Compressor-Stall! Mentour Pilot explains.

hi everybody either a compliment or not video podcast as always I hope you're doing absolutely fantastic today on the video guys ken jet engines coughed hmm now sound like a very strange question but compressor stalls which is what we're going to be covering today it's kind of the way that jet engines cough okay it's a failure that is very very hard to diagnose it's quite hard to handle as well and I'm gonna give you four different things that you need to remember about compressor stalls so this video is brought to you together with audible now if you have made a new year's resolution to become a little bit smarter and to kind of you know satisfy your curiosity during the coming year but an audible is the thing to use and that's what I'm gonna use to listen to more books and if you use this link below or text the code mentor pilot to 500 500 if you're in the u.s. well then you get a 30 day free trial plus one audio book for free and two audible originals store Wow check it out and let me know what you think about it [Music] in order for you to understand what a compressor stall or engine surge actually is we're gonna have to go through four different steps so we're gonna start we're talking about what and how the jet engine actually works then we're gonna talk about what the failure actually is and then what causes it and how the pilots deal with it and as always there will be a quiz at mentor pilot calm at the end to make sure that you have paid attention so if we start with how the jet engines works now I'm just I'm not going to go through this and in any great detail but it's important for you to understand the kind of principles behind it in order for you to understand the failure so a modern jet engine tends to start a huge fan that's what you see when you're boarding the aircraft and that fan will give about two thirds of the Trust's that the engine produces by sucking in and pushing out large volumes of air at a reasonably low speed but if you go in a little bit closer and you look into the jet engine you will see that just behind the fan you have the compressor stage now the compressor stage start with an inlet guide vanes which is exactly what it sounds like it guides the air into the compressor and then you'll have varying stages of compressors and stators where the compressor are basically tiny little wings that and that sole purpose is to push the air backwards into the engine and the stator vanes are there to kind of guide the air to give a proper angle of attack to what's your next compressor stage so these compressors they keep pushing the air and making it you know more and more compressed until it is perfect it's kind of pressure to enter into the diffuser where we add fuel and then you have the igniters that ignites the fuel that releases an enormous amount of energy which is then being led out through the turbine stage now the turbines they harness some of that energy to drive the compressor stages and then the air gets pushed out to watch the back of the engine which also produces quite a lot of the thrust at the end in producers so this in theory and in very short terms is what the jet engine does now a compressor stall is just like the the name kind of suggests a stall of one or more of the compressor stages like I said in the beginning the since the compressor stages are basically a set of wings that is set up after each other with a nice perfect distance since there are wings it means that they could stall and if one of these compressor blades stalls or then it will affect the next compressor blade which will also stall and if it stalls it cannot do what it's designed to do which is to push the engine backwards so what can happen then is that pressure will very very quickly build up in front of it and it will also release pressure behind it so if a compressor stall happens it will happen in a matter of a second okay the stall will go from one blade to the other until all of the blades or part of the blades are stalled and an uncontrolled release of pressure will happen both towards the front of the engine and towards the back of the engine and this tends to happen simultaneously and the way that we will interpret this the what we the pilots will see and hear and feel is there is going to be potentially flames going up both in front of the engine and in the back of the engine that happens together with a large bang and if after that follows vibrations now depending on what kind of compressor stall you have you might have a single compressor stall in that case you will only hear that bang once and feel the vibration and then the engine will recover or if the reason for the compressor stall is still in the engine well then it will come back it will recover it become another bang and recover it become another bang and and this is what we refer to as engine pumping okay then you will hear have many of these happening at different intervals it depending on where you are so if you're at low altitude with high thrust setting there will be quite violent and if you're at high altitude at lower truss settings then these bangs would be more muffled and you might not feel the vibrations as much okay so together with that together with the actual feel and with the your tendency because obviously as the compressor stalls the engine we momentarily lose