5 ms·

I thought it was 'confined' if the containment ring did its job? If it had failed (like not supposed to) it would have been a whole lot worse.

by hazeii 6y ago

colechristensen 6y ago
The plane landed and didn’t blast enormous holes with ejected compressor blades. That’s a successful failure.
- underseacables 6y ago
  Is that what happenes when The fan blades fly off and hit the airplane?
  - kyshoc 6y ago
    That’s almost exactly what happened on Southwest 1380[0] a few years ago. [0]: https://en.wikipedia.org/wiki/Southwest_Airlines_Flight_1380 https://en.wikipedia.org/wiki/Southwest_Airlines_Flight_1380
  - hazeii 6y ago
    As ever, more detail and clear explanations on pprune[0]. As one commenter put it, to an ER doctor this is a shallow wound with lots of blood. [0] https://www.pprune.org/rumours-news/638797-united-b777-uncontained-engine-failure.html https://www.pprune.org/rumours-news/638797-united-b777-uncon...
  - colechristensen 6y ago
    Pieces on the inside of jet engines are spinning between 2,000 and 12,000 rpm. They should all be properly contained in an airliner, but before that was the case of one fan blade broke and hit the plane it could look like a bomb blew an enormous hole in the side of the plane. These small pieces have a huge kinetic energy because they’re spinning so fast. Nothing bad happening, everyone uninjured and a plane making an orderly airport emergency landing is many layers of safety systems all working properly.
    - dredmorbius 6y ago
      Hull penetration at altitude can lead to explosive decompression, and, depending on the specifics of the penetration, complete hull loss. Airplanes are big fragile inflated sausages, and it takes relatively little by way of explosive to down one. An early model (the de Havilland Comet, operated by BOAC and South African Airways in the 1950s) was downed due to a design flaw leading to metal fatigue around the windows, with three aircraft lost in 12 months due to in-flight break-ups, 99 souls lost. Even at lower altitudes, an uncontained fan or turbine failure can be rough on the cargo or passengers, either from direct shrapnel, decompression, or (partial or full) egress. https://www.bbc.com/news/world-us-canada-43803340 https://www.bbc.com/news/world-us-canada-43803340
  - touisteur 6y ago
    Ugh look up QF-72 for an A380 Rolls-Royce engine containment failure...
    - mcdevilkiller 6y ago
      Are you sure? That was an A330, and a failure on one ADIRU.
      - touisteur 6y ago
        Aaaaaah always mixing this and QF-32 :-( sorry. The book by Richard de Crespigny is a must read if you can find it. Great.
    - martyvis 6y ago
      QF-32. (BTW the pilot Richard Champion de Crespigny wrote a fantastic book on the incident. The intensity of going though procedures on an iPad and manuals as alarms were going off, while remembering to just fly the plane, was the thing that most sticks in my mind.
      - touisteur 6y ago
        Sorry, right, always mixing up those two. Best lessons from the book for me are: 1- meet the designers, understand the "why"s and not only the descriptive posthoc documentation 2- when you don't trust your instruments, keep following the procedures, checklists, (for this you need an excellent, trained, cold-headed team), and eventually try to reconstruct 'what aircraft you have' 3- trust the automated checklists but not too much! Crosscheck what's asked of you, with what you know of the aircraft. Since you know the 'why's you know the automated checklist system's designers probably never expected an aircraft with that much damage to keep flying... 4- there are no hall-passes for heroes. At the end De Crespigny fails his evaluation (the flight was an evaluation flight, with an instructor on board). All around a great, great book for systems people.
  - lm28469 6y ago
    Most of the "skin" of a plane is only a few mm thick [0] it doesn't take much to puncture, I mean, it does, but thin turbine blades made to resist birds impact at 10k rpm would cut through it like butter. [0] https://aviation.stackexchange.com/questions/45566/how-thick-is-the-skin-of-an-aircraft-like-the-airbus-a350-or-boeing-b777 https://aviation.stackexchange.com/questions/45566/how-thick...
  - benhurmarcel 6y ago
    To add to the topic, aircraft structure and systems are made to withstand the projection of those debris hitting with "infitite" energy. That means for every trajectory possible, it's considered that a part flies through everything in its path. The aircraft still has to land.
    - o-__-o 6y ago
      The wing is an exceptionally strong component of the aircraft. It’s usually the freak accidents where you hear of a fuel tank being ruptured or control or hydraulic lines being cut. In all of these accidents I bet there is wing damage but the plane is able to continue as usual WW2 fighter planes anyone?
- hazeii 6y ago
  Plenty of youtube videos of a blade-off test - here's a short one [0] of an A380 Rolls Royce engine testing. That's about £9,000,000 of engine being destroyed in this (successful) test. [0] https://www.youtube.com/watch?v=5-8_Gnbp2JA https://www.youtube.com/watch?v=5-8_Gnbp2JA
  - dtgriscom 6y ago
    At the beginning of the video the blades seem to be spinning at about 2RPS, but after the explosion they're spinning much faster. I presume the former was an artifact of the camera's frame rate.
    - hazeii 6y ago
      They normally have high-speed cameras running; that short video is a mish-mash of super-slow-mo and regular speed footage. There are much longer versions on YT, e.g. this one [0] which covers it in more detail (watch the people in the room jump when it blows - despite being a fair distance away). [0] https://www.youtube.com/watch?v=j973645y5AA https://www.youtube.com/watch?v=j973645y5AA
implements 6y ago
That’s my understanding - “confined” meaning nothing flying tangentially away from the engine and hitting the fuselage or wing. Saying that, resultant vibration causing the inlet and nacelle cowling to separate isn’t supposed to happen either - because of the serious risk to the tail.

