AA 763 engine failure on ground run
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So that no one misunderstands the gravity of this, it is not unusual for an uncontained failure of one low-mounted engine to cause secondary shrapnel damage to an opposite engine. The escaping projectiles are traveling so fast that slipstream has virtually no effect.
The object protruding from the outboard side of #2 engine in the LAFD photo appears to me to be a section of a HP turbine disc (a few hundred Kg) which left the #1 engine a very few milliseconds earlier, traveled horizontally under the fuselage, tore a gash in the belly, and almost tore completely thruogh #2. An instant double engine failure.
Fortunately, uncontained failures are VERY rare due to some of the highest design and maintenance standards in any industry.
The object protruding from the outboard side of #2 engine in the LAFD photo appears to me to be a section of a HP turbine disc (a few hundred Kg) which left the #1 engine a very few milliseconds earlier, traveled horizontally under the fuselage, tore a gash in the belly, and almost tore completely thruogh #2. An instant double engine failure.
Fortunately, uncontained failures are VERY rare due to some of the highest design and maintenance standards in any industry.
Too mean to buy a long personal title
Originally Posted by Hiflyer1757
Sept 22 2000 USAir had a similar incident...same motors...same type high speed runup by mtc...except that the hpt stage 1 disk went up and over the aircraft into the river. AC was written off due to fire damage. N654US.
[Sorry that information is the exactly wrong way around, as correctly pointed out by barit1 below.
]The experts will know what the differences are, and if they make any difference!
Last edited by Globaliser; 7th Jun 2006 at 21:42.
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Originally Posted by Globaliser
I'm not normally so anoraky, but as I'd looked this up for someone else: Technically the US Airways aircraft had CF6-80A2s, and this incident aircraft has CF6-80C2B2s...
And that last batch of pix from OVERTALK leads me to correct my earlier statement of a double engine failure; the chunk of HPT disc from #1 JUST MISSED #2's turbomachinery, although I have no idea how.
In all likelihood #2 could have continued running.
Too mean to buy a long personal title
Sorry, you are absolutely right. I looked back at what I'd written before (elsewhere) and realised that I'd managed to read it A over T. Thanks!
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Scary to see a full turbine disk having left the engine. During certification normally one third of a disk is seen as the worst case scenario, and even for such event a small risk of a catastrophic result is accepted.
I wonder whether the NTSB will analyse this event, as it was not during operation. I would be really interested in the chain of events of the breakup, it it is possible to determine it. Nomally you assume that the fracture of a turbine disk causes the failure, but the disk is in one piece this time.
I wonder whether the NTSB will analyse this event, as it was not during operation. I would be really interested in the chain of events of the breakup, it it is possible to determine it. Nomally you assume that the fracture of a turbine disk causes the failure, but the disk is in one piece this time.
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Originally Posted by Volume
Scary to see a full turbine disk having left the engine. During certification normally one third of a disk is seen as the worst case scenario, and even for such event a small risk of a catastrophic result is accepted.
I wonder whether the NTSB will analyse this event, as it was not during operation. I would be really interested in the chain of events of the breakup, it it is possible to determine it. Nomally you assume that the fracture of a turbine disk causes the failure, but the disk is in one piece this time.
I wonder whether the NTSB will analyse this event, as it was not during operation. I would be really interested in the chain of events of the breakup, it it is possible to determine it. Nomally you assume that the fracture of a turbine disk causes the failure, but the disk is in one piece this time.
http://www.iasa-intl.com/folders/bel...gineFire-3.htm
There was an AD on the subject of cracking on the dovetail slots of HPT disks on the CF6-80, along with service bulletins from GE. Interesting as related reading:
http://www.airweb.faa.gov/Regulatory...pandSection=-4
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James
Great pictures, certainly not what a CF6-80 should do on an EGR...
I can't believe that section of failed turbine disk wedged where it did!
