A380 engine failure - Qantas
Join Date: Jun 2010
Location: Brisbane, Australia
Posts: 304
Likes: 0
Received 0 Likes
on
0 Posts
For me as an operator...
these things happen....though not expected this early in their service life.
following the uncontained failure of the #2, with the accompanying debris shower of the area between #1 and #2, evidenced by the damage (internally and externally) shown in the leading edge area,
my concern here is that, had that debris shower damaged #1 in some way, either in a control system or causing an engine fire. My take of the events following the landing with regard to shutting down #1 engine, is that they had, in fact, no way of shutting off the fuel supply to that engine at any time post the #2 engine failure....and for me, that's scary stuff!
the 737NG has alternate paths for fuel shutoff controls to each engine...
EW73
these things happen....though not expected this early in their service life.
following the uncontained failure of the #2, with the accompanying debris shower of the area between #1 and #2, evidenced by the damage (internally and externally) shown in the leading edge area,
my concern here is that, had that debris shower damaged #1 in some way, either in a control system or causing an engine fire. My take of the events following the landing with regard to shutting down #1 engine, is that they had, in fact, no way of shutting off the fuel supply to that engine at any time post the #2 engine failure....and for me, that's scary stuff!
the 737NG has alternate paths for fuel shutoff controls to each engine...
EW73
I take it that the specific impulse would be measured in some reasonable unit like Newton metres, or foot pounds?
Or maybe, it's more like a KE thing?
Or is it a Joules thing? It's been a while since last I was in Mr Stirlings physics class.
Or maybe, it's more like a KE thing?
Or is it a Joules thing? It's been a while since last I was in Mr Stirlings physics class.
For the more common expression you might try
KE= 1/2 * Polar moment of inertia * rotational speed squared.
If I told you 1 million or 10 million foot-lbs would it make any difference?
It's sure to go through anything on the airplane that gets in its way
Guest
Posts: n/a
Ah.......Fun with physics! No problemo.
I know that there is sweet fa that can contain a broken turbine wheel, thus the red line marked adjacent on old 'Century series' US warplanes.
Just wonder how many much wallop is contained within?
Like a car at 70? prolly too little.
Like a train at 70? nope, that would be more.
Like superman, trying to catch a four ton truck, loaded with Kryptonite? maybe....
I know that there is sweet fa that can contain a broken turbine wheel, thus the red line marked adjacent on old 'Century series' US warplanes.
Just wonder how many much wallop is contained within?
Like a car at 70? prolly too little.
Like a train at 70? nope, that would be more.
Like superman, trying to catch a four ton truck, loaded with Kryptonite? maybe....
Join Date: May 2009
Location: sfo
Age: 70
Posts: 309
Likes: 0
Received 0 Likes
on
0 Posts
Anyone want to speculate on repair costs?
Since there haven't been any pictures of damage to the lower wing skin, I'm wondering if this wing needs to be partially re-skinned, wouldn't it need to be done in a factory jig, and would Airbus be able to interrupt the production line to do it? And at what cost? What sort of a field repair is necessary to fly it back to Toulouse? Will this aircraft be back in service within a year?
Join Date: Sep 2010
Location: earth
Posts: 1,341
Likes: 0
Received 0 Likes
on
0 Posts
Anyone want to speculate on repair costs?
Guest
Posts: n/a
My thought was the fail probability was more like 10 (-9). Oh well, at some point, it was 1/1.
barbiesboyfriend re: sequence/failure. My feeling is that this was not blade fail. The trail of lunch is more likely to be a start/failed disc, with its segments most likely retaining blades (if but for a millisecond). Then again if the disc migrated aft, the blades could have severed clean to start the cascade: debris/fail/debris/FAIL . Sioux City (UAL) was such a failure. The disc (why do I remember it was N1?) parted at an existing crack, and the conspiracists claimed the crack had been identified at a C check, but determined to be "within limits" (sic).
Since the entire midsection of this large powerplant is reported "missing", the shaft failed completely, and it is a wonder and a testimonial to RR that nothing more than a one hundred million dollar event needs to be expensed.
