The U.S. Navy is changing up its personnel and policies after two deadly accidents in the Pacific occurred in less than two months.
Two senior commanders – Rear Adm. Charles Williams and Capt. Jeffrey Bennett – were fired this week as the Navy’s top officer prepares to testify on Capitol Hill Wednesday about the crashes. Vice Adm. Joseph Aucoin was relieved of his duties last month.
In the wake of the accidents, Vice Adm. Tom Rowden recommended eliminating five-hour watches to have more well-rested crewmembers, according to a memo obtained by Fox News. He also recommended ships keep automatic identification systems on, which would alert merchant boats of their presence.
Read on for a look at the recent U.S. military incidents in the Pacific.
USS John S. McCain
The guided-missile destroyer USS John S. McCain collided with the merchant vessel Alnic MC at approximately 6:24 a.m. Japan Standard Time, or 5:24 p.m. EDT on Aug. 20, according to the Department of Defense.
No one onboard the 600-foot oil and chemical tanker was injured, the Singapore government said, although the ship did sustain damage to a compartment at its front.
The McCain had been heading to Singapore on a routine port visit after conducting a sensitive freedom-of-navigation operation last week by sailing near one of China's man-made islands in the South China Sea. Five sailors were injured; 10 sailors were initially missing, but their remains have been found.
There was no immediate explanation for the collision, and the Navy said an investigation would be conducted. Singapore, at the southernmost tip of the Malay Peninsula, is one of the world's busiest ports and a U.S. ally, with its naval base regularly visited by American warships.
Despite reports to the contrary, multiple Navy officials told Fox News that a cyberattack played “no role” in the ships’ collision.
UH-60 Black Hawk helicopter
Officials ended the search Monday for the five soldiers aboard an Army Black Hawk helicopter that crashed in the ocean off the coast of Hawaii on Aug. 15.
Two Black Hawk aircrews were participating in training exercises when communications were lost.
Crews from the Army, Coast Guard, Navy and local agencies in Hawaii searched around the clock as strong currents moved the wreckage into a deep-water search area that spanned 72,000 nautical miles.
The missing soldiers range in age from 26 to 41. The crew did have life vests and devices to assist with underwater breathing on the helicopter, officials said.
But while officials recovered significant debris from the crash, Army and Coast Guard officials said Monday that they found no signs of life and ended the search-and-rescue operation.
Three U.S. Marines were declared dead in August after their MV-22 Osprey crashed off the coast of Australia.
The MV-22 Osprey – part helicopter, part plane – crashed into the back of the USS Green Bay, a Navy amphibious ship, and fell into the sea on Aug. 5.
Seven sailors – ranging in ages from 19 to 37 – died in June when the USS Fitzgerald collided with a container ship in waters off Japan.
“The collision was avoidable and both ships demonstrated poor seamanship,” the U.S. Navy’s 7th Fleet said in a statement. “Within Fitzgerald, flawed watch stander teamwork and inadequate leadership contributed to the collision that claimed the lives of seven Fitzgerald sailors, injured three more, and damaged both ships.”
The captain of the Philippine-flagged container ship accused the Navy destroyer of failing to heed warning signs before the crash on June 17.
USS Lake Champlain
The USS Lake Champlain, a guided-missile cruiser part of the U.S. Navy’s 7th fleet, collided with a South Korean fishing vessel in the Sea of Japan in May.
No injuries were reported following the May 9 crash.
The naval ship was conducting routine operations in international waters at the time of the incident, according to the U.S. Navy. A defense official said visibility was limited at the time.
The ballistic-missile submarine USS Louisiana collided with a U.S. Navy Offshore Support Vessel off the coast of Washington state on Aug. 18, 2016, according to the U.S. Navy.
The crash occurred during routine operations in the Strait of Juan de Fuca.
While both vessels were damaged, no one was injured in the collision.
The Associated Press contributed to this report.
Kaitlyn Schallhorn is a Reporter for Fox News. Follow her on Twitter @K_Schallhorn.