Well, something's going on there. An experienced mechanic of jet engines just does not get close enough for such a disaster. Was it distraction, complacency (neither of which is likely around a JT8D at high power) or some other factor. Interesting story.

@AgentJayZ I use to work on B747 JT9D engines while running at idle. I would take off the core cowling then put the engine in reverse. That diverts the fan air forward. Great. No bypass air. No wind. Great for checking for air, fuel, or oil leaks.

@AgentJayZ My friend that got sucked into a jet engine was a mechanic. Running at high power is a routine maintenance procedure. He got just a bit too close to the inlet. Not much more of a story than that.

Your friend was where he should not have been. There is more to your story.

American Airline’s lost a disk on an high power maintenance run to check for vibrations. B767 LAX. The aircraft suffered a lot of fire damage.

@AgentJayZ Perhaps. I haven't been on your channel in 5-6 yrs tbh, so maybe was an old video. But I am pretty sure it was from my coworker who has been a site manager working on gas turbine power plants for many decades, both on new builds and rebuilding sites after accidents. He had some crazy stories (people closing a high voltage circuit-breaker out-of-phase, etc).

Yes, that was probably me that told you that.

Watch my video called So you want to work on jets...

That one is from ser #2052. Sadly, she didn't make it.

Thank you very much!

Even the SR-71 with every line curve and dent that could reflect radar back to a station and get it shot down was shaped and made with a slide rule! Seriously one mistake on the bottom of that plane and it would light up on radars like a christmas tree. Yet it was done with a slide rule.

@Graham Haynes Fair enough. Lots of lessons in engineering/test history have been learned through injury/loss of life. Glad this one wasn't! Hope you have a good day! :)

@EpicSpaceTroll 139 It happened in the 1970's. A lot of lessons have been learned since then.

Wow that's scary! Glad the operator made it. I wonder, why wasn't the window already armored? Or was it armored, just not for large pieces of turbine disk?

@AgentJayZ Ah! I see, thanks for the explanation.

The greater the difference in speed between the propellant gas stream and the flight speed of the aircraft, the more energy is wasted on the turbulent mixing of the gas stream with the atmosphere.

The manual will list boroscope locations. Any competent A&P tech with experience on the CJ-610 is worth a couple hundred bucks an hour to talk to about this, and to hire to perform the inspection. Any Competent A&P tech without experience on the CJ-610 is worth150 an hour...

1 - there are warnings about throttle control in the old jets, in the pilots manual. The rest of your comment is not true. The DC-10 had the CF6-6, and it would respond nicely to having the throttles instantly moved to 100%. No sweat. Any modern engine will do that. There are other reasons why airline pilots never so that. Even Concorde would never apply full power right at a standstill, but ease into it after moving forward some distance. The FADEC in modern engines performs the same duties as the FCU on the older ones. It does a much better job at it.

As explained before, no. Also, a turbine is an assembly of many blades in a disc. Discs can fail, and blades can break, but there is no such thing as "breaking a turbine". It's too vague.

@AgentJayZ So essentially they will use the casing and stuff it full of new parts. I would not want a job like you perform in a rebuild like that. Too many judgement calls based in part on the experience of the mechanic. @grahamj9101 I wonder what modifications were made to the Trent FOHE? Care to guess? Jay and I discussed those stub pipes. Regardless of fault, they had no business being on those engines. As for the water landing, I think we can safely assume a Canada goose does not offer most appropriate fluid medium for most if not all turbine engines.

And they just grounded 24 777s. And... "Boeing released its own statement late Sunday, saying it recommended suspending the operation of every 777 that uses the Pratt & Whitney engines. It added 69 are currently in-service and 59 are in storage." Houston, we have a fan blade issue.

@grahamj9101 Thanks very much for the info and links! Some light reading for me tomorrow. I must be a bit demented. Metallurgy fascinates me. I blame it on my boss who once took a 30-06 barrel up to R 65 and fired it (remotely). Very very gnarly mess but interesting how the pieces revealed an assortment of stress characteristics.

