How are Jet-engines attached to the wings?!

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Why are jet engines fitted outside the wings and not embedded inside? In what way are they actually attached and what could cause them to detach from the wings?
In todays episode I will be discussing all of these questions and a few more. We will be talking about shear-pins, bolts and thrust links. I will also present two case-studies at the end where the system didn't work as it was supposed to.
If you have more questions on this, or any other aviation topic, let me know in the comments below. I love answering your questions!
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I want to send a huge "Thank You" to the channels featured in todays episode. Please use the following links to check out the full versions of the videos:
Mustard (The comet)
• Why You Wouldn't Want ...
WGN News (AA flight 191)
• Flight 191 crash, 40 y...
Aviation Accident clips (El AL 1862)
• Video

[@ivofodor6248]

I worked on rotating machinery in the petrochemical industry for 40 years. Large part of my activity was RCA (root cause analysis). One of the steps in an investigation was metallurgical investigation. The results of the metallurgical investigation would determine among other details whether the material of the damaged part was correctly selected, and had been correctly heat treated for its purpose (had correct hardness, tensile strength, etc.). Most important would be the determination of the fracture cause. Fatigue fractures do seldom occur suddenly, and have very characteristic surface appearance. The designers of the component that failed (your second case) have certainly been thoroughly calculated by the designers and dimensioned for fatigue safety. There must have been another reason (the root cause) why the component was exposed to additional forces or exposed to additional vibration which made it to fatigue faster than expected.

[@seccualfrustration]

“….and this might be interesting…” Sir. Every piece of content you produce has consisted entirely of intriguing substance. Much love

[@bikkies]

I loved the discussion about how the engines are designed to detach in a ground collision while maintaining as much structural integrity as possible. These steps all help to make an accident more survivable and the industry is right to pride itself on its record. One should never forget the terrible price paid by those that lost their lives in previous accidents, leading to the improvements and better safety we now enjoy. The industry must never ease up on its rigorous controls and we, the travelling public, should always pay attention to all advice and instructions from the cockpit and cabin crew.

[@samallan6616]

Back in the late 80's, an AA 727 flying to San Diego experienced an engine problem. The aircraft was over the Southwestern desert and the crew felt a thump, then got an indicator that the starboard engine had failed. They shut off the engine, started an early decent and simply flew the rest of the way to San Diego on the two remaining engines. When the plane landed in San Diego (without incident), it took the tower controllers to tell the astonished crew that they were missing an engine. It had apparently seized up and simply snapped off...exactly what it was supposed to do. They found the engine in the desert a couple of days later. There was a front-page photo in the local paper the next day of the plane sitting in the PSA hangar missing an engine. Good design worked that time!

[@bdawg7132]

Recognized the Mustard clip immediately. Easily one of the best channels on KZbin

[@barefootalien]

