Officials instruct all USN ships to 'exercise caution' when using digital nautical charts in coastal areas

US Navy (USN) officials are directing all ship crews to "exercise caution" when using digital nautical charts (DNCs) supplied by the National Geospatial-Intelligence Agency (NGA) in coastal areas and to also employ multiple sources of navigational data, a source told IHS Jane's on 29 January.

The fleetwide instruction comes on the heels of the 17 January grounding of a USN minesweeper in the Philippines nearly two weeks ago.

USS Guardian (MCM-5) remains stuck on Tubbataha Reef, approximately 80 miles east-southeast of Palawan Island. The incident is still under investigation, but one potential cause has been linked to a DNC that contained erroneous data of the reef's location.

USN officials previously announced that the NGA had contacted them about the faulty chart shortly after the incident occurred. The NGA told IHS Jane's that the error had been addressed and that a comprehensive review of all other DNCs had resulted in the discovery of only one other error of similar magnitude: incorrect data derived from commercial satellite imagery had rotated the placement of the southern coast of Chile towards the sea on both the paper chart and the DNC of the region.