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
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