BAe146?? AND Metallurgically flawed turbine disks??
Great pictures, certainly not what a CF6-80 should do on an EGR...
I can't believe that section of failed turbine disk wedged where it did!
BAe146?? AND Metallurgically flawed turbine disks??
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Come to think of it if those pictures haven't been reversed or messed about , it's O/B of #2 engine that has the wedged Turbine disk section!
#1 was the suspect engine right??? Just think, the Speed & Inertia
of what took place! Lucky no AMTs were injured or worse...
BAe146??
#1 was the suspect engine right???
Just think, the Speed & Inertia of what took place! Lucky no AMTs were injured or worse...
BAe146??
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Per the www.aero-news.net link above:
" ...the high-pressure turbine stage one disk on the number one engine, a GE CF6-80A2, broke into several pieces that were later found embedded in the fuselage, the number two engine, and scattered as far as 3,000 feet from the airplane. "
Once the stage one disc disintegrated, the stage two disc (still intact) had no means of support and rolled away at 10000 rpm. That is the intact disc seen at http://www.flickr.com/photos/lafd/se...7594153722446/ (LAFD photos)
" ...the high-pressure turbine stage one disk on the number one engine, a GE CF6-80A2, broke into several pieces that were later found embedded in the fuselage, the number two engine, and scattered as far as 3,000 feet from the airplane. "
Once the stage one disc disintegrated, the stage two disc (still intact) had no means of support and rolled away at 10000 rpm. That is the intact disc seen at http://www.flickr.com/photos/lafd/se...7594153722446/ (LAFD photos)
Originally Posted by Volume
Scary to see a full turbine disk having left the engine. During certification normally one third of a disk is seen as the worst case scenario, and even for such event a small risk of a catastrophic result is accepted.
I wonder whether the NTSB will analyse this event, as it was not during operation. I would be really interested in the chain of events of the breakup, it it is possible to determine it. Nomally you assume that the fracture of a turbine disk causes the failure, but the disk is in one piece this time.
I wonder whether the NTSB will analyse this event, as it was not during operation. I would be really interested in the chain of events of the breakup, it it is possible to determine it. Nomally you assume that the fracture of a turbine disk causes the failure, but the disk is in one piece this time.
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Severity was understated in test of jet engine at LAX
Engine on American Airlines Boeing plane blew apart during a check nearly two weeks ago, causing a fire and sending metal half a mile away.
An explosion that ripped apart the engine of an American Airlines jet during a ground test at Los Angeles International Airport this month was far more dangerous than first reported, new details suggest.
The blast was strong enough to hurl an 18-inch chunk of metal more than half a mile -- across taxiways, service roads and two active runways. Airport workers found the piece two days later, not far from the airport's perimeter fence.
The investigation into what caused the engine to explode has focused in part on tiny cracks found on a key piece of the turbine. An Air New Zealand jetliner lost the same kind of engine to similar cracks in late 2002 and was forced to make an emergency landing.
"It was pretty fortunate that no one was hurt," LAX spokeswoman Nancy Castles said, "and that no planes were taking off or landing at that time."
The Boeing 767 jet had arrived in Los Angeles on a regular flight from New York City. Its flight crew had reported some kind of mechanical problem, so the airline sent the plane to maintenance after it landed at LAX.
An airline spokesman would not discuss that initial problem in any detail, saying only that it was unrelated to the engine failure that followed.
Workers were still trying to figure out what was wrong with the airplane when they pushed the throttle for both engines, and one of them blew apart.
The explosion outside the American Airlines maintenance hangar on June 2 sparked a small fire that sent a column of dark smoke over the passenger terminals at LAX and drew most of the initial attention. The explosion -- officially an "uncontained engine failure" -- gutted the engine and blackened part of the airplane's fuselage.
It also blasted pieces of the engine onto a nearby runway -- and, in one case, clear across the southern airfield. The workers who found that piece half a mile away described it as a wedge of metal, 2 inches thick, and heavy.
