A380 engine piece found in Groenland after 9 months
Join Date: Oct 2003
Location: UK
Posts: 5
Likes: 0
Received 0 Likes
on
0 Posts
I would assume that since this was pretty clearly an engine failure, GE would be picking up the tab - if not all, at least the lions share. That's pretty standard procedure - when the cargo door blew out of the United 747 near Hawaii, Boeing spent a boatload of cash to find and recover the door so they could find out what went wrong and make sure it didn't happen again.
For design purposes, we assumed the probability of an uncontained engine failure (typically a rotor burst) at 10-8/hr, the current regulatory guidance requires a "one in twenty" analysis for rotor bursts - meaning the analysis needs to show that the probability of a rotor burst resulting in a catastrophic accident should be 5% or less.
However the engine company designs the rotors - especially the fan disc - to never fail. So, just like Sioux City, it's critically important to find out why it did fail so they can take appropriate action to prevent a future event.
BTW, IIRC, they traced the Sioux City fan disc failure to a flaw in the source material used to make the disc. There were nine other fan discs made from that same batch of material, which were promptly removed from service.
For design purposes, we assumed the probability of an uncontained engine failure (typically a rotor burst) at 10-8/hr, the current regulatory guidance requires a "one in twenty" analysis for rotor bursts - meaning the analysis needs to show that the probability of a rotor burst resulting in a catastrophic accident should be 5% or less.
However the engine company designs the rotors - especially the fan disc - to never fail. So, just like Sioux City, it's critically important to find out why it did fail so they can take appropriate action to prevent a future event.
BTW, IIRC, they traced the Sioux City fan disc failure to a flaw in the source material used to make the disc. There were nine other fan discs made from that same batch of material, which were promptly removed from service.
Join Date: Feb 2019
Location: shiny side up
Posts: 431
Likes: 0
Received 0 Likes
on
0 Posts
That's pretty standard procedure - when the cargo door blew out of the United 747 near Hawaii, Boeing spent a boatload of cash to find and recover the door so they could find out what went wrong and make sure it didn't happen again.
First off, that was not the first time a 747 door had failed, ....the incident you cite where the door had failed in 1989 on a Pan Am flight near HI, it was at least the second reported incident. There was a failure reported 2 years earlier...
WHY Boeing spent so much time on finding the door, was they did not correct the door failure after the first failure.
The next time the door failed, 2 years later, on a United Airlines 747 near Honolulu in 1989, the Boeing jet faced an “explosive decompression,” and nine passengers were “ejected from the airplane and lost at sea.
This is why they spent so much time and money, was that their lack of response in correcting the design fault, that has now killed 9 people....trying to determine blame...well...yes, they certainly had an impetus to make sure it did not happen again, they just killed 9 people on a known issue.
From the final report:
Also contributing to the accident was a lack of timely corrective actions by Boeing and the FAA following a 1987 cargo door-opening incident on a Pan Am B-747,” the NTSB said.
How many people did their lack of response to a known issue, put at risk, and kill with the MAX?
Face it, Boeing knew the issues, and failed to disclose to the FAA and the pilots...putting at risk EVERYONE who flew on those aircraft since being certified to fly.
Last edited by Smythe; 3rd Jul 2019 at 01:49.
The industry, including operators does not have the capacity to ground aircraft after every incident while they come up with fixes that actually work and not cause other problems. Sure every manufacturer considers a cargo door failure and the resulting decompression. But just how big a decompression rate is judged based on the opening per unit time and the ability to bleed off pressure waves that can take out other systems. The United event was a wake up or surprise that the decompression wake would eject passenger seats in whole. Thus the magnitude of the system involvement from the passenger standpoint surprised us all. Hence the reaction after the event.
But let's get back to this thread subject. The surprise to me was how little secondary damage to systems actually occurred with such a massive fan disk failure. But that surprise while welcomed.doesn't make us sleep well in light of other historical events like Sioux city etc.. So once again we go to the extra work of getting more information by finding key parts.to better understand what corrective actions are warranted throughout the operators
Join Date: Jun 2009
Location: in the barrel
Posts: 147
Likes: 0
Received 0 Likes
on
0 Posts
Join Date: Sep 2011
Location: Northern Territory Australia
Posts: 105
Likes: 0
Received 0 Likes
on
0 Posts
Conspiracy Theory
Yes, it melts every year in the "summer" and freezes again in the winter. Strange that.
