I’m sure by now everyone has heard that the Navy’s newest LCS, the
, suffered a breakdown just 20 days after being
commissioned and had to be towed back to port.
The cause appears to be fine metal filings in the lube oil system for
the combining/splitter gear assemblies. Repairs
will, reportedly, require several weeks or more. Milwaukee
What has not been reported is that the recent breakdown of the LCS Milwaukee due to metal filings in the lube oil system may have had its origins in an earlier incident during construction and the current breakdown may have been avoidable. Here’s a description of the May 2015 construction incident as provided by Defense News website (1).
“The Milwaukee had been aiming for a delivery date in August, but that's been delayed at least a month by a shipyard accident that took place in late May in the midst of builder's sea trials — a series of underway periods where the shipyard checks out the ship before the Navy runs acceptance trials. …
The accident took place late one evening as the ship was pierside in Marinette, trying to get ready to head back out in the morning.
‘We were basically looking at cleaning up a lube oil system,’ North [Joe North, Lockheed's vice president of Littoral Ships and Systems] explained. ‘We had an inadvertent start of the turbine that went to the gear that spun the starboard shaft in the machinery plant between the splitter gear and the forward gear.’ The shaft should have been decoupled so the turbine wouldn't turn it. ‘So with no lube oil there, that is not the way you want to run it. It was a very, very short time frame, less than a minute.’
But it was long enough to damage the splitter gear, shaft bearings and other parts.
‘We were actually pretty fortunate there wasn't a whole lot of damage in there,’ North said. ‘There were a lot of parts that might have been scored or something or marked. We had them remachined, brought back in, put the gear back together.’
Repairs have been completed, he said, and crews were putting all the pieces back together to resume sea trials.
While the investigation is still being completed, North acknowledged the accident was the shipyard's fault.
‘It was a procedural error, human error,’ he said.
The Navy is right in the middle of overseeing the repair work.
‘We are pleased on the Navy side with the work we are seeing and the progress that is being made,’ Rear Adm. Brian Antonio, program executive officer for the LCS, said July 17 at the shipyard. ‘I actually went down into the space and things are being put back together again. The shipyard is doing the welding and the testing required to put the ship back to where it was prior to the casualty.’ “
So, we have a construction incident in which the splitter gear and other equipment was damaged by being run without lube oil. The operation of the gears (metal on metal) undoubtedly produced metal filings in the splitter/combining gear assemblies. It seems quite likely that the current breakdown due to metal filings in the splitter/combining gear assemblies originated from the earlier construction incident. It appears that the earlier construction incident produced metal filings that were not cleaned out from the splitter/combining gear system and those filings eventually accumulated in the splitter/combining gear lube oil system, clogging the filters, and shutting the system down.
|LCS Splitter/Combining Gear System|
If true, this raises a lot of questions. Why wasn’t the earlier incident properly repaired? Any engineer would have known there would be metal filings present in the system after the incident. Why weren’t they cleaned out?
Knowing that there had been an earlier incident, why didn’t the Navy insist on much closer inspection of the lube oil systems? The filings were there the whole time and would have been readily evident on closer inspection.
Rear Adm. Antonio went into the engine space. Perhaps he should have sent an engineer into the space instead of conducting a public relations exercise that accomplished nothing. What was he going to see? Nothing.
The Freedom class has a history of engineering/propulsion system breakdowns including lube oil system issues. Why wasn’t particular attention paid to the
’s system in light of the general class history of
problems and the specific construction incident? Milwaukee
Let me be quite clear about this report. This is my speculation and the link between the construction incident and the recent breakdown is not confirmed. It is based only on a logical assessment of the public information. However, if the two incidents are not related, the co-incidence is astounding.
Further, if the two incidents are related the manufacturer should be responsible for the entire cost of this breakdown.
Finally, if related, this yet again demonstrates the Navy’s utter lack of in-house engineering competency and oversight of ship construction.
