipedia altimeter”. Per Wikipedia, an aircraft altimeter displays height as the logarithm of the air pressure, following the equation z = c T log(P/Po) where z = height, c = a constant, T = absolute temperature, P = measured pressure, and Po = sea level pressure.

[@luicanettieri5607]

Phenomenal 👍🏽 thanks

[@ashleymalamute]

I was wondering this just a few weeks ago!

[@LastenZa]

My hero 😀😀😀😀 thx for those explications

[@letsgo7466]

Sir if you upload such type of videos surely in no time you are gonna hit 1million subscribers

[@kikiday8999]

Although the altitude I got seems not right, but this is my thought. The change in altitude means the change in pressure so we work out the difference between the standard atmosphere pressure and 0.001(which is 0.1 percent) of standard atmosphere pressure, so 1013.25-(1013.25 x 0.001)=1012.24 hpa. ''And every increase of 1 feet the pressure gone to drop by about 1 hpa'' quote from the videos, so I use 1012.24 x 30 and I got 30367 feet which doesn't seems right.

[@paulofrome]

good one thanks

[@karfahichem5243]

Thanks for the video.can any one post the method of calculation though...cant access the link.

[@tigertiger1699]

Always wondered... 👍 lol logical n simple... man aviation is so cool.. We truly have stood on the shoulders of giants 🌹

[@torben.u.f4722]

I Hope you had have a nice flight to Baden Baden keep UP with your nice videos

[@sweiv]

Thanks!

[@alimadani1783]

Thanks a lot for every thing

[@gabyroberts9601]

Thank you very much

[@almorkans3171]

Thanks Mentour. Learned something new today, viz how aviation deals with changing pressures during flight. An “ahhh, hah” moment. Now, as I mentioned on Chat, I would enjoy getting a explanation of the Flight Director. How does it interact with the Autopilot. Is it used in hand flying? When is it turned? An idea for a future video....?

[@CP140405]

I recall that the crew called "Transition" as we passed through Transition Altitude and it was then that we adjusted the altimeters to Standard Pressure... I don't remember setting Standard Pressure on the climb to whatever flight level.

[@maxmasur1145]

Hi fellow 737 pilot:) The question You asked is a little bit off I think. A much better definition where space begins and the atmosphere ends is given by T. Karman. He suggested that space begins at an altitude where an object has to go faster than the first orbital speed to maintain aerodynamic lift. So basically the edge of space is an altitude where you have to travel at orbital speed to maintain your altitude, no matter what shape your spacecraft is:)

[@tchevrier]

great explanation. At what point in a pilot's training are they taught how an altimeter works? Is it a standard part of all pilot training? The reason I ask is that I've had debates with many people who claim to be pilots who don't know how they work. Maybe the next video could be how the artificial horizon works? Again for this same group of people.

[@ianlivsey7200]

Thanks for that easy to follow explanation on QNH and flight levels. However, I was a bit surprised you didn't mention QFE. Could you please give some explanation of that?

[@petertucker7952]

QFE doesn't appear to be much used by airliners - as it indicates the height above a specific airfield, and airliners have radio-altimeters that indicate just that, when flying close to the ground. QNH indicates the altitude above sea-level, and is relevant when negociating nearby high ground, until the aircraft is high enough to regulate its flight by Flight Levels.

[@johnny_pilot]

QFE, for example, is used for aircraft doing patterns and touch & go's above the aerodrome's mean/nominal Field Elevation (useful for memory). It is only a local air pressure setting in hPa provided by the aerodrome and effectively (almost) zeros the altimeter when on the ground at that aerodrome... which could, for example, actually be 500 feet AMSL (above mean sea level). So, QFE is really useful when, for example, flying a runway pattern of 1,000 feet AGL above the runway (above ground level). It really has nothing to do with Flight Levels as you now understand, which is why he rightly omitted it for the purposes of this video.

[@Arcadiez]

QNH, the pressure altitude above/below sea level. The height that the airport is located in reference to the standard sea level. QFE the pressure where the altimeter reads zero feet at the airport. Even thought the airport may be situated on a mountain. QNE the standard pressure set (1013.25hpa, 28.82hg) at transition altitude. QNH is used all the time same goes for QNE however you say flight level instead. QFE is used by the military/military airports also on airport located for example on a very high mountain.

