The San Antonio (LPD 17) is a 684-foot, 25,000-ton vessel equipped with four sequentially turbocharged diesel engines. According to the Navy, it carries about 360 crewmembers and when deployed carries 900 troops. Built in Northrop Grummans shipyard in Avondale, La., it was commissioned in January 2006.

The Navys Fleet Forces Command earlier this year assigned Rear Adm. Michelle Howard the task of investigating diesel engine and related maintenance and quality assurance issues about the ship. Her report, dated May 20, came out July 1. The reports executive summary details a series of issues related to the ships lube oil systems.

One issue involved metal shavings in the lube oil system piping. A repair team in October 2008 conducted repairs to the main propulsion diesel engines lube oil service system piping due to failure of several welded joints. The repair included partial use of carbon steel piping.

According to the document, workers in June 2009 conducted permanent repairs, including replacement of about 80 percent of the existing external lube oil service piping with new stainless steel piping. After completion of the repairs, workers conducted a flush of the piping. However, as designed, the flushing procedure was inadequate to completely remove contaminants from the lube oil service system, the report observed.

In November and December 2009, the document states, Norfolk Ship Support Activity inspectors and San Antonio personnel discovered foreign matter – bits of stainless steel – in the lube oil service system for three of the four diesel engines. The investigation concluded that the probable source of the stainless steel was the byproducts of the production and installation of stainless steel lube oil service system piping. The cause of the stainless steel was potentially the result of poor weld joint fit up during new construction that created contaminate traps that could allow for an intermittent release of contaminates.

In November 2009, the Norfolk Ship Support Activity determined additional maintenance was required to address excessive crankshaft main bearing and thrust bearing wear in three of the four diesel engines. The damage wasnt related to the metal shavings found earlier in the lube oil service systems, they found. Bearing failure root cause is lube oil contamination that occurred during the ship building process to include all repairs and maintenance prior to the [planned maintenance availability].

In a Jan. 8, 2010, teleconference with other Navy officials, Naval Sea Systems Command suggested an alternate cause for the contamination that was causing bearing damage.

This hypothesis suggests that the lube oil contaminates that are circulated back to the [main propulsion diesel engine] via the self-cleaning pre-filter are continuously reduced in physical size by the [wearing away] action of the lube oil service pumps until the contaminates are small enough to pass through the filter and duplex strainers, the report detailed. Contaminates that pass through the filter and strainer complex could still be large enough to cause bearing damage. The Naval Sea Systems Command favored a modification to prevent contaminates from entering the diesel complex. It would do so by filtering out contamination discharged by the filter back to the sump.

The investigation determined that ships force was slow to recognize lube oil contamination for a variety of long term issues. Command leadership failed to effectively execute a basic engineering program, specifically the lube oil quality management program, which was determined to be ineffective, the report remarked.

The report also highlighted unacceptable conditions that produced the ships significant engineering problems. Inadequate government oversight during the construction process failed to prevent or identify as a problem the lack of cleanliness and quality assurance that resulted in contamination of closed systems, the investigation concluded. Materiel challenges with this ship and other ships of the class continue to negatively impact fleet operations.