Other pieces punched through the airplane's fuselage and wings and embedded themselves in its other engine, according to a statement released Tuesday by the National Transportation Safety Board. Robert Ditchey, an aviation consultant in Marina del Rey who once oversaw maintenance for Pan American World Airways, called that especially worrisome.
Airline engine systems, he explained, have extra shielding that's supposed to protect the rest of the airplane from that kind of damage. Pieces of the engine, he said, "are not supposed to penetrate the fuselage" under any circumstance.
Three maintenance workers who were on the plane when the engine blew escaped without injury. Nobody on the ground was hurt, either -- despite the blast of metal pieces across taxiways and service roads usually swarming with airport workers.
Two federal agencies are looking into the explosion: the transportation safety board and the Federal Aviation Administration. Both have offices here but, in a sign of how important this investigation is, both sent special investigators from their Washington, D.C., headquarters.
Their investigations will determine whether the flaw that destroyed the engine was an isolated problem or could affect other airliners still in service. "I don't think there's any indication right now that this is a systemic problem," FAA spokeswoman Laura Brown said.
Investigators have found evidence of "fatigue cracking" on pieces of a disk from the engine's turbine, the safety board said in its brief statement.
Such cracks can develop from a microscopic flaw in the metal and weaken engine parts against the extraordinary stress they must endure.
The same kind of engine, built by General Electric, was the subject of an FAA order in 2003 that required regular inspections for fatigue cracks. The order was prompted by the emergency landing of the Air New Zealand plane after one of its engines spun apart and damaged a wing.
Such cracks are rare, Ditchey said, and should be caught by the rigorous inspections -- "down to the last nut and bolt" -- that airlines put their engines through. The materials used to build an aircraft engine, he added, are "the highest tech of the high-tech. It doesn't get any fancier than that."
Investigators have shipped pieces of the turbine disk shattered in the LAX explosion to the transportation safety board's laboratory in Washington, D.C., for further tests. The engine itself was sent to an American Airlines maintenance center in Oklahoma.
Airline spokesman Tim Wagner said he did not know how long the airplane had been in service. He said workers were conducting a routine maintenance check known as a run-up to diagnose an unrelated issue when the engine broke apart.
The airline, Wagner said, is "still in the process of refurbishing the aircraft."
from link
An explosion that ripped apart the engine of an American Airlines jet during a ground test at Los Angeles International Airport this month was far more dangerous than first reported, new details suggest.
The blast was strong enough to hurl an 18-inch chunk of metal more than half a mile -- across taxiways, service roads and two active runways. Airport workers found the piece two days later, not far from the airport's perimeter fence.
The investigation into what caused the engine to explode has focused in part on tiny cracks found on a key piece of the turbine. An Air New Zealand jetliner lost the same kind of engine to similar cracks in late 2002 and was forced to make an emergency landing.
"It was pretty fortunate that no one was hurt," LAX spokeswoman Nancy Castles said, "and that no planes were taking off or landing at that time."
The Boeing 767 jet had arrived in Los Angeles on a regular flight from New York City. Its flight crew had reported some kind of mechanical problem, so the airline sent the plane to maintenance after it landed at LAX.
An airline spokesman would not discuss that initial problem in any detail, saying only that it was unrelated to the engine failure that followed.
Workers were still trying to figure out what was wrong with the airplane when they pushed the throttle for both engines, and one of them blew apart.
The explosion outside the American Airlines maintenance hangar on June 2 sparked a small fire that sent a column of dark smoke over the passenger terminals at LAX and drew most of the initial attention. The explosion -- officially an "uncontained engine failure" -- gutted the engine and blackened part of the airplane's fuselage.
It also blasted pieces of the engine onto a nearby runway -- and, in one case, clear across the southern airfield. The workers who found that piece half a mile away described it as a wedge of metal, 2 inches thick, and heavy.