@Sheila Walker I found the clip to which you refer and, yes, it does appears that there are portions of two blades missing. Where they went, I wouldn't like to guess: I'll wait for the NTSB report, as we all should. I will acknowledge that the Air Asia A330, to which I referred, was in cruise when it lost a fan blade, as it was about an hour out of Perth, Western Australia. If you check the ATSB report, you will find that about three-quarters of a fan blade was missing. In comparison, United flight 328 was reported to be at around 13,000ft, which looked about right from the video clips of the aircraft, the puff of smoke and the falling debris. Consequently, compared to the Trent 700 failure, the fan speed and the energy levels of the blade release in that PW 4000 would have been somewhat higher. I am, nevertheless, perturbed by the gross loss of engine cowling panels, and the apparent disruption of something that fed the fire. The Trent 700 does appear to have been somewhat more robust in this respect. In terms of what might and might not be re-used from that engine, while it will be stripped and minutely examined, my guess is that much of the fan, fan booster and HP compressor sections will end up in the scrap bin. The fan casing and the static structure around the front bearing housing, in particular, will have taken a considerable amount of damage. The design philosophy with which I am familiar is that, in the event of a fan blade off, the FBH support structure is actually designed to fail at a structural 'fuse', to allow the unbalanced fan rotor to rotate about its new centre of mass. The NTSB report will tell us how much damage there is in the engine, and it will make interesting reading. Did you ever read the report on the engines from US Airways flight 1549, or the ATSB report on the engine from QF32? And the AAIB report on the investigation into flight BA38, which crash-landed at LHR, was fascinating - for an engineer.

Sheila, wherever that engine ends up, it will be disassembled to the last nut and washer. The big pieces will be inspected dimensionally for plastic deformation due to the monstrous forces they endured. If they are out of spec, they will be destroyed. If not, they will be inspected for cracks. If any are found that are outside the repair schemes, they will be scrapped. Then, millions of dollars of new parts will be used to reassemble the engine into zero timed overhauled condition. It will be identical to a new engine.

@grahamj9101 Just what Boeing needs following the 737 Max debacle; 5632 fan blades heading for the lab. This recent incident did have an excursion, whether principle incident or secondary is academic at this point. It is going to be interesting what corporate wriggling and wheeling and dealing comes down with the 777X coming on very strong and GE and RR newest engines strolling passed the competition.

The difference between Rolls Royce and P&W apart from quality is the inlet ring on the 777 and P&W engines in general . The RR engines have a much deep inlet that contains compressor blades flying off . The last 777 blade actually struck the fuselage as it cut the inlet ring off on it way . This is classified as an uncontained failure as internal engine parts were allowed outside the nacelle . Its disastrous for P&W as these blades are pretty low tech when compared to the latest RR multi pitch and angle Ultra Fan types . I'm guessing you that we may see much deeper inlet rings as a result .

@AgentJayZ In this video: kgkey.info/block/0Xd6oNGPkLGXpG0/video.html it looks to me as if one and a half blades are missing if you go frame-by-frame. Maybe one broke off at the root, and it took half of another one with it, as sometimes can be seen in the certification blade-off tests.

@AgentJayZ Sorry, AgentJayZ: it ain't necessarily so. In 2017, a Trent 700 engine on an Air Asia A330 lost a fan blade. The engine cowling remained intact. There are video clips elsewhere on KGkey, which show the failed engine shaking away on the wing, much like the engine on the United B.777. There are also clips of the cabin, showing the passengers being shaken, "like sitting on a washing machine", which they had to endure for two hours.

Hmmm, your eyes must be better. I watched the clip several times and could not see that. It would explain the shaking. If even half a fan blade "departed" at climbout power, the violence of the shaking would cause the cowling to be ripped to pieces.

A J57 on your wing? What, you got seven more to carry you through... Or are you flying an Americanized Canberra?

That will be happening soon. I have watched the same clip you have seen, but I think I might wait until Blancolirio supplies us with a few more details.

That's the subject of an upcoming vid. Stay tuned!

The Progress D-18T turbofan engine of the An-124 has also seen two uncontained failures last year, one in March 2020 with no details known other than that it was traced to the second-stage disk of the intermediate pressure compressor, and the more publicized fan disk failure in November

In 2010, the No.2 Trent engine of Qantas flight QF32 had an uncontained failure of its IP turbine disc (it's discussed elsewhere here). This was not because of any defect in the disc, but was as a result of a raging oil fire that grossly overheated the drive arm of the disc, which then twisted itself off the turbine shaft. The IP turbine was then driven to overspeed and burst in around 120 miliseconds. There are no casings on any jet engines flying that will resist a major disc failure, whether compressor or turbine. As I've mentioned elsewhere, there were uncontained failures of both fan and HP turbine discs in the early days of the RB211 on Tristars - and to maintain some balance, there have been similar failures on engines of US origin. Fortunately, such failures are extremely rare.

