111–120 of 188 posts
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Why would you be afraid for them when the Orion capsule worked so flawlessly...oh right.
Are you talking about Starliner? Starliner's 2 flights have been problematic to say the least, but Orion's single (uncrewed) flight went pretty well.
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> Once that bearing is gone the stress that it would normally allow to escape on account of rotation would be directly transferred to the metal around it The bearing would have to sieze up and the bearing axle be locked to the race. There is some limit to rotational torque even with a siezed bearings. Metaphor: arthritic joints are not smooth, but they will rotate if given enough torque. From the images, it looks lik…
The forces on that mount are pretty extreme. Once the bearing seized it was really a matter of time before something gave and given the strength of the casing as well as the strength of the material and mount points it was a toss-up between the bolts and the casing. The previous evidence showed a clear order to the bolts breaking suggesting one bolt was heavier loaded than the remaining ones. The new evidence points…
Yeah. Worn or seized bearings are relevant to rotation, but on second thoughts, rotation isn't the issue here.
Rereading the PDF, I can see that I entirely misunderstood the function of the bearing and how it failed, and I suspect I've mislead you. The two lugs mislead me! I would guess they make the lug as two parts for redundancy (if the lug was a single part then it's failure would be bad). My previous comment was wildly incorrect about rotation, but now I think rotation is not the issue.
The casing split in half all the way around the circumference at the weakest point (where the recess is), splitting into two pieces, a forward half and a rearward half. The half forward of the split moves forward and the half rearward of the split moves rearward. That is what they inspect for every sixty months to see if the bearing casing has broken.
An unbroken casing is normally prevented from moving forward or backwards by the ball (how the hell do they make the bearing like that?!).
It appears that the unbroken casing itself is designed for the outside to be able to slide forwards and backwards within the lugs (very little movement?).
The primary force this bearing is preventing is pitching of the engine relative to the wing (vertical force). And secondarily to prevent yawing of the engine relative to the wing (horizontal force). Rotation (roll of the engine relative to the wing) has to be prevented by the main mount and the engine surely can't twist much therefore I suspect rotational forces at that bearing are rather irrelevant.
As the engine thrusts and stops thrusting, the thrust changes create pitching forces on the engine, and there would be vertical movement at the broken bearing - a clunk!?
The main mount would flex a little more due to the extra pitch movement; and I guess we'll have to wait and see whether the bearing failure is relevant to the crash. It appears to be a smoking gun, but could be a red herring?
The main mount is obviously not supposed to fail even if that bearing has broken.
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33 percent attrition and could only fly once a week. I know satellites and drones have replaced the sr71 but it would be cool if someone would build a plane as capable again.
It was replaced because the USSR managed to shoot one down. Spy satellites are as of yet off limits.
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> they paid extra for the redundant AOA sensor. There was no redundancy AOA sensor option for MCAS. All the planes were built with two AOA sensors, with the original MCAS implementation only using data from 1 sensor.
Correct. And you could pay for the MCAS to use both sensors which all US airlines did. Edit: I was misremembering. Both sensors were enabled on all planes and MCAS only used one at a time on all planes. What was disabled, unless paid for, was software which displayed to the pilots that the 2 sensors were disagreeing, which would immediately have alerted them to what may have been wrong. > According to Bjorn Fehrm, Ae…
Is that what I'm reading?
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Correct. And you could pay for the MCAS to use both sensors which all US airlines did. Edit: I was misremembering. Both sensors were enabled on all planes and MCAS only used one at a time on all planes. What was disabled, unless paid for, was software which displayed to the pilots that the 2 sensors were disagreeing, which would immediately have alerted them to what may have been wrong. > According to Bjorn Fehrm, Ae…
It’s kinda darkly refreshing that purchases in the tens/hundreds of millions of dollars still try to nickel and dime you.
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The forces on that mount are pretty extreme. Once the bearing seized it was really a matter of time before something gave and given the strength of the casing as well as the strength of the material and mount points it was a toss-up between the bolts and the casing. The previous evidence showed a clear order to the bolts breaking suggesting one bolt was heavier loaded than the remaining ones. The new evidence points…
> What you describe is a worn bearing with an excess of play, not a seized one Yeah. Worn or seized bearings are relevant to rotation, but on second thoughts, rotation isn't the issue here. Rereading the PDF, I can see that I entirely misunderstood the function of the bearing and how it failed, and I suspect I've mislead you. The two lugs mislead me! I would guess they make the lug as two parts for redundancy (if the…
Earlier quoted context omitted.
Correct. And you could pay for the MCAS to use both sensors which all US airlines did. Edit: I was misremembering. Both sensors were enabled on all planes and MCAS only used one at a time on all planes. What was disabled, unless paid for, was software which displayed to the pilots that the 2 sensors were disagreeing, which would immediately have alerted them to what may have been wrong. > According to Bjorn Fehrm, Ae…
Wait so this is like the bmw heated seat thing? Where all cars have the heaters but they are only enabled via software if you pay? But in an airplane? Is that what I'm reading?
Earlier quoted context omitted.
Correct. And you could pay for the MCAS to use both sensors which all US airlines did. Edit: I was misremembering. Both sensors were enabled on all planes and MCAS only used one at a time on all planes. What was disabled, unless paid for, was software which displayed to the pilots that the 2 sensors were disagreeing, which would immediately have alerted them to what may have been wrong. > According to Bjorn Fehrm, Ae…
Wait so this is like the bmw heated seat thing? Where all cars have the heaters but they are only enabled via software if you pay? But in an airplane? Is that what I'm reading?
If you want to see the way this looks on the flight displays that a pilot sees, this video shows some examples (generated from a flight simulator): https://youtu.be/L5KQ0g_-qJs?si=AtYkellEROnHZ89e&t=349
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Stand outside an engine test cell for a while and tell me that maintenance crews don't deal with emergencies. I'll bet they do so more often than pilots, we just don't hear about it because there are no passengers at risk. Nobody is going to make a 'Sully' like movie about the maintenance mechanic that spotted an issue with a part under test before it led to one or more catastrophic failures. They're more likely to m…
I didn't say there aren't any emergencies, but the emergencies are not on the same level. And I said they're highly trained, you don't need to convince me of that. Nor do you need to convince me they're important. Those are entirely separate issues. Also what fraction of engine test cell use is for engine maintenance? Is it a big amount? But if that kind of test goes wrong the main outcomes are "hit stop" and "oh no…
After every overhaul. Typically every 2500 to 15000 hours depending on the type of engine and the workload. It depends on many economic factors whether or not an overhaul is economical, in some cases it is cheaper just to buy a new engine.