One other reason for the nacelles (pods) to be mounted so far forward of the wings rather than inside them is for aerodynamics. While the Comet _looked_ quite sleek, a modern airliner is actually quite a lot more aerodynamically efficient, and the placement of the engines is a big part of that. Why? Wave drag. Specifically trans-sonic wave drag. Even today in the age of efficiency over speed, airliners go fast enough that airflow over certain parts of them nears supersonic speeds. Without going into _too_ much detail (watch me now go into way too much detail, lol), right around Mach 1 (around 0.8 to 1.2 or so) is the most drag an aircraft will ever see. You have the normal drag, which is a combination of friction from the boundary layer between the airframe's skin and the air flowing over it, along with pressure drag caused by compression at the leading edges and evacuation at trailing edges, and induced drag caused as a consequence of extracting lift. At subsonic speeds less than Mach 0.8, these types of drag totally dominate the drag the aircraft experiences. At supersonic speeds, this changes. Sonic shockwaves form boundary layers of air that 'sticks' to the skin of the plane, taking up much of the skin drag. Those shockwaves also take on more and more aerodynamically ideal shapes, reducing pressure drag. And, the faster the plane goes, the less angle of attack is needed for level flight, and so the less induced drag there is. Instead, the formation of those shockwaves becomes the primary source of drag, as the supersonic flow (relative to the airframe) around the plane has to very rapidly accelerate to match speeds with the subsonic boundary layer of air "stuck" to the plane's skin. It does this at faster than the speed of sound, which is normally the speed any pressure wave moves in a fluid. In physics terms, what happens then is that the pressure in the trough of the shockwave just behind the wavefront becomes a vacuum, which takes enormous amounts of energy; energy that has to come from somewhere, and in fact comes out of the plane's kinetic energy. Just as an aside, at hypersonic speeds, more of the energy starts to go into thermal effects and phase change of the air from a gas to a plasma, and becomes the dominant form of drag at those speeds (which is what defines the difference between supersonic and hypersonic). In any case, short of hypersonic speeds (at which drag can theoretically tend toward infinity), the most drag a vehicle will ever experience is in the _transsonic_ regime, when both wave drag and traditional drag are in full effect simultaneously. This fact, combined with a lack of understanding of how to modify control surfaces for supersonic flight created what was known as the "sound barrier" in the early 20th century. Traditional streamlining, like what you see in the de Havilland Comet helps reduce traditional drag. To reduce _wave drag_ on the other hand, you use what's called the Area Rule. The minimum wave drag for a given overall flight volume is caused by the smoothest possible rate of change of the cross-sectional area of the airframe in the direction of travel. A big increase in cross-sectional area in a short distance along the length of the plane creates tons of wave drag, because it forms new shock fronts. In a traditional-configuration airplane, the biggest sudden increases in area (aside from at the nose) happen at the start of the wings, and the start of the engines. So for efficient flight in the trans-sonic or high-subsonic regime, you _do not want_ engines and wings to both start at the same point along the length of the airframe; that actually maximizes wave drag and greatly decreases fuel efficiency. Modern airliners are "waisted" subtly but (if you know what you're looking for) noticeably right around where the wings start to take shape, to reduce the rate of change of cross-sectional area. Having the engine nacelles well out in front of the leading edges of the wings helps further reduce the suddenness of that transition. The "hump" of the Boeing 747 where the upper deck is is also, in fact, entirely about reducing wave drag. The 747 has that hump for aerodynamic efficiency, and they got to put a second deck there, rather than the other way around like you might assume. It was a somewhat crude but _very_ effective design from an era in which the kind of waisting of the main fuselage we use today wasn't as feasible for structural integrity reasons. That hump, and the nacelles well forward of the leading edges, both revolutionary at the time, made the 747 the most efficient heavy aircraft for _decades._ As a neat little bit of trivia, wave drag is important for ships as well. The big, bulbous nose that extends out under the water in front of the bow of big ships designed for fuel efficiency (bulk freighters, tankers, cruise ships) actually deliberately induces waves that interfere destructively with the waves produced by the motion of the main hull through the water, greatly reducing the wake, the energy that goes into it, and the drag induced by it.

[@crowonthepowerlines]

"Human damage" is my new favorite euphemism for injury.

[@ClaptonFan91]

Gotta watch out for damaged humans

[@blessingchizema9154]

I HEARD HIM SAY THAT AND I WAS LIKE WHAAATTTT????? HE IS NOT A NATIVE ENGLISH SPEAKER...LETS FORGIVE HIM ON THAT ONE 🤣🤣🤣🙌🏾🙏🏾

[@michaelscott356]

Damage=Death in My mind.

[@BeigeAlertHamburg]

Personenschaden

[@C.Fecteau-AU-MJ13]

It would be a killer name for a band

[@MOOEYSMITH]

I saw one of these engines being tested at GE. It hung with two bolts on the engine and one (1) on the gantry (wing surrogate). I said what is the fitting on the plane. The engineer said "that's it." I said I would have expected more. He smiled and said "If your taking off and your engine hits a tree what would you rather rip off, your engine or your wings!!!" Good point.

[@mikeoxlong3504]

Mentour is an example of someone who started presenting videos in a reasonable way, as most folk do, and has now become so good at it, he is easily as good as a professional TV presenter! The transformation over the last four years or so has been extremely interesting to watch!

[@QuantumMechanic_88]

I've been a mechanical engineer for 40 years with an emphasis in aerospace engineering and machining . Can't wait to see more comments . Cool video and Thanks . Everyone stay healthy and Happy .

[@czhaok]

What does an 'emphasis' mean in this context? You either engineered aeroplane components, or you didn't..

