The aircraft crashed off Apo island in Negros Oriental on Feb. 22, killing all 10 American military personnel on board.
Only three bodies have been recovered and the cause of the crash has not been established.
In a statement, the US military said Jon Steen, a Dutch-owned search and rescue ship based in Singapore and contracted by the US military, arrived at the crash site last Monday to begin salvage work.
"This effort is to determine the cause of the mishap as well as to prevent similar mishaps in the future," read the statement. "We will take the time needed to accomplish the mission."
Maj. Cynthia Teramae, spokeswoman for the US Special Operations Command Task Force 510, said the search and rescue experts are using the latest technological advances like the Deep Drone Remote Operated Vehicle (ROV) and the Shallow Water Intermediate Search System (SWISS).
"Both are owned by and operated by the Naval Sea Systems Command (NAVSEA) based in Washington, DC," she said.
The approximately 9 by 3 feet long Deep Drone ROV has auto control functions for complete freedom movement, while the SWISS is dual frequency side scan sonar that measures 3 by 6 inches and towed behind a vessel that produces detailed images of the ocean floor, Teramae added.
The Americans started using high technological equipment after they failed to recover most of the helicopter’s debris from the crash site.
Until now, US military investigators have not determined the cause of the crash.
The Chinook crashed at night while returning from Basilan to its temporary base in Mactan, Cebu. – Roel Pareño, AFP