all its forward thrust capability so you will have a door you will have a bang you'll have vibrations you will also have indications on your engine display that will show in most cases a rapid increase in exhaust gas temperature in egt and that's because the flow of air to the engine has been interrupted and so there's nothing cooling the exhaust gas temperature anymore all right so these are the indications that we will get inside of the cockpit now this can come with a quite substantial startle effect right this is not something that the pilots are expecting it comes very suddenly it can be very very nasty and feel very bad and especially if this happens during the takeoff roll or even the initial part of the of the departure air traffic control will obviously see the flames shooting out of the engine and if they report that to the pilots the pilot might fall to interpret the what the what they're seeing as an engine fire so this is what I was talking about in the beginning of the video that it can be quite tricky to determine what it is and to actually diagnose the the compressor stall because of the bangs that you hear because of the yaw it can be interpreted as an engine failure which it is not at least not to begin with it can also be interpreted as an engine fire especially if traffic control or passengers are reporting flames to be seen but the problem is that it's not a continuous failure and what I mean by that is that we tend to train that the engine fails in which case you'll have the engine spooling down or severe damage to the engine we're just suddenly ceases but it's obvious when you look through the end in instrumentation that this is what's happened in the case of a compressor stall it's not as obvious because it can recover so you might have that sudden bang the egt arise the loss of trust but then it will recover back to normal indications and then it might happen again and every time that this happened an equal kind of startle effect will happen and there will be equally hard to control the aircraft so so how do we how do we deal with this done well the most important thing and what you have to remember when you if you're ever in a situation like this as a pilot is that you need to continue to fly the aircraft and you need to divide the rolls into the rolls that we train in the simulator so the pilot flying continues to control the aircraft which can be quite tricky because remember you have these kind of yours happening so every time that you have that compressor stall happening the aircraft we kind of lurch to one side which means that you need to put a bit of rod ring to counteract it and then it would recover itself so you need to take that rather way so handling the aircraft and continuing to fly it can be quite tricky on the other hand the polyp monitoring needs to be the one who is dealing with the non-normal checklist so in this case the first part is always to identify the failure which like I said can be tricky this might not be something that the pilots might have necessarily trained in the simulator it's also not continuous so you're looking at the answer mr. mutation when you're looking at it might look fine and then suddenly you get one of these surges happening so just to identify it can be hard and that's why in our quick reference handbook on the 737 we have a combined checklist which is called engine limit surge and stall so if we have identified it as a surge hold on it's the same checklist as an engine limit and that helps if for example the EDT is rising to up or above a limit that will lead us into the same checklist and the same memory items as if we decide see that it is an engine search an engine stall and what are the memory items done well memory items they are items in a checklist that we the pilots need to know by memory and the reason we need to know what my memory is because they need to be done fairly quickly in order to for example save an engine from breaking up all together in the case of an engine limit Serge stole the memory items are out of throttle disconnect and that's to keep the outer total from adding thrust to the engine then confirm which engine it is so that you're not dealing with the wrong engine and that engine the affected engine so the reason is as and not close is because you slowly slowly put pull back on the trust until the surging stops because remember depending on what has caused this it could be a it could be for example a bird strike that causes this so that something has been pushed into the compressor and that's what's causing the the surges to happen it could be icing inside of the engine or it could be a failure of one of the compressor stages another reason that it can happen could be a bleed air failure because remember I've talked about this in the previous episode about the bleed air system of the 737 the bleed air that's taken for de-icing the engine cowling or the wings and for pressurizing the aircraft and for temperature control is taken from the compressor stages from the fifth and the ninth stage if there is a sudden increase in bleed demand or a sudden decrease in needham on that might cause the angle of attack on these stages to increase which might cause a stall which it might be the reason so there are several reasons why an engine stall might occur but one of the ways to get rid of it is to reduce the