[@QuantumMechanic_88]

@@czhaok Attend a university. Many courses have an emphasis to a particular area of expertise.

[@dimosfakiris8914]

To add a little to what @Mentour Pilot said. Since the two disasters he detailed, engine mounts are designed so that the front mount shears off first, and the aft shear pins break away last. This prevents the engine from coming over the wing and causing other structural damage to the aircraft such as damaged electrical or hydraulic lines.

[@zapatatapaz]

I appreciate your permanent positive standing, not trying to impress us as of how clever you are, but discussing THE SUBJECT and the positive consequences of these mishaps. (Francisco from Mexico)

[@susa88ify]

Hi Mentour, thanks for the awesome videos. Lot of clarity and details in your explanation. Respect! Could you please make some videos on the following topics? I would like to hear the answers from you. 1. Aircraft leasing 2. Lifespan of an aircraft and what happens after they retire a certain fleet 3. Some interesting details on technical rivalries between Boeing and Airbus (can be made as a series if possible). 4. History or evolution of airline companies as well as aircraft manufacturers in terms of technology, design, thought process etc (like a playlist / series). If anyone is interested in similar topics please like this. Thanks 😊

[@AdamBirty]

That 'positive attitude' T-shirt is epic!

[@LightTransformerGuy]

Was that the video or the shirt or both?

[@eivindkvinge6564]

Structural engineer here, I love the topic of this video. The tensile strength of 180 MPa is actually quite low for bolts, typical yield strength for steel bolts is 600-800 MPa. I am both amused and bothered by one specific incident related to the engine connection to the wing, that is the Hudson river landing. The amount of drag the engines produced must have been very high, I think one of the engines came off. Will increasing engine size on modern planes give less margin on keeping the plane level during accidental landings?

[@mytech6779]

Iconel 718 yield is about 160,000 psi, [1100MPa] I think he mixed units. Although he may have been quoting a high temperature strength as Iconel718 is often selected for high temperature uses.

[@mullity1952]

@Elvind Kvinge What is the shear strength of the bolt?

[@eivindkvinge6564]

@@mullity1952 yield strength x area / Square root (3)

[@sac3528]

"Accidental landings" This is my new euphemism for crashes.

[@Mike-oz4cv]

Yeah, his assumption of real world load was very optimistic (only 100kN in each direction (141kN combined)) and even then he was already at 1/5 of his assumed yield strength. Which would be very bad for metal fatigue (also considering that there is probably lots of vibrations and direction changes, it’s not just one nice, permanent static force). Your numbers make much more sense.

[@matyasgembala]

Mentour: I could spend hours talking to you about the technical bits of this. Everybody: Please do! Much appreciated!

[@michaela3274]

Me... (Notepad ready) - i'm listening

[@stephen_101]

That dog is absolutely adorable 🐕

[@darrens.4322]

Great presentation Peter. Thank you! On AA#191, I think it is important to discuss the improper de-mounting/mounting procedure the mechanics were using for the DC-10 engine, which was using a fork lift. I believe there was discussion that some vertical movement weakened fasteners leading to the catastrophic loss of AA#191. Other issues were the pilots did not get a stick-shaker nor stall warning due to losses in the electrical systems (generator) that the F/E had not been able to restore buses on. The pilots also received no slat-disagreement warning lights/gauge indicator, which also misled them, as they did not know they had an asymmetric slat/stall trend developing. The DC-10--Murphy's Law's favorite airplane: What can go wrong, will. The pilots of that ill fated flight did everything by the book, and in simulator presentations using the AA#191 profile, with pilots that did not know what caused #191 to lose control, I believe the great majority of those pilots in the SIM also lost control. As you said, one wing stalled, at a premature speed due to an uncommanded and unexpected leading edge devices (slats) retraction due to loss of hydraulic fluid/pressure.

[@antoninbesse795]

As we’re on the subject of shear, I notice that both Paxti and Petter have been to the shearers recently. Looking good.

[@jessicahao3185]

It’s amazing how well designed modern aircraft are. This is so obscure, they must have thought of everything. And it’s crazy that every single modern passenger aircraft has these features, all though they will probably never be used 99% of the time.

