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Lockheed Martin Littoral Combat Ship - Problems

The effective combination of the output of driving engines on to one propeller shaft is accomplished by means of combining gears which are generally designed in the manner of so-called parallel-shaft gearing, that means gears having parallel axes.

As of 20 January 2021 the Navy discontinued further deliveries of Lockheed Martin’s Freedom-class littoral combat ship until a material defect found in the warship’s combining gear can be fixed. According to the Navy, the defect affected the complex transmission that transmits power generated by the ship’s engines to its waterjet propulsion system. Rear Adm. Casey Moton, the head of the unmanned and small combatants office at Naval Sea Systems Command, said a modified version of the combining gear, which is still under development, will undergo extensive factory and sea-based testing before it is accepted and installed in-service, Defense News reported. The developer of the defective combining gear, German firm RENK, worked with service officials and Lockheed Martin to develop a fix, which could take months to install on each ship.

On 08 January 2021 the Navy announced plans to award a firm fixed price type contract based on only one responsible source that will satisfy agency requirements for Littoral Combat Ship (LCS) Combining Gear, from Original Equipment Manufacturer (OEM) RENK Systems Corporation under other than full and open competition. This posting fulfills the requirements set forth in FAR 5.202 and served as sources sought and synopsis of a proposed contract action.

The STBD Combining Gear is the main driving force for the ships propulsion and without this emergent repair, as a result the ship is inoperative. To complete the repair, replacement material can only be acquired through OEM, Renk Systems Corporation. During disassembly of the STBD Combining Gear, the Original Equipment Manufacturer (OEM) RENK Systems Corp. identified the output shaft and bearings G1, G2, G3 were not required to be removed as part of the STBD Combining Gear disassemble. However, based on the damaged condition of the removed GT input shaft, Idler Gear, Low Speed and High Speed shafts and the associated 13 bearings, it is expected that the output shaft and bearings are damaged as well. OEM Renk Systems Corporation has recommended that the output shaft and bearings be replaced.

RENK AG is the world leader in the design and manufacture of advanced reduction gear systems for combined propulsion systems supplied to the US Navy's Freedom-Class and Independence-Class Littoral Combat Ships and the Coast Guard's National Security Cutter. In addition, RENK supplies reduction gears for other naval and commercial vessels and yachts, and has more than four hundred installations in thirty naval fleets around the world. RENK supports these programs with training, maintenance and repair services, and spare parts supply. RENK AG has been named the "2014 Littoral Ship Program Supplier of the Year" by the Lockheed Martin Littoral Combat Ships (LCS) industry team in recognition of RENK's successful and productive relationship with the ship-design and contract-management company.

The Navy attributed a series of recent engineering casualties on delivered LCS to shortfalls in crew training, seaframe design, and construction quality. According to the Navy, these failures have resulted in substantial downtime and costs for repairs or replacements. The LCS have both diesel and gas turbine engines. The combining gear is a complex set of gears which “combines” the output from the ship’s Rolls Royce MT-30 gas turbines and Colt-Pielstick diesel engines to the ship’s water jets. By 2014 changes had been or would be made to improve maintainability on LCS 1 and 3. The design will be changed on LCS 5 and follow-on ships to further improve maintainability.

While operating USS MILWAUKEE (LCS 5) on all four engines at full power during transit in the Atlantic in December 2015, an emergency stop of the gas turbine engines led to excessive wear of the high speed clutch causing damage to the high speed clutch and combining gear. Root cause analysis is in progress, but the combining gear on LCS 5 and follow is a new design (prior manufacturer ceased operations), and changes to the control logic for the de-clutch sequence and clutch piston release speed associated with the new design are apparent causes. Design modifications based on root causes have been developed and are being tested by Lockheed Martin and RENK (the gear manufacturer), in parallel with ongoing root cause analysis efforts. Pending satisfactory testing this month (December 2016), the associated high speed clutch modifications and machinery control software updates will be applied to LCS 9 and follow prior to delivery and LCS 5 and 7 during their Post Shakedown Availabilities (PSAs). LCS 1 and LCS 3 gear sets were not affected.

