The small Hawaii-based cargo operator that lost one of its planes July 2 when the pilots were forced to ditch it into the ocean after it lost power had been under investigation since last fall for alleged maintenance violations.

Rhoades Aviation Inc. was grounded on Thursday by the Federal Aviation Administration, the agency said Friday in an emailed press release. The FAA action is separate from the investigation of the recent crash, the agency said.

The two pilots of the Boeing Co. 737-200 were rescued after they reported losing power in both engines while trying to return to the airport for an emergency landing.

“On June 13, the FAA notified Rhoades Aviation that the agency intended to rescind the authority for the airline to conduct maintenance inspections due to deficiencies identified during the investigation,” the FAA said in its release.

Losing that authority would prevent the airline from flying. The agency said it had been investigating “maintenance and safety practices.”

The National Transportation Safety Board hasn’t said whether maintenance of the 46-year-old jet is an issue in the crash, though the highly unusual apparent failure of two engines at the same time will prompt a thorough review of any work performed on them.

The NTSB announced July 9 that it had located the plane’s wreckage after an undersea search and was developing a plan to retrieve critical components, such as the engines, and the plane’s two crash-proof recorders. Investigators have also interviewed the pilots and 10 others, the NTSB said.

Shortly after takeoff from Daniel K. Inouye International Airport in Honolulu, pilots reported they had lost one of the plane’s two engines. As they circled back toward the airport, the situation worsened.

“We’re gonna lose the other engine too. It’s running very hot,” a pilot radioed to an air-traffic controller. “We’re low on the speed. It doesn’t look good.”

Rhoades, which operates as Transair, has one remaining plane, the FAA said. The company didn’t immediately respond to a request for comment before normal business hours.