From the Philippine News Agency (Aug 14): Misplaced reef in DNC caused USS Guardian grounding
http://www.pna.gov.ph/index.php?idn=1&sid=&nid=1&rid=555047
Now it can be told.
The Jan. 17 grounding of the USS Guardian, a minesweeper of the US Navy, can be attributed to the incorrect placement of a reef in the Philippine Islands by eight miles on its digital nautical charts.
US National Geospatial-Intelligence Agency director Letitia Long admitted this to a letter to US Navy Chief of Naval Operations Admiral Jonathan Greenert.
She added that the DNC display of the Tubbataha Reef in the Sulu Sea was wrong due to erroneous commercial satellite imagery.
Long, in her letter to Greenert, said NGA discovered that the charts related to the Tubbataha Reef prior to 2008 included a number of “phantom islands.”
To correct this problem, she said the NGA used commercial satellite imagery to update the charts.
“One of these images included incorrect information about the location of the section of ocean that includes the Tubbataha Reef. As a result, the reef was incorrectly placed in the [digital nautical chart],” Long said.
In 2011, NGA obtained survey data that corrected this positioning, but due to a failure to follow established procedure, this correction was made in one portion of the DNC, but not in another, Long said, a mistake she attributed to human error.
Long stressed that error was compounded by “exclusive reliance” of the USS Guardian crew on GPS as a “single source of navigation.”
The crew did not pay heed to lighthouses on the reef, according to a 160-page post-wreck investigation report by Admiral Cecil D. Haney, commander of US Pacific Fleet.
The US Navy report said the grounding and destruction of the minesweeper also highlighted “potential systemic issues” on ships that use the Navy’s computer based vessel management system and its electronic chart and display system.
The vessel management system is supposed to issue audible alerts of potential dangers, but as the USS Guardian neared the Tubbataha Reef before grounding, the Navy report said watchstanders on the bridge and in the combat information center did not report any alarms.
As the ship neared the reef, personnel on the bridge reported flashes from a lighthouse, but those were ignored as the crew continued to rely on the electronic charts and GPS.
Investigators blamed the grounding primarily on the crew’s failure to reconcile the differences between digital nautical charts of the area and more refined coastal charts.
The crew also failed to verify the position of the reef using a list of lighthouses.
The grounding broke the ship’s keel when rocks on the reef punched holes in its hull. The crew abandoned ship, with no loss of life.
“USS Guardian leadership and watch teams failed to adhere to prudent, safe, and sound navigation principles, which would have alerted them to approaching dangers with sufficient time to take mitigating action,” Haney said.
http://www.pna.gov.ph/index.php?idn=1&sid=&nid=1&rid=555047