Command Trainer 43 was a holographic program used for training purposes aboard the USS Cerritos. It was a more advanced-level program than the Command Trainer 4 program.
It was used to train new command division officers for service on the bridge of a starship. The program placed the trainee in command of the vessel as it encountered a temporal rift. The trainee was expected to issue the appropriate orders to address the situation and save the ship and her crew.
In 2380, Ensign Sam Rutherford used the program under the supervision of Commander Jack Ransom while the former was considering changing careers to the command division from engineering. Rutherford became flustered and unable to issue orders to the crew, resulting in injuries and the destruction of the ship. The holodeck computer informed Rutherford that he had killed 105% of the crew. Ransom opined that Rutherford should have used the Janeway Protocol to address the situation, although Rutherford was unaware of what that protocol entailed. (LD: "Envoys")