5 ms·

There might be some truth in that. But the report doesn't confirm that theory.

by cj 11mo ago

philip1209 11mo ago
I'm presenting it "useful not true" - not an RCA.
rconti 11mo ago
What theory? That the mount failed? Or the rotation of the engine in the photos going up and over the fuselage? It seems like both are true, but doesn't necessarily prove WHY the mount failed.
- cj 11mo ago
  That the engine was flung into the fuselage due to gyroscopic forces.
  - inejge 11mo ago
    Well, some force flung it inboard and above the fuselage (gods, that CCTV stills sequence.) Knowing that the engine rotates CCW, there are not many candidates.
    - JumpCrisscross 11mo ago
      > Knowing that the engine rotates CCW, there are not many candidates There are lots of candidates for a failing engine yeeting itself in any direction.
      - inejge 11mo ago
        > There are lots of candidates for a failing engine yeeting itself in any direction. For the precise trajectory, certainly; for the general direction, not so much. Could you describe a combination of forces that would have thrown that engine to the left of the direction of travel? (We're talking about this accident, not any engine anywhere.)
        JumpCrisscross 11mo ago
        > Could you describe a combination of forces that would have thrown that engine to the left of the direction of travel? Foreign object gets yeeted to the right. Internal component gets yeeted to the right. Engine exploded on its right side. I think each of those is more likely than gyroscopics since the engine went to the left. Not left and up.
        inejge 11mo ago
        > [...] the engine went to the left. Not left and up. Whatever you're describing, it's not this accident. Over and out.
        JumpCrisscross 11mo ago
        You're correct–I didn't look at the photos. My broad comment is that gyroscopic precession having any critical role in this is incredibly far fetched. That said, I've never flown or worked on a turbofan so ¯\_(ツ)_/¯.
  - sandworm101 11mo ago
    Gyroscopic forces might have changed the direction of travel a few degrees, but the motive force comes from the engine's thrust, the power of its spinning blades pushing air. An engine cut loose at full power moves forward like a missile.
- scottlamb 11mo ago
  Not an aviation expert at all, so take this with a grain of salt, but I think "the spinning engine resists changes to the direction of its spin axis" offers two important insights: * why it failed at rotation (the first/only sudden change of direction under full throttle) rather than as soon as it was mounted onto the plane, while taxiing, as soon as they throttled up, mid-flight, or on landing. This is important because at rotation is the worst possible time for this failure: no ability to abort take-off, no ability to land safety under no or severely limited power, little time to react at all, full fuel. Knowing these failures are likely to manifest then stresses the importance of avoiding them. * why it failed in such a way that it damaged the rest of the plane. Not so much what was wrong with the mounting in the first place, if that's what you're asking. Presumably it was designed to withstand the forces of this moment and clearly has done so many times before.
  - psunavy03 11mo ago
    > Presumably it was designed to withstand the forces of this moment and clearly has done so many times before. The report seems to suggest metal fatigue in the motor mount may be a possible culprit.
    - magicalhippo 11mo ago
      Not the motor mount but the pylon mount. The pylon was found attatched to the engine with both engine mounts attached. But yes, the report mentions stress factures where the aft pylon mount failed.
- deleted 11mo ago
  [deleted]
stackghost 11mo ago
This is a preliminary report. Its purpose is to present initial evidence/information. The final reports are always much more comprehensive.

There might be some truth in that. But the report doesn't confirm that theory.

by cj 11mo ago

There might be some truth in that. But the report doesn't confirm that theory.

philip1209 11mo ago

I'm presenting it "useful not true" - not an RCA.

rconti 11mo ago

What theory? That the mount failed? Or the rotation of the engine in the photos going up and over the fuselage? It seems like both are true, but doesn't necessarily prove WHY the mount failed.

cj 11mo ago
That the engine was flung into the fuselage due to gyroscopic forces.
- inejge 11mo ago
  Well, some force flung it inboard and above the fuselage (gods, that CCTV stills sequence.) Knowing that the engine rotates CCW, there are not many candidates.
  - JumpCrisscross 11mo ago
    > Knowing that the engine rotates CCW, there are not many candidates There are lots of candidates for a failing engine yeeting itself in any direction.
    - inejge 11mo ago
      > There are lots of candidates for a failing engine yeeting itself in any direction. For the precise trajectory, certainly; for the general direction, not so much. Could you describe a combination of forces that would have thrown that engine to the left of the direction of travel? (We're talking about this accident, not any engine anywhere.)
      - JumpCrisscross 11mo ago
        > Could you describe a combination of forces that would have thrown that engine to the left of the direction of travel? Foreign object gets yeeted to the right. Internal component gets yeeted to the right. Engine exploded on its right side. I think each of those is more likely than gyroscopics since the engine went to the left. Not left and up.
        inejge 11mo ago
        > [...] the engine went to the left. Not left and up. Whatever you're describing, it's not this accident. Over and out.
        JumpCrisscross 11mo ago
        You're correct–I didn't look at the photos. My broad comment is that gyroscopic precession having any critical role in this is incredibly far fetched. That said, I've never flown or worked on a turbofan so ¯\_(ツ)_/¯.
- sandworm101 11mo ago
  Gyroscopic forces might have changed the direction of travel a few degrees, but the motive force comes from the engine's thrust, the power of its spinning blades pushing air. An engine cut loose at full power moves forward like a missile.
scottlamb 11mo ago
Not an aviation expert at all, so take this with a grain of salt, but I think "the spinning engine resists changes to the direction of its spin axis" offers two important insights: * why it failed at rotation (the first/only sudden change of direction under full throttle) rather than as soon as it was mounted onto the plane, while taxiing, as soon as they throttled up, mid-flight, or on landing. This is important because at rotation is the worst possible time for this failure: no ability to abort take-off, no ability to land safety under no or severely limited power, little time to react at all, full fuel. Knowing these failures are likely to manifest then stresses the importance of avoiding them. * why it failed in such a way that it damaged the rest of the plane. Not so much what was wrong with the mounting in the first place, if that's what you're asking. Presumably it was designed to withstand the forces of this moment and clearly has done so many times before.
- psunavy03 11mo ago
  > Presumably it was designed to withstand the forces of this moment and clearly has done so many times before. The report seems to suggest metal fatigue in the motor mount may be a possible culprit.
  - magicalhippo 11mo ago
    Not the motor mount but the pylon mount. The pylon was found attatched to the engine with both engine mounts attached. But yes, the report mentions stress factures where the aft pylon mount failed.
deleted 11mo ago
[deleted]

stackghost 11mo ago

This is a preliminary report. Its purpose is to present initial evidence/information. The final reports are always much more comprehensive.