@Dan Lemke I was fairly sure that I'd come across references to the B-52 using water injection on take off, and old film clips certainly showed them producing far more smoke than can be seen with the current model. I've checked with Wikipedia, which tells me that the early marks with J57s used water injection for take-off, fed from a 360 gallon tank in the rear fuselage.

@grahamj9101 The KC-135 tanker also used water injection to get the heavy loads in the air. The biggest difference I noticed was the noise! They didn't seem to make much more exhaust smoke. The Buffs didn't have water injection that I was aware of and like the F-4, they just burned a lot of fuel and oil to make the blue smoke that actually made them easier to target. It was the engine itself that was the issue, not water injection. Most probably don't know, but jets require synthetic oils to run due to heat, and they use quite a bit of it, at least the older jets I worked on did.

@grahamj9101 There is a gas turbine lying on the road, and I am making a video of it, this one since 1980 and it is a J 32 allison, with 14 combustion chamber, single stage sentrifugal compressor

@Al Smith An otherwise undamaged disc, whether a compressor or a turbine disc, will fail in overspeed, to produce three 120degree segments. A failure resulting from an incipient flaw in the disc is more likely to produce multiple pieces of debris. During my career, I saw numerous photos of discs that had been failed on an overspeed test in a spin pit, to produce three segments. That is essentially what happened to the IP turbine disc of the No.2 Trent engine on QF32. One segment of the disc was found on the island of Batam, only hours after the event. Having seen a photo of it, I immediately set down my hypothesis of the root cause of the failure, which was subsequently shown to be essentially correct. However, there is also plenty of high energy 'shrapnel', which is produced as a result of the initial failure, including released turbine blades and chunks of the turbine casing. Those small holes in the wing could only have been produced by 'shrapnel'. A380 'Nancy Bird Walton' and its passengers were extremely lucky, in that the trajectory of none of the three disc segments went through the fuselage. But then so were the passengers on some early Tristar flights, when RB211 engines experienced uncontained failures of fan and HP turbine discs. Not so lucky were the passengers on the DC10 flight that came down at Sioux City in 1989. Fortunately, such events are extremely rare, and becoming rarer.

@EL GRAN LEON Water injection permits an increase in thrust, without an excessive increase in turbine entry temperature, for a short period, on take-off. Its function is to provide a cooling effect on the combustion products, a by-product of which may be the production of smoke, to a greater or lesser degree. B-52s had it, which is why they produced so much smoke on take-off in those old film clips. BAC 1-11 airliners also had it and Harrier jump jets still have it. If you see a clip of a Harrier performing a vertical take-off, with visible smoke coming from the 'hot' nozzles, it will be using water injection. Operationally, it should normally be used for a 'short lift wet' take-off rating, with a maximum load of stores, when performing a rolling take-off, with partially deflected nozzles. My recollection is that the Harrier carried enough water/methanol for a maximum of 90 seconds usage.

He never proposed walking around it while at rated power did he? Or did I miss something?

Wrong question. Would I feel safe testing a freshly overhauled CFM56 turbofan? Yes. We could "what if" to the back side of infinity. Not doing that. Too busy living in the world...

@Ben I Some engines also have a mechanical shut off, in the event of an LP turbine failure. The Olympus 593 did and so did one mark of the Trent.

Awesome thanks Graham! Thanks for the for the clarity. I should have been explicit... Jay would not approve. I did mean blade failure for the casing. Of course the idea being that anything escaping goes out the back in the exhaust flow. Disks can't be contained physically. The software is designed to sense when they are approaching dangerous speeds and shut the fuel flow off to prevent the burst in the first place.

There are no casings on any engines flying today that can contain the total failure of a disc, whether that of a fan, compressor or turbine disc. The design philosophy is to make such an event extremely improbable, through careful design, rigorous control of manufacture and extensive testing. If engines had containment shields capable of containing such a failure, they would be incapable of flying, as they would be far too heavy. In fact, it would be impossible to come up with a sensible design. However, there are engines out there that, in certain cases, have containment shields intended to contain multiple blade failures. And, of course, the big turbofans have containment features, such as Kevlar, around their fan casings, which are designed to contain the release of a single fan blade. You may be interested to know that the last mark of the Pegasus engine in the Harrier jump jet, has an Armco containment ring fitted into the aluminium casing above the first stage of the three-stage fan. This is designed to contain the release of the portion of a single blade from above the snubber (aka mid-span shroud in N America). The engine would fail, of course, but the design intent is to prevent major damage to the airframe, including a fuel tank, and give the pilot enough time to eject.