USS FORT WORTH (LCS 3) ( "FTW") experienced a casuaity resulting in damage to her port and starboard combining gears (CG). Crew 101 conducted an OPTEST on the Main Propulsion Diesel Engines (MPDEs). At the time the MPDEs were started, the Combining Gear [CG] lube oil system was not aligned. The misalignment of the lube oil system resulted in high temperatures which damaged the CGs. The principal cause of the damage to the CGs was a failure to follow written procedures. Full procedural compliance would have informed Crew 101 that the CG lube oil system was misaligned. Furthermore, failure to follow the Chief Engineer's Standing Orders by having a reduced volume on the MPCMS alarm system prevented the crew from responding quickly to the situation added to the damage. Lastly, the lack of effective leadership, fatigue, frustration, lack of experience, and failure to utilize external support were all factors that contributed to the casualty.

Following completion of PORT MPDE injector work by contracted maintenance personnel on 11 January 2016, FTW experienced numerous fuel leaks from the injectors when the head tank was aligned requiring them to tag the MPDE back out to tighten the associated connectors and clean up the resul tant fuel spill.

The ship was originally scheduled to get underway for Hong Kong on 12 January 2016 but the date was moved later to accommodate SSDG repairs and was not firm at the time of the casualty. This date was slipping day for day to complete repairs on the SSDGs. The CO and XO acknowledged they were feeling a "tremendous amount of pressure" from the operational chain of command to get underway . The CO stated, if necessary, he was prepared to tell the DESRON 7 Commodore he could not get underway safely on time to meet the Hong Kong commitment. LCSRON attributed Crew 101's struggles to lack of watchstander itiative and inability to adhere to basic watchstander principles.

Normally the ship's CG lube oil system is already aligned before attempting to start MPDEs (when the ship is underway or auxiliary steaming). Crew 101 was therefore not experienced with starting MPDEs in a cold iron condition. Crewmembers expressed being exhausted and under heavy workloads, with several competing demands for their attention, in the days leading up to the CG casualty.

On 12 Jan 2016, the crewe began lighting off both MPDEs at the same time. The procedure did not allow for this, but it was common practice to save time. The crew attempted to start PORT MPDE, but it failed to start due to the barring device being engaged - the MCMS showed it disengaged. The input pinions to the combining gear rotate when engines are started locally. ) received a high bearing temperature alarm, but failed to take action. Upon receiving the bearing alarm, the crewe checked shaft rotation (none existed), clutches (none engaged) and CG LO temperature (green) and therefore assumed the hot bearing indication was a problem with a canon plug or the circuit card that had recently changed some bearing setpoints. The crewe had no prior knowledge that the MPDE input shaft rotated inside the combining gear without the clutch engaged.

Most of the rekevant crew did not understad that a bearing temperature that rises rapidly and then falls rapidly indicates a wiped bearing, though when given the question in a hypothetical underway situation, some answered correctly. A few did not understand what a wiped bearing is. Both Combining Gears were run without lube oil. On 6 June 2015, 500 gallons of lube oil was spilled to the bilge. The command conducted a preliminary investigation, but failed to determine the cause of the spill.

The Pacific Fleet Command investigation of 14 September 2016 into the Combining Gear casualty on USS Fort Worth (LCS 3) on 12 Januayr 2016 found that "This mishap resulted from fundamental lapses in procedural compliance and watchstanding, which includes proper oversight and management of assigned subordinates in the engineering department.... The leadership of Crew 101 was unable to adequately resolve issues. Multiple events occurred from June 2015 up to the casualty. In each case, the leadership failed to determine the root causes and effectively correct them .... As with most mishaps, a series of factors often contribute to failure. This mishap is no different. A fundamental lack of procedural compliance was the principal cause but contributing factors included: a lack of effective leadership; a culture of complacency and overconfidence by some members of Crew 101 combined with a lack of experience and expertise; and a systemic failure to effectively arid completely resolve deficiencies. The investigation, supplemental investigation and endorsements adequately capture the proximate issues and co11'ective actions.... most importantly, both the parent ISIC and the operational !SIC recognized they had a Crew whose perfmmance was below that expected of a deployed unit and little to no mitigating actions were taken. It was not an issue of recognizing the performance but more of taking effective action to correct it."

The Investigation recommended that "PEO replace the current lsotta-Fraschini SSDG models on LCS 1 and 3 with either the upgraded models installed on LCS 5 and above, or with SSDGs that are more reliable and less maintenance intensive (e.g., MTU or Caterpillar) . In the interim, increase the level of focus on the existing models to include more frequent grooms before and during deployment."

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Page last modified: 01-07-2021 14:52:38 ZULU