I don't think billet/forging/annealing or existing metallurgical defect is at play here. It seems more likely at this point, given the AD's that addressed the specific location of most likely failure, that it is a maintenance/inspection issue. The lubrication flow problem and required inspections, mitigations fall into an easy line of thought. Who wants to borescope this monster? Who else wants to STRIP it? It doesn't get any more remote than this junction to expose a potential million dollar repair. 400 cycles? that is a very pressurized demand on maintenance. For a New Engine? The implications are falling into place as we post. No one wants to be the bloke with the stick at the Hornet's nest. Given the AD(s), and I'm no expert, the (possible) dire consequences for the fleet are incalculable imo.
Let's capitalize the "Q" as well, it is a proper noun.
bear
barbiesboyfriend re: sequence/failure. My feeling is that this was not blade fail. The trail of lunch is more likely to be a start/failed disc, with its segments most likely retaining blades (if but for a millisecond). Then again if the disc migrated aft, the blades could have severed clean to start the cascade: debris/fail/debris/FAIL . Sioux City (UAL) was such a failure. The disc (why do I remember it was N1?) parted at an existing crack, and the conspiracists claimed the crack had been identified at a C check, but determined to be "within limits" (sic).
Since the entire midsection of this large powerplant is reported "missing", the shaft failed completely, and it is a wonder and a testimonial to RR that nothing more than a one hundred million dollar event needs to be expensed.
I don't think billet/forging/annealing or existing metallurgical defect is at play here. It seems more likely at this point, given the AD's that addressed the specific location of most likely failure, that it is a maintenance/inspection issue. The lubrication flow problem and required inspections, mitigations fall into an easy line of thought. Who wants to borescope this monster? Who else wants to STRIP it? It doesn't get any more remote than this junction to expose a potential million dollar repair. 400 cycles? that is a very pressurized demand on maintenance. For a New Engine? The implications are falling into place as we post. No one wants to be the bloke with the stick at the Hornet's nest. Given the AD(s), and I'm no expert, the (possible) dire consequences for the fleet are incalculable imo.
Let's capitalize the "Q" as well, it is a proper noun.
bear
My thought was the fail probability was more like 10 (-9). Oh well, at some point, it was 1/1.
The design intent was zero and as such the future expectation must be brought back into compliance under Continued Airworthiness regulation.
The so called 10 (-9) numbers only apply to combinations of aircraft systems and specfically exclude any system like engines which have their own standards e.g. Part 33 regs
Join Date: Feb 2008
Location: Wingham NSW Australia
Age: 83
Posts: 1,343
Likes: 0
Received 0 Likes
on
0 Posts
China-Memphis v's Beijing - Memphis
3pointlanding. What is the point of your post regarding China - Memphis v's Beijing - Memphis? Last time I checked Beijing was in China. As for SFC of American engines v's British engines I believe the RR's hold their SFC efficiency longer through the life of the engine.
Join Date: Feb 2004
Location: Australia
Posts: 1,307
Likes: 0
Received 0 Likes
on
0 Posts
the 737NG has alternate paths for fuel shutoff controls to each engine...
From what I've heard, a person could squeeze through the hole in the A380 wing, so it's likely that more than a single wiring loom was damaged (most aircraft front spar wiring runs parallel to each other).
Join Date: May 2002
Location: BNE
Posts: 256
Likes: 0
Received 0 Likes
on
0 Posts
The 737 classic runs one harness from the wing root along the front spar to the spar valve. The second harness runs along the rear spar out to the wing tip, through the wing and then back inboard along the forward spar to the spar valve.
The 800 rather than run the harness along the whole rear spar they took a short cut and ran it through the pylon fairing.
The 800 rather than run the harness along the whole rear spar they took a short cut and ran it through the pylon fairing.
Join Date: Apr 2010
Location: Alexandria VA USA
Posts: 40
Likes: 0
Received 0 Likes
on
0 Posts
So back to the topic at hand. It seems the green hydraulic system failed, a logical conclusion given the catastrophic failure of the #2 engine and possible loss of fluid from that location. So, this would seem to indicate severe damage to that system from shrapnal or the complete destruction of one of the two engine driven hydralic pumps on #2. Correct? Also baffling to me is that there seems to be no isolation valves within the hydraulic system (other than the fire valve). Am I correct to assume that any leak in either of the primary systems leads to a loss of the system? Also interesting to me is that the nose gear steering is not triple redundant. If you lose the green system (which appears to be the case here), you only have the electro hydaulics to fall back on. Pardon the sophomoric questions but I find the though that goes into these designs fascinating.
