QNH, QFE and QNE - [Altitude, Height and Flight Levels explained]

qnh qfe aqne what is this and why it's so important let's jump right into it hi there i'm gabriele from parocline.com i'm a trainer captain on the boeing 737 and today i want to share with you all you need to know about this prefer reference this pressure reference is also called qnh qfe and qna before starting this video i want to ask you one question if you have any training pilot training related topic that you would like me to do a video just leave a comment below with your request and then i will consider your your message okay so let's jump right into it if you look at the whiteboard here before actually starting to talk about these pressure references i need to draw a sea level okay then a terrain a runway well it's not great i know but it's the best i can do and a mountain okay this is paramount in order to understand exactly the pressure references okay so what we've got here first of all the qnh what is a qnh qnh is the pressure at the mean c level so if i draw a line here this is the q and h okay is a pressure at the mean seal level what is a mean sea level as it says the mean sea level is the mean level of the sea because during the day and night it goes up and down so what they did they took an average eighth of the sea between the day and the night and that is exactly the mean sea level and the qnh is the pressure at the mean sea level but why is the qnh important the canadian spot is important because the pilot uses the qnh when they fly altitudes and most of the time the aircraft flies using altitude so if i draw an aircraft in here it looks more like a shoes but it's an aircraft i promise you so happen is that when the pilot used the qnh as a reference okay and the pilot can do that on the altimeters will fly following altitudes okay altitudes all right so then the qfe the qfe is the pressure around your airport around your field an easy way to remember is qf e you can use the the f because of the field okay so the qf e the field pressure so qfe is the pressure around the airport so this is the airplane is the pressure okay so an aqua flying at the same level if the pilots use the qfe as a reference we'll fly using eight okay so the altimeters will provide the eight from the qfe from the airport of your uh interest okay then we have the q and e the q and e is a standard pressure reference of 1013 ectopascal the q and e for this example let me draw the q and e in here here we go so q and e and this one zero one three point twenty five ectopascal okay and an aircraft using the qne as a reference will fly following flight levels okay flight levels so as you can see here three aircraft flying at the same flight uh sorry triac are flying at the same level will have a different uh vertical separation from the sea from the airfield from or from the q and e so an arc of using the reference the q and h will fly altitude and i kept using the qfe as a reference with fly 8 and an aircraft using the qne as a reference we fly flight levels all right so but when do we use qnh when do we use qfe and when do you use q and e all right let's start first with the qnh as you can see the qnh is the reference from the mincy level that gives you the altitude why it is important when you take off you always need to have the q and a set as a reference why because when you take off your law and your biggest right during the takeoff phase is that the rain since you need to know if you're flying below or above the terrain okay you need to use the qnh because the terrain elevation that you can find in the charts okay is the difference between the top of the mountain to the mean sea level so let's say that this mountain is at 2000 feet the top of this mountain is at 2000 feet so it's the difference between the mincy level and the top of the bond so if you want to know if you are flying above or below the top of the mountain you need to use the same references because if you use a different reference your altimeter provides you an information that is not useful for you fantastic then what is a q and e all right so as you can imagine the q and a is changing by place to place depending on the weather so a qnh in my area for example here that today maybe is one zero one thousand thirty ectopascal is different to the cure age of your area that maybe is one thousand so if we maintain the qnh our qnh as a reference and you're flying inbound me and i'm flying bound you what will happen is that once we get close we're gonna we are we're gonna use two different references two different altimeter pressure references because you've got your q and a as a reference and i've got my qnh as a reference and this is a problem because the separation between aircraft will be not possible so what what do we do once we fly so we take off we climb we get separated from the terrain so there is the terrain is no longer a factor and we arrive at a transition altitude once we pass the transition altitude we change our pressure altimeter setting from the qnh to the qne in order to get the separation from the other traffics okay so what will happen is that you will not use the mean sea level as a reference but you will use the q and e once the terrain is no longer a factor because you don't care anymore since the terrain you're flying well above the terrain but what you care is that during cruise you want to be separated from other aircraft that are approaching you and since everybody is using the same pressure reference the q and e during cruise we are safe that's our we are sure that our vertical separation is maintained okay that our altimeter is actually reading already in the same value because if you're approaching my aircraft and if i if if we are approaching ourselves and you've got the one zero one three set as a reference and i've got one zero one three said to my reference our altimeters are synchronized let's say okay fantastic lastly the qfe as we said is the field pressure and normally i've been flying for more than 15 years okay and i've never used the qfe the qfe you can use it if you want to know the eighth from the eight of your icar from your reference airport but the coffee is mostly used for maintenance uh when you're doing some checks on your altimeters you want to set the qf in order to check the accuracy of your altimeters all right i hope this video was clear for you if you took something out of it give it a like and consider subscribe to the channel in order that you don't miss the next videos also go to paloclime.com where you can subscribe for free parody training content if you have any questions about this video or any previous video just drop a comment below and i will answer you as soon as possible and i'll see you in the next one

Channel: PILOTCLIMB

Views: 35,248

Keywords: QNH, QFE, QNE, ALTITUDE, HEIGHT, FLIGHT LEVEL, ALTIMETER SETTING, PRESSURE REFERENCES, PILOT TRAINING, what is qnh, qfe, qne, qnh qfe

Id: 7rjL2CSiCvQ

Length: 7min 27sec (447 seconds)

Published: Wed Oct 21 2020