Other pieces punched through the airplane's fuselage and wings and embedded themselves in its other engine, according to a statement released Tuesday by the National Transportation Safety Board. Robert Ditchey, an aviation consultant in Marina del Rey who once oversaw maintenance for Pan American World Airways, called that especially worrisome.
Airline engine systems, he explained, have extra shielding that's supposed to protect the rest of the airplane from that kind of damage. Pieces of the engine, he said, "are not supposed to penetrate the fuselage" under any circumstance.
Three maintenance workers who were on the plane when the engine blew escaped without injury. Nobody on the ground was hurt, either -- despite the blast of metal pieces across taxiways and service roads usually swarming with airport workers.
Two federal agencies are looking into the explosion: the transportation safety board and the Federal Aviation Administration. Both have offices here but, in a sign of how important this investigation is, both sent special investigators from their Washington, D.C., headquarters.
Their investigations will determine whether the flaw that destroyed the engine was an isolated problem or could affect other airliners still in service. "I don't think there's any indication right now that this is a systemic problem," FAA spokeswoman Laura Brown said.
Investigators have found evidence of "fatigue cracking" on pieces of a disk from the engine's turbine, the safety board said in its brief statement.
Such cracks can develop from a microscopic flaw in the metal and weaken engine parts against the extraordinary stress they must endure.
The same kind of engine, built by General Electric, was the subject of an FAA order in 2003 that required regular inspections for fatigue cracks. The order was prompted by the emergency landing of the Air New Zealand plane after one of its engines spun apart and damaged a wing.
Such cracks are rare, Ditchey said, and should be caught by the rigorous inspections -- "down to the last nut and bolt" -- that airlines put their engines through. The materials used to build an aircraft engine, he added, are "the highest tech of the high-tech. It doesn't get any fancier than that."
Investigators have shipped pieces of the turbine disk shattered in the LAX explosion to the transportation safety board's laboratory in Washington, D.C., for further tests. The engine itself was sent to an American Airlines maintenance center in Oklahoma.
Airline spokesman Tim Wagner said he did not know how long the airplane had been in service. He said workers were conducting a routine maintenance check known as a run-up to diagnose an unrelated issue when the engine broke apart.
The airline, Wagner said, is "still in the process of refurbishing the aircraft."
from link
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Another photograph here, capturing the immediate aftermath:
http://www.airliners.net/open.file/1059747/L/
http://www.airliners.net/open.file/1059747/L/
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Originally Posted by JamesT73J
Another photograph here, capturing the immediate aftermath:
http://www.airliners.net/open.file/1059747/L/
http://www.airliners.net/open.file/1059747/L/
PP
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Originally Posted by GotTheTshirt
...I have the photos somewhere but on No 1 the compete gearbox sheered off held by the Hydraulic hoses and Generator cables !!
The No. 3 of course looked like a trick cigar
Also a piece of debris hit one of the aft RH windows and a passenger departed the aircraft - again missing the No 2 engine
The No. 3 of course looked like a trick cigar
Also a piece of debris hit one of the aft RH windows and a passenger departed the aircraft - again missing the No 2 engine
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The early built turbine disks were cut by cutting tools which then made about 10 or so turbine disks. Then the cutting tools were replaced and another 10 or so turbine disks were cut from stock.
Apparently the disks that have been failing are the ones that were made/cut last before changing the cutting tools. So now when turbine disks are made, the cutting tools are replaced sooner. This apparently made for a better quality turbine disk. This was on the early CF6-80 A series engines.
When the disk let go on Air NZ's 767 out of Brisbane, Australia, the engine stopped rotating, from climb power, in 42 revolutions. We counted this on the engine casing.
The force of this sudden stop made the aircraft yaw so hard that the co-pilot hit his head against the pillar between the windows. There were rumors that he was knocked out, but I'm not sure about that one.
