Pilot confusion over which engine partially lost power after takeoff led to the crash of a Transair cargo jet off the coast of Hawaii in the summer of 2021, according to a final investigation report from the National Transportation Safety Board.

The captain and co-pilot noticed a partial loss of thrust in the right engine shortly after takeoff from the Honolulu airport, but a mix-up under the stress of emergency procedures caused them to rely on the damaged engine for power instead of the good left engine that would have enabled them to safely fly back, the report, issued Thursday, said.

The flight crew ditched the Boeing 737-200 freighter, operated by Rhoades Aviation under the name Transair, into the Pacific Ocean off Oahu about 11.5 minutes after departure. The captain sustained serious injuries while the first officer was relatively unscathed.

The aircraft took off at about 1:30 a.m. July 21, 2021, on what was to be the first of six flight legs that day within the Hawaiian Islands.

The pilots heard a thud as their plane climbed to about 390 feet. The captain declared an emergency as the first officer leveled off at about 2,000 feet but was unaware the first officer had reduced thrust in both engines because he was busy contacting air traffic control, according to the report. 

About three minutes later, the captain assumed control of the 737-200. At the time, the aircraft’s altitude had decreased to 1,690 feet. The first officer then informed the captain that the left engine was “gone,” but the captain didn’t verify the information and pushed the right thrust lever so the plane could maintain airspeed and altitude, the investigation found.

As the first officer went through the engine shutdown checklist he informed the captain that the engine gas temperature was beyond the “red” zone and thrust should be reduced on the right engine, at which point the captain decided to return to the airport. 

The plane continued to lose altitude and airspeed, but the crew neglected to shut down the right engine, as called for in training manuals, in an effort to keep the plane flying, the report said. Meanwhile, the crew kept the left engine at near idle position instead of increasing its thrust.

The captain then told the controller that “we’ve lost number one [left] engine. … There’s a chance we’re gonna lose the other engine too. It’s running very hot. … We’re pretty low on the speed, it doesn’t look good out here.” The report said the captain also urged the controller to notify the U.S. Coast Guard because he was anticipating a water landing. 

The high-temperature readings in the right engine made the flight crew think that a dual-engine failure was imminent, according to investigators. 

The NTSB said the captain spent too much time trying to contact air traffic control and explain the emergency instead of entering a squawk code into the transponder and focusing on stabilizing the aircraft before engaging in further radio communication. That distraction proved crucial in misidentifying which engine was failing. 

During a postaccident interview, the captain stated that he was unaware the first officer had reduced the left engine thrust to near flight idle. 

Investigators said the first officer’s high workload as he tried to manage the emergency and exchange tasks with the captain caused him to forget that he initially had verbalized that the right engine had lost power.

“If the captain had thought to test the thrust on the left engine by advancing the left thrust lever, the flight crew would likely have noticed an increase in left engine thrust, a yaw to the right, and engine sounds indicating that the left engine was capable of producing normal power,” the report concluded.

Investigators found two fractured turbine blades in the right engine, suggesting a stress rupture caused by oxidation and corrosion.

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