I thought it was 'confined' if the containment ring did its job? If it had failed (like not supposed to) it would have been a whole lot worse.

by hazeii 6y ago

I thought it was 'confined' if the containment ring did its job? If it had failed (like not supposed to) it would have been a whole lot worse.

colechristensen 6y ago

The plane landed and didn’t blast enormous holes with ejected compressor blades. That’s a successful failure.

underseacables 6y ago
Is that what happenes when The fan blades fly off and hit the airplane?
- kyshoc 6y ago
  That’s almost exactly what happened on Southwest 1380[0] a few years ago. [0]: https://en.wikipedia.org/wiki/Southwest_Airlines_Flight_1380 https://en.wikipedia.org/wiki/Southwest_Airlines_Flight_1380
- hazeii 6y ago
  As ever, more detail and clear explanations on pprune[0]. As one commenter put it, to an ER doctor this is a shallow wound with lots of blood. [0] https://www.pprune.org/rumours-news/638797-united-b777-uncontained-engine-failure.html https://www.pprune.org/rumours-news/638797-united-b777-uncon...
- colechristensen 6y ago
  Pieces on the inside of jet engines are spinning between 2,000 and 12,000 rpm. They should all be properly contained in an airliner, but before that was the case of one fan blade broke and hit the plane it could look like a bomb blew an enormous hole in the side of the plane. These small pieces have a huge kinetic energy because they’re spinning so fast. Nothing bad happening, everyone uninjured and a plane making an orderly airport emergency landing is many layers of safety systems all working properly.
  - dredmorbius 6y ago
    Hull penetration at altitude can lead to explosive decompression, and, depending on the specifics of the penetration, complete hull loss. Airplanes are big fragile inflated sausages, and it takes relatively little by way of explosive to down one. An early model (the de Havilland Comet, operated by BOAC and South African Airways in the 1950s) was downed due to a design flaw leading to metal fatigue around the windows, with three aircraft lost in 12 months due to in-flight break-ups, 99 souls lost. Even at lower altitudes, an uncontained fan or turbine failure can be rough on the cargo or passengers, either from direct shrapnel, decompression, or (partial or full) egress. https://www.bbc.com/news/world-us-canada-43803340 https://www.bbc.com/news/world-us-canada-43803340
- touisteur 6y ago
  Ugh look up QF-72 for an A380 Rolls-Royce engine containment failure...
  - mcdevilkiller 6y ago
    Are you sure? That was an A330, and a failure on one ADIRU.
    - touisteur 6y ago
      Aaaaaah always mixing this and QF-32 :-( sorry. The book by Richard de Crespigny is a must read if you can find it. Great.
  - martyvis 6y ago
    QF-32. (BTW the pilot Richard Champion de Crespigny wrote a fantastic book on the incident. The intensity of going though procedures on an iPad and manuals as alarms were going off, while remembering to just fly the plane, was the thing that most sticks in my mind.
    - touisteur 6y ago
      Sorry, right, always mixing up those two. Best lessons from the book for me are: 1- meet the designers, understand the "why"s and not only the descriptive posthoc documentation 2- when you don't trust your instruments, keep following the procedures, checklists, (for this you need an excellent, trained, cold-headed team), and eventually try to reconstruct 'what aircraft you have' 3- trust the automated checklists but not too much! Crosscheck what's asked of you, with what you know of the aircraft. Since you know the 'why's you know the automated checklist system's designers probably never expected an aircraft with that much damage to keep flying... 4- there are no hall-passes for heroes. At the end De Crespigny fails his evaluation (the flight was an evaluation flight, with an instructor on board). All around a great, great book for systems people.
- lm28469 6y ago
  Most of the "skin" of a plane is only a few mm thick [0] it doesn't take much to puncture, I mean, it does, but thin turbine blades made to resist birds impact at 10k rpm would cut through it like butter. [0] https://aviation.stackexchange.com/questions/45566/how-thick-is-the-skin-of-an-aircraft-like-the-airbus-a350-or-boeing-b777 https://aviation.stackexchange.com/questions/45566/how-thick...
- benhurmarcel 6y ago
  To add to the topic, aircraft structure and systems are made to withstand the projection of those debris hitting with "infitite" energy. That means for every trajectory possible, it's considered that a part flies through everything in its path. The aircraft still has to land.
  - o-__-o 6y ago
    The wing is an exceptionally strong component of the aircraft. It’s usually the freak accidents where you hear of a fuel tank being ruptured or control or hydraulic lines being cut. In all of these accidents I bet there is wing damage but the plane is able to continue as usual WW2 fighter planes anyone?
hazeii 6y ago
Plenty of youtube videos of a blade-off test - here's a short one [0] of an A380 Rolls Royce engine testing. That's about £9,000,000 of engine being destroyed in this (successful) test. [0] https://www.youtube.com/watch?v=5-8_Gnbp2JA https://www.youtube.com/watch?v=5-8_Gnbp2JA
- dtgriscom 6y ago
  At the beginning of the video the blades seem to be spinning at about 2RPS, but after the explosion they're spinning much faster. I presume the former was an artifact of the camera's frame rate.
  - hazeii 6y ago
    They normally have high-speed cameras running; that short video is a mish-mash of super-slow-mo and regular speed footage. There are much longer versions on YT, e.g. this one [0] which covers it in more detail (watch the people in the room jump when it blows - despite being a fair distance away). [0] https://www.youtube.com/watch?v=j973645y5AA https://www.youtube.com/watch?v=j973645y5AA

implements 6y ago

That’s my understanding - “confined” meaning nothing flying tangentially away from the engine and hitting the fuselage or wing. Saying that, resultant vibration causing the inlet and nacelle cowling to separate isn’t supposed to happen either - because of the serious risk to the tail.