(1)Defense News, “LCS Hits Its Stride in Marinette”, Christopher P. Cavas,
July 26, 2015,
I wonder if after the 'inadvertent' start they just ran the lube oil system and did not find any metal filings but when they then went out into the Atlantic the sea state bounced things up and down enough that the filings got mixed into the lube oil and shut things downReplyDelete
I also wonder at the lack of redundancy which allows contamination caused by a failure of one gear box to shut down the entire propulsion system which requires the ship to be towed
Does anyone have any drawings of the entire propulsion system?
Also what happened with the Navy Oil Analysis Program (NOAP) ? They are suppose to take regular samples and special samples after any suspected damage. They can find even tiny amounts of material and even tell what it comes from by the different amounts of various contamination. For example they can tell if a bearing is going bad because it has specific materials in it which if found in the lube oil will point to wear and damage.Delete
Does the low manning LCS even take NOAP samples? Did the shipyard?
Good questions for which I have no answers.Delete
Are you reporting based on an actual examination of the gears, or just speculation? I ask this because in my experience that metal filing is a consequence, not a cause. Most likely was the gears were not machined correctly or incorrectly assembled. Removing too much material from teeth would cause the hammering on the tooth face. A second possibility was the bears were damages by vibrations in the gears. Either way, the problem did originate from the "accident" and as preventable with proper inspection, but I don't think the filings were left in the lube system when it reassembled.ReplyDelete
If you read the post, you saw this sentence,Delete
"This is my speculation and the link between the construction incident and the recent breakdown is not confirmed."
So, that answers your question.
The filings were the cause of the subsequent breakdown in that they clogged the lube oil filter. The question posed in the post, and answered by my speculation, is where the filings came from. It appears logical to assume they resulted from the original incident in which the gears were run dry.
You also saidDelete
"It appears that the earlier construction incident produced metal filings that were not cleaned out from the splitter/combining gear system and those filings eventually accumulated in the splitter/combining gear lube oil system, clogging the filters, and shutting the system down"
The problem with this is the assembly process calls for a flushing the complete lube oil system after the gear box is re installed. But that flushing will do nothing for any new filings created after the gearbox is put back in services. Which is why the filings found in the filter most likely were created during the run time after the Milwaukee was commissioned.
GLof, gotta disagree. If the filings were new, it means that there is a mis-toleranced fittings/gears that created new filings due to rubbing. If so, every LCS with the same gearing system would be suffering from filings in the system and that doesn't appear to be the case. No, the simplest explanation is the original filings never got cleaned out. While the reinstallation process may call for a complete flush/cleaning (do you know the process? do you have a written procedure for this or are you just speculating on what ought to be standard good practice?)it was probably just improperly done - just as the original incident should never have occurred but did. Design engineers can write all the procedures they want but if the hands-on guys don't follow them it won't make any difference.Delete
This one seems pretty clear.
If the parts were original cuts, (IE made with unworked metal)Then you be correct, but there is a give away in the press release.Delete
"North said.‘We were actually pretty fortunate there wasn't a whole lot of damage in there,’ North said. ‘There were a lot of parts that might have been scored or something or marked. We had them remachined, brought back in, put the gear back together.’"
That is when I think the damage was done. That why other gearboxs did not fall apart.
Oh as for my knowledge on gear boxes, it mostly with smaller industrial type that are normally replaces, not re built. But done my share of causal investigation for my employers back when, so I know about gear failures.
Ihe process of rebuild a marine gearbox come to me for a couple of oldtimers on naval discussion board, during one of JFK's major SUPSHIP inspection failure. They aim me toward a marine engineering handbook that I purchase a copy
of a read cover to cover.
GLof, remachining reduces the size of the part(s) being machined. That makes the tolerances larger (looser fit) and LESS likely to subsequently produce metal on metal filings because the metal is no longer rubbing on metal. So, where would the filings have come from?Delete
My interpretation is still the most logical.
I know you like to defend the LCS but this is not an indictment of the LCS. It's an indictment of the manufacturer's quality control and safety. It's an indictment of the Navy's NAVSEA group. It's an indictment of the Navy's engineering practices. It's not an indictment of the LCS. Nothing about the LCS, itself, caused this.
Accept the evidence and the logic until more or better information comes out.