[@WyattsWorld22]

Your puppy moving at 3:15... adorable asf

[@donberning2086]

I was towing gliders the day after AA191 for an AA co-pilot who had invited his captain along to our small airport. I remember all of us pilots gathered around the desk looking at a grainy newspaper picture of AA191 on it's back. We were looking at the control surfaces and we could see the elevator pushed forward trying to unload but most important the rudder full right. We could see that the pilot knew he was spinning, more accurately snap rolling. To the end, their fellow AA pilot was flying the aircraft with proper control inputs to correct for a stalling left wing. What he didn't know was that no control inputs could overcome the loss of high lift leading edge slats resulting from the hydraulic failure. It was a sobering moment for all of us.

[@TheJoshRed]

Boeing PSD (Propulsion Systems Division) in the house!!! Thanks MP for all you do for the KZbin community!

[@jarekferenc1149]

Dear Mentour, another great and enlighting vid (as usual), but - sorry to say - the the Inconel 718 part (8:35) is messed up. The tensile strength of 180 N/mm2 (180 MPa) is exactly a half of a poor grade steel's strength - so this is a false information. Let me correct it: The only true info is 180. But this is in ksi (kilo pound per square inch), and is the ultimate tensile strength. 180 ksi is equal to 1240 MPa (quick conversion: 1 ksi = 1000 psi = 7 MPa). We never load the materials up to tensile strengh, the limit is the yield strength (when permanent deformation occurs). In the datasheet for Inconel 718, I've found the lowest yield strength of 52 ksi = 360 MPa. Then, if the diameter of a bolt is of 22 mm, then the force the bolt can withstand equals to 136 kN (the weight of almost 14 tons of mass).

[@juliettoler4123]

Great video! I love details like you have. I come from an aviation family; my dad was a RENI/Maintenance Crew Chief, I am a gate supervisor-lead agent and my son is an aviation mechanic, all with American Airlines. My son said you were spot on from his experience (his actual comment was "Holy cow, a pilot that actually knows what he's talking about! Not a bad compliment for him.) You may have a new fan. Anyway, I loved the video. You made it easy to understand. Keep 'me coming!

[@MentourPilot]

Ahhh, that’s like honey to my ears! Send him my regards and glad you liked it!

[@thomasm1964]

Petter, I have a question: I am always impressed by how much deep technical knowledge you have of the aircraft you fly. Is this actually a formal part of your training and job or is it a personal interest?

[@hafidz182]

I was about going to ask the same question.. do these kind of engineering and manufacturing details also being taught in flight school or certification?

[@MrFlyingPanda]

Both

[@mytech6779]

@@hafidz182 Much of this is taught in flight school. Not for all planes, only for the plane type that the pilot will be certified to fly. Not every engineering detail, the pilot would not be tested on specific alloy like "Iconel 718", but the pilot would be tested on the general electrical, hydraulic, and fuel systems design and operation. ie a 737-400 pilot would need to know that hydraulic system A is powered by two pumps one mechanical on engine#1 and the other electrical and powered from engine#2 alternator, and exactly which items are attached to hydraulic system A. They would also need to know the electrical layout(and power capacity) so faults can be isolated or power transferred from one subsystem to another in an emergency.

[@turbosubisandman7174]

After the El Al 747 crash, the attach lugs for the pylon were completely redesigned and made much more robust. Also the pins that attach the pylon to the wing are called "fuse pins". They are hollow bolts which are very carefully designed to break at an exact load. Good video

[@fredadam1950]

Great videos. Re: The tragic AA flight from ORD. "Forklift Joe" AA maintenance chief(later pres. of AirTran), decided to violate an engine change procedure using an overhead lift and use a forklift to do so. I flew the DC-10 with all of it's original design faults and fixes (after crashes, etc.) That the FAA permitted a "hydraulic lock" for the leading edge devices vs. and industry standard of a mechanical one as in all others, and the subsequent loss of lift when they retracted upon engine separation, nothing the pilots could have done to prevent this. The DC-10 was a great airplane to fly, but an engineering nightmare as it was slapped together to compete with the L-1011 trijet. The tailmounted engine, absent the "S" duct from the Boeing design, made it impossible for CAT III certification as go around thrust pushed the nose down.