[@Stephanie-vt8xi]

Incredibly smart!

[@markc8434]

Terrific!

[@TonyP9279]

The Karmin line which is at 100 km.

[@MentourPilot]

Great! Check out the link to learn how to calculate it.

[@baljeep_gay]

karmen line*

[@robertbritton656]

hannes torstensson *Kármán.

[@I33nc3]

He is just a "fellow" Hungarian like "Láaszló Bíró", "Neumann János", "Teller Ede", "Puskás Tivadar" and the list goes on and on...

[@marinanjer4293]

It's Carmel line guys

[@alvarocifuentes6745]

Little Cessnas also have static ports outside?

[@MentourPilot]

Yes.

[@alvarocifuentes6745]

Okay, thanks!

[@avamendez1272]

Alvaro Cifuentes yes and a tiny propeller, if you time it right, it will defy the laws of gravity🛫

[@FlightDeckToGround]

I would be so grateful, if you do a video about performance of 737 or performance calculations. As always I hope, you are doing absolutly fantastic ;)

[@MentourPilot]

Thank you! I will see what I can do.

[@cortlandtatt6750]

If anyonee is looking for a great, greatest, humble & the best pilot instructor HERE ( METOR PILOT) because if you're going to school, the school is all about the money, in the some instructors are there for the 2 hrs by the time they get ready 1/2 hr passed, you learned 1 1/2 & some have attitude, too busy for questions or think they are it & yet you payed 400$. With mentor in 1 video you feel you're almost ready to fly. Mentor pilot may God be with you. Have always an awesome day

[@johnsullivan1307]

Nice video Mentour. Just wondering at Heathrow they broadcast QFE as well as QNH what is the different please.

[@petertucker7952]

If you set QFE on your altimeter it will give you your height above the runway. When you land, it will read zero, which is convenient. If you set QNH on your altimeter it will give you your height above sea-level and so when you land it will show the height of the runway above sea-level. So Heathrow caters for both options - whichever you prefer. I doubt if many, if any, aircraft do "circuits and bumps" at Heathrow, so if you are leaving the airfield using QNH will indicate the height that is more useful for terrain clearance, as maps show heights of hills and mountains above sea-level.

[@P991TS]

Riktigt lärorikt! Hade inte den blekaste👍🏻

[@evandickson19]

Very interesting

[@neetipaithankar5033]

Captain can you please explain when is QFE pressure set in the altimeter ? In this video you talked about the local QNH Setting I would like to know when is QFE used Thank you for such informative videos.

[@erich930]

QNH, as explained in the video, gives height above sea level. QFE will give height above the airfield. I know that sometimes military planes will use QFE for landing, but I don’t think there’s a scenario where a civilian plane will use it. Instrument procedures are written with height above sea level in mind, therefor commercial planes use QNH all the time. Then again, I don’t live in Europe, so I don’t really know!

[@shreyasjoshi5487]

Hi my answer to the question is approximately 99900 meters it should be a bit more than that as I used approximations like density of air=1 and pressure at earth's surface is 1 atm = 10^6 pa and g= 10 m/s^2 I used the formula P2-P1 = hdg Where P1 is pressure on earth's surface, P2 = 0,1% P1, h is height, d is density of air and g is gravitational acceleration.

[@MentourPilot]

Check out the link to see the correct answer! Good work

[@shreyasjoshi5487]

It's correct, well difference of 1 Km but that is because of approximations, thank you

[@haraialaremus3353]

Actually it is wrong... because density of the air depend of the altitude, and temperature also. That is why aircraft can`t reach edge of space. They can`t reach enough speed and in low density air they stall.

[@shreyasjoshi5487]

Haraiala Remus ok, you mean that I cannot take density as 1 because it is varying, correct ?

[@johnjohannson7143]

@@shreyasjoshi5487 when the air is too rarifyied the plane couldn't get enough lift to hold itself in the air. So it would stall* *(fall off the sky like a piano)