-Old Ag
-Old Ag
Join Date: Feb 2005
Location: flyover country USA
Age: 82
Posts: 4,579
Likes: 0
Received 0 Likes
on
0 Posts
I don't have specific numbers, but one engineer friend once compared the fragments of a failed turbine disc (of a RB211 or CF6 for example), as having the mass and velocity of a cannon ball. Good Luck in trying to protect the plane from such damage.
And every engine manufacturer has had more than a few such failures over the decades. There are several possible causes, which the metallurgical people are adept at sorting out.
First - most obvious - is overspeed. In that case, the reason for the overspeed must be nailed down, and/or an overlay control system installed to provide redundancy. Think of a helicopter engine encountering a geartrain failure in the helo transmission. Without such loss-of-load protection, the gear failure induces a overspeed in the engine.
Second - overtemperature operation can degrade the material properties to the point that the disc (or shaft) cannot sustain normal operating loads. (This is what happened in the collapse of the WTC towers on 9/11).
Third - a material defect in the disc may not be detected for a few hundred or many thousands of start/stop cycles - until it finally lets go. This is called Low Cycle Fatigue or LCF. A huge amount of quality inspection and process control goes into disc manufacturing, and the state of the art improves year-by-year. Even so, the predicted safe life (in cycles) becomes part of the certification standards; once a highly-stressed prime-reliable part reaches its LCF limit, it must be scrapped and replaced.
Hope this helps.
And every engine manufacturer has had more than a few such failures over the decades. There are several possible causes, which the metallurgical people are adept at sorting out.
First - most obvious - is overspeed. In that case, the reason for the overspeed must be nailed down, and/or an overlay control system installed to provide redundancy. Think of a helicopter engine encountering a geartrain failure in the helo transmission. Without such loss-of-load protection, the gear failure induces a overspeed in the engine.
Second - overtemperature operation can degrade the material properties to the point that the disc (or shaft) cannot sustain normal operating loads. (This is what happened in the collapse of the WTC towers on 9/11).
Third - a material defect in the disc may not be detected for a few hundred or many thousands of start/stop cycles - until it finally lets go. This is called Low Cycle Fatigue or LCF. A huge amount of quality inspection and process control goes into disc manufacturing, and the state of the art improves year-by-year. Even so, the predicted safe life (in cycles) becomes part of the certification standards; once a highly-stressed prime-reliable part reaches its LCF limit, it must be scrapped and replaced.
Hope this helps.
Join Date: Mar 1999
Location: Australia
Posts: 19
Likes: 0
Received 0 Likes
on
0 Posts
Why is QF still grounded while LH & SQ are flying?
Without bashing any airline, can anyone knowledgeable comment on why SQ was at first reluctant to do any checks on their fleet of 11 A380, then at RR's recommendation, inspected the fleet but were flying 12 hours later with a "Fleet checked" impression given.
I understand a full boroscope is about 8 hours to complete.
QF has found a further 2 engines worthy of removal and stripdown.
Does this indicate that SQ/LH believe the 970/972 differences are sufficient to "protect" them, or that SQ in particular (LH's hours are so low at this stage that theirs was probably a fair call) believe it is a QF maintenance issue rather than a design or manufacturing issue?
Anyone care to comment whether the #2/#3 engines showing up as worthy of inspection indicates that reverse thrust may be a factor?
(Not a reporter. Worked 14 years in the industry in Avionics and overhaul)
Cheers
I understand a full boroscope is about 8 hours to complete.
QF has found a further 2 engines worthy of removal and stripdown.
Does this indicate that SQ/LH believe the 970/972 differences are sufficient to "protect" them, or that SQ in particular (LH's hours are so low at this stage that theirs was probably a fair call) believe it is a QF maintenance issue rather than a design or manufacturing issue?
Anyone care to comment whether the #2/#3 engines showing up as worthy of inspection indicates that reverse thrust may be a factor?
(Not a reporter. Worked 14 years in the industry in Avionics and overhaul)
Cheers