[@cobra1010]

Cute dog noticing rolling hand movement at 10:50! :-D

[@globalautobahn1132]

Just ordered one of you Positive Attitude T-shirt’s! Particularly suitable during these difficult times! Love your channel! Keep up the great work and stay positive! 👍👍

[@rogerhorky7258]

It is easy to forget that for the first twenty-some years of jet airliners, cargo aircraft, and bombers, only the Americans placed engines on pylons on the wing. They're harder to design than is apparent. An aeronautical engineer once told me that pylon design was actually considered a secret for a while.

[@bradleycooke5214]

That was an excellent video. My question is - when a plane takes off and its wheels retract, is a brake applied to the wheels or are they left spinning? What are brakes made from, and how are they used during taxiing. More about taxiing - what are the procedures for applying thrust while taxiing, e.g., to advance the aircraft in a line to take off, to start from a stationary position, or when moving at a constant speed?

[@Richardincancale]

The overall technique is called a ‘mechanical fuse’, analogous to an electrical fuse - a deliberate weak point to protect the rest of the system.

[@QuantumMechanic_88]

Not quite ... but humorous .

[@ewilloch]

"predetermined breaking point" is the general phrase. In German, it's "Sollbruchstelle", which is actually a quite clever word which can loosely be translated to "The area of a part where the breakage is supposed to happen in the case of an overload of the part".

[@disorganizedorg]

A more every-day example would be snow-blower shear pins, which I consume at an alarming rate.

[@ewilloch]

Rich Marceau Sorry, but I had to laugh when reading that! 🤗😂

[@allangibson8494]

It was inherited from the earlier piston engined transports - literally losing an engine on the over water runs was very common, particularly due to a failed propeller or engine fire.

[@Boss_Tanaka]

Before watching this video: I m comfortable driving my car After watching this video : why is the engine inside the car?

[@y68on42]

So it doesn't crush you

[@HelloKittyFanMan.]

@@y68on42: He said "is."

[@HelloKittyFanMan.]

Boss, I'm trying to get your joke, but need your help. How, even in joking, did the engine get into the car (car's cab, I guess you meant)?

[@thomasm1964]

Hello Kitty Lover Man! No. He meant “Why is the engine not outside the car instead of being inside the bonnet (hood)?”

[@HappyHarryHardon]

I built some of the tooling platforms that hold the pylons for the 747-8 as it works its way down the assembly line.

[@cesareerasec]

I love the rolling dog 🐶😍😅

[@ahmadtheaviationlover1937]

Mentour pilot, you are an inspiration to me as a great aviator! I always look up to you as an example and will want to be a pilot as I have loved planes since the age of 4 and still do love them.

[@vishwanathank.s8214]

Well explained in a concise manner.

[@satyabratachakraborty675]

Very well explained along with the case study. Always love to hear such kind of exciting information from you. Keep it up Mentour.

[@Dirk-van-den-Berg]

I am a Dutchman, and I remember the El Al-cargoplane crashing into the apartmentbuilding in Amsterdam vividly. I was a student back then (1992) and I was visiting my parents on a Sundaynight when suddenly breaking news came about the crashing plane. I never heard the official results from the investigation, but I do know that our parliament conducted a legal inquiry that led a maintenance-engineer to plead the fifth, because he was made a bit of a scapegoat. So this is the first time since I hear what the issue was. Thank you!

[@tirthshah3288]

@mentour You including the case studies in the last few technical videos is a very good idea. It helps a lot in understanding the topic better. Very good idea indeed.

[@raymorley8241]

Great video. Mentour Puppy was as good as usual. Let's see a video on aircraft wing attachment. This is one area where videos of the process are hard to find.

[@rwbishop]

Back in A&P school c. 70's, they told us another reason for the forward slung under wing mountings was for additional wing 'flutter' mitigation. They also said some mounts were engineered to fail & let the engine fall free if subjected to excessive torque loads; as if an engines rotating element/s were to suddenly become 'locked up'... they said it would be preferable over possibly having catastrophic wing damage. Cool videos, Thanks!

[@mytech6779]

Flutter control would be extremely specific to each plane design. Engine placement would certainly have an effect but I feel that instructor was maybe over-extrapolating his information about one plane to all others.

[@get2dachoppa249]

I was also taught that when I was in A&P school in the late 80s.