But this isn't a GW forum -
https://www.telegraph.co.uk/comment/...-thin-ice.html
But this isn't a GW forum -
https://www.telegraph.co.uk/comment/...-thin-ice.html
Join Date: Jul 2013
Location: In a Pineapple Under the Sea
Age: 61
Posts: 152
Likes: 0
Received 0 Likes
on
0 Posts
Join Date: Jan 2008
Location: another place
Posts: 736
Likes: 0
Received 0 Likes
on
0 Posts
WHY Boeing spent so much time on finding the door, was they did not correct the door failure after the first failure.
Seems a Boeing thing to wait for two accidents....
Seems a Boeing thing to wait for two accidents....
Join Date: Jan 2019
Location: Up
Posts: 103
Likes: 0
Received 0 Likes
on
0 Posts
Join Date: Aug 2003
Location: FR
Posts: 234
Likes: 0
Received 0 Likes
on
0 Posts
esp @tdracer (off topic) re. rotor burst. A while ago we saw photos of a large blade fragment stuck in the "containment belt" (proper term = ?) Would you think this could have been the "root cause" (how come it was not dislodged by the rest?) When you say fan disc designed not to fail, does that include when N-1 blades keep hitting a rigid obstacle until the fan stops turning?
esp @tdracer (off topic) re. rotor burst. A while ago we saw photos of a large blade fragment stuck in the "containment belt" (proper term = ?) Would you think this could have been the "root cause" (how come it was not dislodged by the rest?) When you say fan disc designed not to fail, does that include when N-1 blades keep hitting a rigid obstacle until the fan stops turning?
Walk out under extreme vibratory loads with disk intact (ala NA CF6 in Albuquerque
Slip out when crack that breaks the disk opens up between OD and ID
The Kevlar belt will give a couple of feet outwards as the rotor pushes outward leaving lots of room for lesser debris to escape being driven through the Kevlar. The rest of the metal case the Kevlar is wrapped around just gives up right away
To add a bit to what lomapaseo wrote:
Blade out events are extremely dynamic - every one is different and the results are not really repeatable. They run the full blown engine test once (generally after several smaller 'rig tests' to make sure things will work as designed) and hope that it passes - pass/fail being nothing goes out tangentially through the containment system, nothing important 'falls off', and the engine quits 'gracefully'. The blade is released by a small explosive charge in the root with the engine running at redline N1. The blade will hit the next (trailing) blade and containment ring (even the older steel ones would distort very dramatically), then the pieces tend to come back in and cause havoc, damaging the rest of the fan blades (occasionally even breaking off another blade), while the sudden imbalance causes massive vibrations of the whole mess. If you get a chance to watch one of the slow motion videos, do it - the amount of destruction and way everything moves around and distorts is simply amazing. By design, the fan disc shouldn't fail, although it'll likely lose bits of the fan blade attachment dovetails. Way back ~30 years ago when they did the fan blade out for the original PW4000, part of a fan blade made it through the (steel) containment ring and was embedded in the (fan case mounted) FADEC - interestingly that was considered a 'pass' since it didn't escape the engine...
Cause of a fan blade out are varied - oftentimes it's not an entire blade - the blade fails someplace outboard of the root (metal fatigue - possibly caused by FOD induced blade damage), I recall a Trent 800 event which was caused by wear of the blade dovetail due to inadequate lubrication of the dovetail. They do the test releasing an entire blade since that's considered to be worst case.
On the original GE90, when they did the blade out test the containment system worked, and the engine shutdown gracefully, but all sorts of stuff fell off - the inlet, parts of the gearbox, etc. GE argued that they could show by analysis that they'd solved the problem of stuff falling off, but the FAA didn't buy it and made them re-run the test, destroying another expensive engine in the process.