Also an important point for the Jay's test cell is that not only does the J79 WAY predate the containment requirements... And in its flight version it was a military engine which has different standards. But the cowling on a modern turbine is also part of the containment system. This is why test cells for commercial engines use the same principles as this cell, the turbine is offset from the control window. They also tend to have much thicker walls and glass... But I believe this is more the volume of testing they need to do in commercial engines and the desire to have the test team not needing hearing protection. The bigger cells at major airports also tend to be sound proofed so you can test your average commercial engine and make no more noise than a vacuum cleaner. This allows them to use the cell 24hrs a day as there is virtually no external noise. Of course it's easier to sound proof when you don't need to test afterburning engines!

@AgentJayZ I Meant during the Extreme Engine Water ingestion test where they Dump Hundreds of gallons into an engine

@AgentJayZ In the limit, I believe it is possible that a turbojet could be made to flame out as a result of an extreme water ingestion event - and I think it may have actually happened in flight, in the dim and distant past. I have previously told the story of the Proteus turboprop in the Bristol Britannia, which suffered flame-outs during test flights in unusual icing conditions over Africa (I think it was), in the early 1950s. If you find a cross-sectional GA of the engine, you will see that it has a reverse-flow arrangement and a radial air intake, similar to that of the P&W PT6 engine. This arrangement resulted in a long inlet duct around the engine, with a 180degree turn of the air forward into the compressor. It was discovered, the hard way during flight tests, that under certain conditions, ice would build up in the intake and large lumps would drop off, to be harmlessly 'minced' by the compressor. However, the combustors didn't like the experience of a large amount of water suddenly being delivered to them and they flamed out. It was soon established that the icing phenomenon only occurred occasionally under predictable atmospheric conditions, and that it only needed the igniters to be switched on to alleviate the problem, with no more than a momentary loss of power. Nevertheless, BOAC, the prime customer for the aircraft, demanded that an anti-icing solution for the intake be developed and tested, which delayed EIS by two years and the loss of sales to other airlines.

You need to clarify what you mean by "water" ... what amount. All of it will go through the core of a turbojet, but no naturally occurring amount of rain will impair the function of the engine. The heaviest rainfall in the world: a turbojet does not care.

1 power turbine 2 reduction gearbox 3 the main fuel control is quite sophisticated.

AgentJayZ is asjcs explanation correct? Honest question not trying to troll

EGP: what you see or don't see, and what you understand or don't understand... is irrelevant. It does not make this an argument or a debate. it means you need to learn how the world works, so get to it.

@Glenn Edward Pace The total mass doesn't matter. What matters is the mass of each rotating disk, and that is higher in the turbines. If you have 10 rotating disks weighing 50 kg each (not that a jet is like that - each stage is different), connected rigidly to 2 disks weighing 100 kg each, which is under more stress? The heavier disks are, even if the total assembly mass is lighter. The blades themselves are also much lighter in the compressor. They are very thin, almost like knives. Turbine blades are "fat", and are often made of heavier metals than early compressor stages. Also, when a turbine bursts it isn't just the blades that come loose, it's a burst of the entire disk, usually into three 120 degree segments, and as a turbine disk is much heavier than a compressor disk, these segments contain more energy. The huge temperature difference also makes it less likely for a compressor to burst.

ASJC27 the compressor is probably heavier due to it having so many stages. I don’t see why a blade coming loose in the compressor is any less dangerous than in the turbine

@Glenn Edward Pace Heavier rotors, high temperatures.

@AgentJayZ I mean I did search around but I dont really know what to search for... If I search for scrap I get complete engines, if I search for parts I get new parts, and if I search for "scrap parts" I get recycled parts... So no I did put forth effort... I'm just not a jet engine technician, so I don't know what I'm doing/looking for...

Yes, there is a huge aftermarket for spares and scrap. The fact that you didn't know that means you have put zero effort into your search so far. My assistance to you has come to an end.

no it's P=M*V 😂😂

@orcasea59 momentum = M*V^2

@AgentJayZ Thanks, that makes sense. F = M*V. I should have remembered that!

It's all just a lot heavier. A compressor disc weighs about 10 lbs, and has about that much in blades attached to it. A turbine disc is ten times as thick. It weighs over a hundred lbs, and has about 50lbs in blading attached. Going five hundred mph, a garbage can lid is going to really damage a car. A manhole cover is going to go right through ten cars in a row. Sorta like that.

Have I told you, Sheila, just how much I love you? I will!