[@lawrenceanderson6167]

I worked for FDNY EMS and I was a Paramedic in Rockaway Queens, NY when flight 387 went down in Belle Harbor Queens. The reason given for it going down was because the first officer had used to aggressive rudder control to recover from wake tubulance. My question is, why did the plane go into a spin where both engines ripped away from the plane? I would have thought that if the rudder ripped off, you would still have some control, using thrust rather then rudder

[@bwagenberg]

Beautiful animations. Love your technical topics.

[@anindyamukhopadhyay8]

Thanks 😊 for explaining in such a good manner. This content has answered many doubts in myself Thanks again 😊

[@cic5108]

Best videos of flying. Congratulations

[@bahman9]

The best channel in youtube

[@kwenaabrammosenye3487]

Compliments on the visuals and the content. They were key. I’m an aviation enthusiast so the visuals helped a lot. Keep paying attention to the small details, it makes the experience a whole lot better and it does set you apart👌🏾

[@walkingman9171]

Still remember AA191 very well, I was 18 and lived 5 miles south of the crash area. Very sad for the victim's and family's.

[@rwbishop]

A friend of my Mom lost her husband on that flight... didn't really know him but had been once introduced. Even then it hit a little close to home... shocking.

[@chilee6994]

The many many commerce and questions through the chart I've never been liked by anybody or by you.. no correspondence. Expected with a large audience. This was good content and I enjoyed it. Thanks

[@chadjo5403]

I slept during This explanation watching your house your red and green pillows and your beautiful dog !! 😀

[@user-ky6vw5up9m]

The EL AL incident was also when the public discovered that Depleted Uranium parts were used in the early Jumbo Jets.

[@ryanvandoren1519]

What?! I've never heard of this. Which parts of the plane was it used in?

[@horizonbrave1533]

I've been loving your videos mate! Do you think you could do a video of like a side by side comparision of some of the more popular engines and why they're so efficient?

[@simflier8298]

Thank you Mentour! Great explanation! Always wondered how strong those mounts were. They look so flimsy as the engines wobble and gyrate during mild turbulence.

[@skitka]

I always love your explanation and the puppies :-)

[@jeromehugh9624]

14:30 was a lesson learned moment that led to addition of side links r7r8 in engine pylon and design mod of fuse pins to avoid any notches.

[@wannamontana4130]

Here's a question: It seems that in both examples, that there were 2 factors. Loss of thrust causing yaw, and then flap retraction due to hydraulic failure. The answers posed, appear to address the first problem through structural answers. What about the second problem (the uneven loss of lift caused by the flap retraction)? It seems that evenness of retraction (balance of lift) is the highlighted issue. So is the plane better off with freezing them both evenly down, or having both sides come up together? Yes there are tradeoffs. Having both come up would be an easy default for loss of hydraulic pressure. However, the loss of lift for low-speed landings and take-offs would be a problem. Having both "pinned" in place down would have speed and range limitations. I'm wondering how the airline designers have addressed this 2nd problem mentioned.

[@get2dachoppa249]

Two changes came out of this accident in relation to your question. First, the FAA mandated that secondary flight control actuators (slats & flaps, basically) had to incorporate a mechanical locking feature to prevent uncommanded retraction from loss of hyd pressure. Secondly, there was a change to the aircraft operating procedures. The engine out procedure was changed from "slow down to xx airpseed" to "maintain present airspeed if possible". The pilots followed procedure for an engine out procedure, which included slowing down to a reference airspeed. That lower airspeed caused the left wing to stall because of the retracted slats. If the pilots had maintained their present airspeed during the initial climbout, the wing would not have stalled. Also related, after this accident, the FAA also mandated both pilot & co-pilot control columns have stall warning stick shakers. AA only had it installed on the pilots control column, and it became inop when the #1 elect system went off line when the engine detached, taking the #1 system generators with it. This was a well studied accident when I was in college for my aviation studies in the 80s.

[@michalholubek8157]

so good to see a video about different topic than crisis again 😁👍

[@jesussalmeron6374]

I have been a follower of this channel for several years and in my opinion this video is one of the most interesting that you have published. Thank you very much.

[@gracelandone]

Well done, sir. I have a personal connection to flight 191 out of Chicago and have done extensive research on that terrible event. It was a perfect storm of engineering failure, maintenance failure and training failure. It is almost never one thing that brings down an airliner. Your understanding and explanation of these events (explained in a straightforward yet caring way) brings confidence to those of us who are by nature or experience, nervous flyers. Thank you.