Blade out events are extremely dynamic - every one is different and the results are not really repeatable. They run the full blown engine test once (generally after several smaller 'rig tests' to make sure things will work as designed) and hope that it passes - pass/fail being nothing goes out tangentially through the containment system, nothing important 'falls off', and the engine quits 'gracefully'. The blade is released by a small explosive charge in the root with the engine running at redline N1. The blade will hit the next (trailing) blade and containment ring (even the older steel ones would distort very dramatically), then the pieces tend to come back in and cause havoc, damaging the rest of the fan blades (occasionally even breaking off another blade), while the sudden imbalance causes massive vibrations of the whole mess. If you get a chance to watch one of the slow motion videos, do it - the amount of destruction and way everything moves around and distorts is simply amazing. By design, the fan disc shouldn't fail, although it'll likely lose bits of the fan blade attachment dovetails. Way back ~30 years ago when they did the fan blade out for the original PW4000, part of a fan blade made it through the (steel) containment ring and was embedded in the (fan case mounted) FADEC - interestingly that was considered a 'pass' since it didn't escape the engine...
Cause of a fan blade out are varied - oftentimes it's not an entire blade - the blade fails someplace outboard of the root (metal fatigue - possibly caused by FOD induced blade damage), I recall a Trent 800 event which was caused by wear of the blade dovetail due to inadequate lubrication of the dovetail. They do the test releasing an entire blade since that's considered to be worst case.
On the original GE90, when they did the blade out test the containment system worked, and the engine shutdown gracefully, but all sorts of stuff fell off - the inlet, parts of the gearbox, etc. GE argued that they could show by analysis that they'd solved the problem of stuff falling off, but the FAA didn't buy it and made them re-run the test, destroying another expensive engine in the process.
Join Date: Jan 2008
Location: Ban Chiang,Thailand
Age: 67
Posts: 191
Likes: 0
Received 0 Likes
on
0 Posts
Oh hell yea they did...
First off, that was not the first time a 747 door had failed, ....the incident you cite where the door had failed in 1989 on a Pan Am flight near HI, it was at least the second reported incident. There was a failure reported 2 years earlier...
WHY Boeing spent so much time on finding the door, was they did not correct the door failure after the first failure.
The next time the door failed, 2 years later, on a United Airlines 747 near Honolulu in 1989, the Boeing jet faced an “explosive decompression,” and nine passengers were “ejected from the airplane and lost at sea.
This is why they spent so much time and money, was that their lack of response in correcting the design fault, that has now killed 9 people....trying to determine blame...well...yes, they certainly had an impetus to make sure it did not happen again, they just killed 9 people on a known issue.
From the final report:
Also contributing to the accident was a lack of timely corrective actions by Boeing and the FAA following a 1987 cargo door-opening incident on a Pan Am B-747,” the NTSB said.
How many people did their lack of response to a known issue, put at risk, and kill with the MAX?
Face it, Boeing knew the issues, and failed to disclose to the FAA and the pilots...putting at risk EVERYONE who flew on those aircraft since being certified to fly.
First off, that was not the first time a 747 door had failed, ....the incident you cite where the door had failed in 1989 on a Pan Am flight near HI, it was at least the second reported incident. There was a failure reported 2 years earlier...
WHY Boeing spent so much time on finding the door, was they did not correct the door failure after the first failure.
The next time the door failed, 2 years later, on a United Airlines 747 near Honolulu in 1989, the Boeing jet faced an “explosive decompression,” and nine passengers were “ejected from the airplane and lost at sea.
This is why they spent so much time and money, was that their lack of response in correcting the design fault, that has now killed 9 people....trying to determine blame...well...yes, they certainly had an impetus to make sure it did not happen again, they just killed 9 people on a known issue.
From the final report:
Also contributing to the accident was a lack of timely corrective actions by Boeing and the FAA following a 1987 cargo door-opening incident on a Pan Am B-747,” the NTSB said.
How many people did their lack of response to a known issue, put at risk, and kill with the MAX?
Face it, Boeing knew the issues, and failed to disclose to the FAA and the pilots...putting at risk EVERYONE who flew on those aircraft since being certified to fly.
Here in the UK lawyers are grubbing like mad for business over PPI mis-selling, so maybe our lern'd friends are missing a trick?.
Join Date: Jan 2008
Location: Ban Chiang,Thailand
Age: 67
Posts: 191
Likes: 0
Received 0 Likes
on
0 Posts
Join Date: Aug 2003
Location: FR
Posts: 234
Likes: 0
Received 0 Likes
on
0 Posts
re. fan hub design & test ... and successful blade out tests are then fully analyzed .(the hub) ... to gain confidence in the "design to never fail" in the sense would not risk separating as a big piece as in AF66 ?