trust on that engine so this is what parliment monitoring is doing as part of the memory items the engine is being pulled back slowly and when deserting stops then you can leave the trust over there and you might still have some usable trust from that engine alright so you closing it you're not shutting it down and in fact when the India has stabilized itself then you can actually start reapplying thrust on it if needed and if the engine search doesn't reappear we'll then you can continue to use the ending normally right now if that doesn't sort it out so you keep pulling the trust level back all the way until the trust ever is closed if it's still searching at that point well then you will go through the checklist and checklist will tell you to shut the engine down but you'll do that at a safe altitude where you still kind of control the aircraft away from terrain and so on right so why is this so important done well it goes back to what I was telling you before about the misidentification of this failure because if you miss identify this as an engine fire well then the engine fire memory items are very different they will actually cause you to immediately shut down that engine in order to preserve it and in order to to turn out a and to take out a potential fire and that will then of course leave you without the trust in that engine some trust that you might have had if you would have just done the memory items for engine limit search stall other famous examples of misidentification of failure like this is to actually identify it as being the wrong engine because because of the intermittent nature of the failure it's not obvious exactly what engine is causing the problems initially so a very famous example of where that happened was the the crash that happened outside of East Midlands Airport where a a 737-300 had problems with one engine surging but when they were identifying the failure the pilots were not they were quite new one type they were not too familiar with the new engine instrumentation and they because of different misunderstandings in the communication with the cabin they ended up shutting down the good engine so they were left with one engine they were searching and one end that were shot down this led them to a complete loss of trust which had the aircraft crash just short of the runway outside of East Midlands so it's very very very important that the pilot monitoring really looks at what the ending indications are and if he or she has any doubt discuss it with the Pala flying and leave the palette fly to fly the aircraft so that you don't both focus on this quite complicated problem and maybe end up you know not following the the procedure that you need to follow or flying in towards terrain or something like that so do take your time to identify this failure properly and then deal with it accordingly right so that's what an engine search or a compressor stall is now if you have more questions about this as always bring them in below in the comments and and also make sure that you have subscribed to the channel if you like these kind of videos and that you've kind of highlighted the notification bell a huge thank you goes to the sponsor of this episode which is audible now you know that I love listening to audiobooks to news shows to comedy shows I do that almost every time when I go to work when I travel in between the bases or when I go up instructing and even when I'm in my hotel room now a perfect tool to do that is audible and a book that I think that you will really enjoy listening to is the air crash detectives where you get to follow a female air crash investigator actually brings you through some of the most famous crashes in history and what the mythology is to kind of determine the causes behind the crashes it's really fascinating so if you use this link here below or if you're in the US and you text the code mentor pilot to 500 500 well then you'll get an absolutely free 30-day trial you get one audio book for free and two audible originals so check that out let me know what you think and before you go make sure you go to mentor pilot calm for your latest aviation news and also to take the quiz I have a link to the quiz here in the description and that will show whether or not you've actually paid attention during this episode so have an absolutely fantastic day me and Patti are gonna go out for a little walk and I'll see you next time bye-bye [Music] right guys I really hope that you like that if you want more content like that more radiation content but then check this out I hope that you have subscribed to the channel and that you've highlights little notification belt see you inside of the mentor aviation app and have an absolutely fantastic day bye-bye [Music] [Applause] [Music]

Channel: Mentour Pilot

Views: 121,274

Keywords: compressor stall on takeoff, compressor stall jet engine, compressor stall explained, engine surge on takeoff, mentour pilot 737 max, mentour pilot engine failure, Mentour Pilot, how a jet engine works, Jet engine, Compressor, nervous flyer tips, nervous flyers how to relax, nervous flyer video, nervous flyer help, Fear of flying, fear of flying help, Boeing 737, Boeing 787, Airbus 350, Airbus 380, Engine failure, how to become a pilot, pilot life, boeing 737 max

Id: 7MYh2KtEUQk

Length: 17min 32sec (1052 seconds)

Published: Fri Jan 24 2020