[@gracelandone]

Wow. I express just a bit of surprise at the number of cavalier responses regarding accidents related to engine separation from air craft conveying many passengers to their destination. In many cases, the destination turns out to be a horrid communal death. Y’all might apply just a modicum of empathy towards the victims and victims’ families of flights doomed by these accidents. You can be sure it hurts all around. I hope you never experience it.

[@Velo1010]

Modern engineering is very impressive. Thank you to all those that studied math, science, and engineering.

[@James-oo1yq]

Has the airline industry ever looked at a system to deliberately eject an engine in circumstances such as uncontrolled fire on an engine? Great work..love the channel and your content...and the Doggo! 👍🏻

[@SNOUPS4]

10:35 nice animations! It explains very well! Tack, Petter!

[@BRUXXUS]

I'm late with this comment so I doubt anyone will actually ever see it, but I'm curious about how many times engines have sheared off as intended and saved the plane from sustaining more damage. Has this method of engine attachment done more good than harm? I just discovered this channel. Really great stuff!

[@BonMyFY]

Cookie sheets and baking sheets are used interchangeably in recipes but there are differences. Both are rectangular, metal pans. Cookie sheets have one raised edge so cookies can slide off easily. Baking sheets have four raised edges, about an inch tall, and can be used for other purposes like roasting vegetables.

[@paymaker11]

Amazing, I just asked about the dc-10 crash in Chicago. You really have a great channel.

[@keithmiller2714]

Joe Sutter explains this really, really well in his book “747.” Great vid Mentour! Hope you get back to flying soon!

[@Stephanie-vt8xi]

Thank you for another video! I was a bit worried there when you said the engines weren't attached as firmly as the rest of the components; but it seems like they are fitted to deal with great forces. I find it interesting that the engines are also expected to shear off if they hit the ground to give the aircraft and passengers the best chance of survival. Are the bolts and shear pins now a part of regular maintenance checks between flights? How many bolts hold each wing on? how regularly are they checked?

[@major0eng]

Thankful to the engineers. Plus to what you said also wings wiggling and vibration

[@AdamTh1]

@3:15 NOTE: Adorable puppy doing calisthenics...

[@cck0728]

Excellent work. What does engine smoke color indicates? Black smoke and white smoke.... Thanks for sharing your valuable expertise.

[@johnfitzpatrick2469]

Thanks Petter, that was a terrific program, but I need to watch it again.

[@ChrisZoomER]

Thanks for this video, I’ve been searching for an answer to this question for years!

[@SKARTHIKSELVAN]

Thanks for putting efforts in making these videos.

[@orejustretherewithreonlyre2380]

A nother great video thanks petter :)👍

[@billbeyatte]

Excellent. Do more like this. Thanks.

[@davidsandell7833]

Very interesting video. I’ve often wondered why the engines weren’t incorporated into the wings myself. Just seems intuitively right.

[@OldManGaming69]

Good video. You must do a Rolls-Royce mount and explain failsafe links as well.

[@mysisterisannoying]

2:05 I believe the dog. Plus I didn't know that I knew so little about this topic! Thanks for the terrific content.

[@mauriciocastro7505]

Great chapter, aircraft structures strength and design are a pretty cool subject.

[@gauravladha5465]

Quite informative..Thank you

[@TaunusTV]

As always: very well explained ! 👍 My question is: what are the 2 little fins on the top left and right side of the engine casing ?

[@rwbishop]

They're 'Nacelle strakes'. Take a look at the Wikipedia 'Strake (aeronautics)' entry for an overview.

[@simplyaerospace1266]

Brilliant video Mentour

[@michaela3274]

I saw the accident of American 191 on Aircraft Investigation some years ago. In the vertical stabilizer there was a 'take-off camera' installed showing the taxi and take-off sequence to the passengers on board. Imagine the horror while getting a live video feed of the crash that will kill you...

[@FlorenceSlugcat]

Seems fun

[@mattesrocket]

That was the answer to the question I had the most often while flying in the last years and looking at the planes while boarding or flying. Very nice to know now.