Boeing was glad they strengthened up the plylon struts coz the engine would have fallen off the wing and I guess the airframe would have been lost. They knew this because a few years before Air nz's incident, a similar disk departure happened during a maintenance ground run where the entire engine fell off the wing and sat on the ground.
Have you guys ever wondered why there is a 'dry bay' area in the wing just above the turbine's? Its so an uncontained turbine failure, should it happen into the wing, can be survivable.
Post#17.
Apparently the disks that have been failing are the ones that were made/cut last before changing the cutting tools. So now when turbine disks are made, the cutting tools are replaced sooner. This apparently made for a better quality turbine disk. This was on the early CF6-80 A series engines.
When the disk let go on Air NZ's 767 out of Brisbane, Australia, the engine stopped rotating, from climb power, in 42 revolutions. We counted this on the engine casing.
The force of this sudden stop made the aircraft yaw so hard that the co-pilot hit his head against the pillar between the windows. There were rumors that he was knocked out, but I'm not sure about that one.
Boeing was glad they strengthened up the plylon struts coz the engine would have fallen off the wing and I guess the airframe would have been lost. They knew this because a few years before Air nz's incident, a similar disk departure happened during a maintenance ground run where the entire engine fell off the wing and sat on the ground.
Have you guys ever wondered why there is a 'dry bay' area in the wing just above the turbine's? Its so an uncontained turbine failure, should it happen into the wing, can be survivable.
Post#17.
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I recall a british air tours 737 that had an uncontained failure causing a fire , great damage and loss of life. type of engine was a pratt & whitney JT8d-?(15 or 17 or 9?).
I cannot recall what part of the engine broke apart, whether it was the compressor section or the turbine section.
Things can happen and really ruin your day. Engines on wings, next to fuel tanks scare me a bit in this scenario. Of course engines on the tail, near control cables can be messy too.
This article may be of interest:
Breakup of jet engine defies repair effort
By Matthew L. Wald The New York Times
Published: June 19, 2006
WASHINGTON U.S. investigators say they are deeply concerned about an engine breakup that nearly destroyed a Boeing 767 on the ground in Los Angeles on June 2 because the failure may be the third recurrence in six years of a problem they thought they had eliminated.
American Airlines mechanics were testing the engine after the crew of an earlier flight had reported that it was not performing properly. During the test, an internal disk came apart, slicing open a fuel tank in the left wing; the fuel spilled onto the ground, where it caught fire. One piece of metal was thrown 2,500 feet, or 760 meters, from the plane.
There were no injuries, and under the rules of the National Transportation Safety Board the event might not even qualify as an accident because there was no intention to fly the plane. But experts say that such "uncontained failures," so called because the engine cowling does not hold in the debris, resemble a roulette game.
"There's 360 degrees around, and it's really the luck of the draw which way the pieces come out," said John Goglia, a former member of the board and an aircraft maintenance expert. If the parts fly off in flight and hit the wing, where fuel is stored, or the fuselage, "the results could be pretty devastating."
The first such engine explosion occurred in July 1989, during a flight of a United Airlines DC-10. That engine was mounted in the tail, and the debris disabled the plane's hydraulic system. The crew brought the aircraft down in a field at the airport in Sioux City, Iowa, maneuvering only by varying the thrust on the two surviving engines; 111 people were killed.
The incident in Los Angeles is similar to one in September 2000 involving another Boeing 767, this one owned by US Airways, in Philadelphia. In both cases, mechanics were testing the engines by revving them toward full power when they broke up, leading to catastrophic fires.
In addition, an Air New Zealand 767 suffered an uncontained failure at 11,000 feet on a flight from Auckland to Brisbane, Australia, in December 2002. That plane landed safely. But as a result, in March 2003, the Federal Aviation Administration ordered inspections of the part involved. The agency believed that would solve the problem.
The Federal Aviation Administration is now investigating the failure in Los Angeles, said a spokeswoman, Laura Brown.