Oh, you bet, Dozer !

​@AgentJayZ Thanks for the response.... yep I was thinking the cradle in your older videos looks like it can pivot, which would be more suitable for load cell measurements. Once an engineer always an engineer I guess.Thanks again!

Yes, we built a thrust test stand years ago for the J79. It is actually easier to use than this old clunker, which it replaced. I don't know why the crew used this mount, and I didn't ask. The usual, and correct one has a pivoting cradle, to which the engine is attached. The cradle transfers the thrust through piezoelectric links to the rigid anchor. Here, they have used the old anchor to hold the engine directly.

It's like the opposite of a trebuchet :-)

@AgentJayZ Modern EFI is also a closed-loop system. The loop is closed around the reading of the lambda sensor, i.e. it actively adjusts the amount of fuel injection to reach a desired air-fuel ratio.

@AgentJayZ thank You!

Fuel is pumped in until the fuel control is happy. It monitors EGT, RPM, and power level requested. Unlike EFI in a car, it is a closed loop system. Amount of fuel flowing is measured as a convenience to allow the crew to calculate what they have left.

@AgentJayZ interesting, thanks. Fuel metered by weight?

There is an inlet air temp sensor, but fuel temp does not matter.

The individual compressor blades are much lighter in mass and material than the turbines. Less rotational mass is less energy at the same speed. And lower inertial mass is easier to stop.

@Atle Olav Dahl Yes and thank you I found a video with the correct spelling kgkey.info/block/wH-tpqq2brp5uZg/video.html

Probably Kongsberg. Made by A division of Kongsberg Våpenfabrikk in Kongsberg, Norway. Acquired by Dresser-Rand in 1987. Rumor has it that they used air-cooled VW Beetle engines as starting engines when testing the the turbines, and at least once the mechanism that was supposed to automatically disconnect the VW engine from the gas turbine as it revved up failed.

It sounds extremely dangerous... but it's not.

Yeah, that's why no dumbasses are allowed at the test cell.

The plane of rotation is already far away from the control booth. Did you watch the video where I explained that? Put your helmet on, and eat your paste... downstairs, in the corner, with the lights off.

@AgentJayZ Just to get the line of rotation more away from booth. I know it was mentioned it is rare for anything to explode, any little thing could prevent a potential event. Thx for your videos!

What for?

Years ago, when I was racing bikes, we would race at night at a little track that also held stock car races on the same night. A car crew chief wanders through the pits, over to my buddy who rides a Yamaha R6 with a screaming open exhaust collector. Chief says "What the heck is the redline on that thing?" Jed says "Fifteen five" Chief: " What do you shift at?" Jed: "Fifteen five!" ... I am still smiling at that exchange between the car world and the bike world.

Just down the road from where I grew up :)

Absolutely. Best description ever... especially for our current times !!!

No. It was a piece of the nacelle that hit the window. That's airplane parts, not engine.

I think I may have to make a video about that, because I've explained it too many times. We use the same engine protection from FOD you will find at every airport in the entire world. Every last one.

Eventually they came up with a screen.

The propane is heated to about 100C. The fuel nozzles used can be seen in my videos called Jet Fuel Nozzles

Jet engines used in airplanes don't run on propane or natural gas. They run on jet fuel, which is basically liquid kerosene. In some cases turbine engines are converted for industrial use and they do burn natural gas instead of jet fuel. In any case the compressor discharge pressure and the discharge pressure of the fuel supply (using either liquid or gaseous fuel) must be higher than the pressure inside the combustion section so as to maintain positive flow going into the combustors.

@AgentJayZ LOL!!

Why that's a compliment, sir! We don't actually handle compliments here. That's across the hall...

Looks the connections for a three phase starter/alternator

Whoopsiedoodle

Ouch

Wow. That's a hell of an expensive ladder!

@AgentJayZ So we just need all of your subscribers to pitch in a few bucks and we get to see what FOD damage looks like. I have a high speed camera that I use for lightning research... I'm more than happy to lend it if the money gets raised!

@AgentJayZ well I guess im buying lotto tickets and if I win your going to run the worlds most powerful blender lol

The test cell charges a 20K fee. It takes three techs a day to install the engine and get it ready to run. We would need about a hundred gallons of fuel You supply the engine You put up a bond to cover any damage to the test cell. You need to give me some incentive i.e. why am I doing this? Another day do get it out of the cell. However long it takes to clean up any mess and or damage. So as a rough guess, a half mil oughta cover it. So that's why we don't play around like that.