[@flybywire5866]

That accident happened, because the airline cut corners to save money. They lifted the engines with a forklift, which cant be controlled precise enough. So they bumped the fixtures into each other damaging them. To my knowledge the plane had a novelty, a TV screen in the front of the cabin, connected to a camera showing what the pilots see. Imagine what the passengers saw. This is the kind of thing making me wary to fly. As a passenger i have to trust that things are done properly. Cutting cost wherever possible and safe operation are natural opposites. Nevertheless i have flown with a budget airline twice. Some years ago i flew with Germanwings from Düsseldorf to Paris. We were several hours late because the plane had technical issues. On the flight back we waited hours for the plane, which had technical issues and did not arrive in Paris because it didnt fly at all. They send us a pickup plane from Eurowings, a CRJ900, very nice plane by the way, really liked it. However, i felt uneasy when booking this weekend in Paris, but it was a package with the Germanwings flight. Two flights, one late due to technical problems, one didnt happen for the same reason. I thought they either have a defective plane or no plane at all. That was the last time i set foot into a budget airline. I wont do that again.

[@YobazlarDevri]

Great show to educate us

[@aaryesdee]

Very informative indeed Thanks

[@danielhedberg1158]

Så du får sitta i soffan igen👍🏻👍🏻😃 gött att du fortsätter mata ut intressanta videos👍🏻😃

[@ginggur17]

Yet again, I’d never thought of this. Perfect.

[@chrisno7495]

As always great informative video!

[@najjuzac]

Great detailing

[@hansparam]

Very informative. What i think the enginners should design a compact and strong rolling wheels below the engines and nose dome to facilitate emergency smooth landing during landing gear failures. It can also act as standby system.

[@speedbird9313]

Paramhans Baluni Landing gear failures are extremly rare..

[@lucas_k23]

Holy crap, you just keep producing and producing 😱

[@elimalinsky7069]

Covid-19 Not a lot of pilots are flying right now.

[@charlesjay8818]

desparate content, 17mins to tell people that the engine is attached by nuts and bolts, he must need the YT money lol

[@psisteak4122]

@@charlesjay8818 And you must be a desperate person to have to write comments like this over and over again ... Maybe you should spent some time learning English instead, your spelling is really horrible.

[@lucas_k23]

@@elimalinsky7069 Dude. I know. Obviously.

[@charlesjay8818]

@@psisteak4122 whats wrong with my spelling, i love trolls who comment on someones spelling rather than dealing with the content of the comment, Psi steak???? hahaha your as stupid as your name

[@grantrennie]

Thanks for the great video Petter 👍

[@camillejohnson7035]

Placing blame is very rarely part of any of your presentations. I certainly agree due to the fact it will not change the outcome. Moving forward to make changes is where your focus remains. Other agencies and companies do what they find necessary as a result. However, when the topic of replaceable parts comes into the discussion I listen carefully to hear if the part is the manufacturer part(s) or an off brand; and if it is a mechanical oversight. In this video the fate of this engine/loss of lives was difficulty to hear. But keep up the splendid work.

[@scidav87]

I like this one. Neat topic

[@Logarithm906]

I'm gonna call it. Bolts, plenty of Bolts, that can shear when forces are put into them the wrong way.

[@speedbird9313]

Eight..four fwd and four aft🤭

[@koen2062]

A330-200/300 with a GE CF6-80 has 9 bolts. Four on the AFT attach point and Five on the FWD attach point.😉

[@speedbird9313]

Je Moeder The MD-80 had three if I remember correctly🤭

[@QuantumMechanic_88]

Amusing .

[@mytech6779]

One of my cultivators has one shear bolt and one pivot bolt per shank, in the even it hits a large stone or stump. The other cultivator has one pivot bolt and two big springs per shank that automatically reset after the obstacle.

[@Quinine300mg]

I'm new today to this channel but this particular video brings back past memories of an AMT course I took a aeon ago in college. Those 8 special "jesus" bolts that hold the engine on were (correct me if I'm wrong) green magna fluxed bolts that we were told were very expensive and ultra strong having to take all those shear, tensile and rotational forces but were basically the only thing holding on 12,000lbs of engine. But then it also triggered a memory of a case study in which the maintenance technicians were using a forklift to do an engine swap out instead of the appropriate lifting device and damaging the pylon in the process which made me wonder if that was what happened in this vid.