The engine in the incidents was a variant of the popular General Electric CF6.
Rick Kennedy, a spokesman for General Electric, said that about 3,400 of the engines were in service and that two- thirds of them had been inspected, with no problems found.
The engine involved in Los Angeles was not due for inspection, according to investigators.
The inspection interval is usually set at half the number of flights at which engineers think a problem will develop. The inspection limit now is 11,000 "cycles," or engine start-ups and shutdowns. Experts said that one likely outcome was that the government would require inspections at shorter intervals.
I cannot recall what part of the engine broke apart, whether it was the compressor section or the turbine section.
Things can happen and really ruin your day. Engines on wings, next to fuel tanks scare me a bit in this scenario. Of course engines on the tail, near control cables can be messy too.
This article may be of interest:
Breakup of jet engine defies repair effort
By Matthew L. Wald The New York Times
Published: June 19, 2006
WASHINGTON U.S. investigators say they are deeply concerned about an engine breakup that nearly destroyed a Boeing 767 on the ground in Los Angeles on June 2 because the failure may be the third recurrence in six years of a problem they thought they had eliminated.
American Airlines mechanics were testing the engine after the crew of an earlier flight had reported that it was not performing properly. During the test, an internal disk came apart, slicing open a fuel tank in the left wing; the fuel spilled onto the ground, where it caught fire. One piece of metal was thrown 2,500 feet, or 760 meters, from the plane.
There were no injuries, and under the rules of the National Transportation Safety Board the event might not even qualify as an accident because there was no intention to fly the plane. But experts say that such "uncontained failures," so called because the engine cowling does not hold in the debris, resemble a roulette game.
"There's 360 degrees around, and it's really the luck of the draw which way the pieces come out," said John Goglia, a former member of the board and an aircraft maintenance expert. If the parts fly off in flight and hit the wing, where fuel is stored, or the fuselage, "the results could be pretty devastating."
The first such engine explosion occurred in July 1989, during a flight of a United Airlines DC-10. That engine was mounted in the tail, and the debris disabled the plane's hydraulic system. The crew brought the aircraft down in a field at the airport in Sioux City, Iowa, maneuvering only by varying the thrust on the two surviving engines; 111 people were killed.
The incident in Los Angeles is similar to one in September 2000 involving another Boeing 767, this one owned by US Airways, in Philadelphia. In both cases, mechanics were testing the engines by revving them toward full power when they broke up, leading to catastrophic fires.
In addition, an Air New Zealand 767 suffered an uncontained failure at 11,000 feet on a flight from Auckland to Brisbane, Australia, in December 2002. That plane landed safely. But as a result, in March 2003, the Federal Aviation Administration ordered inspections of the part involved. The agency believed that would solve the problem.
The Federal Aviation Administration is now investigating the failure in Los Angeles, said a spokeswoman, Laura Brown.
The engine in the incidents was a variant of the popular General Electric CF6.
Rick Kennedy, a spokesman for General Electric, said that about 3,400 of the engines were in service and that two- thirds of them had been inspected, with no problems found.
The engine involved in Los Angeles was not due for inspection, according to investigators.
The inspection interval is usually set at half the number of flights at which engineers think a problem will develop. The inspection limit now is 11,000 "cycles," or engine start-ups and shutdowns. Experts said that one likely outcome was that the government would require inspections at shorter intervals.
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Originally Posted by jondc9
I recall a british air tours 737 that had an uncontained failure causing a fire , great damage and loss of life. type of engine was a pratt & whitney JT8d-?(15 or 17 or 9?).
I cannot recall what part of the engine broke apart, whether it was the compressor section or the turbine section...
I cannot recall what part of the engine broke apart, whether it was the compressor section or the turbine section...
Originally Posted by barit1
Jon's looking for this one. In this case it was the combustor--folks seem to forget the region between the HPC and HPT is a pressure vessel containing several hundred psi.