Narrative:

Practicing engine failure prior to VMC. Was told to line up and wait. Student went full throttle and I ([the] instructor) failed the left engine at 25 kts. The student recovered by bringing both throttles to idle and got back to centerline. We have done this numerous times in the plane and in the sim. I then returned the left mixture to full rich. The student then went full throttle on the left engine. We shot off to the right very quickly. I called for flight controls and brought both throttles back to idle. The student didn't hear me call for controls and slammed [on] and locked up the brakes. I could not recover in time. [This] resulted in going off runway by putting our right main gear and nose wheel in the rocks. It resulted in a runway excursion and possible prop strike.what could have been done to prevent this was have a better brief of how to correct for this situation. I could have been closer on the controls to hopefully 'save' the plane and have it stay on the runway. I could have yelled my controls more clearly and loudly.

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Original NASA ASRS Text

Title: PA44 Instructor Pilot reported a runway excursion resulted when the student pilot lost directional control during engine-out takeoff practice.

Narrative: Practicing engine failure prior to VMC. Was told to line up and wait. Student went full throttle and I ([the] instructor) failed the left engine at 25 kts. The student recovered by bringing both throttles to idle and got back to centerline. We have done this numerous times in the plane and in the sim. I then returned the left mixture to full rich. The student then went full throttle on the left engine. We shot off to the right very quickly. I called for flight controls and brought both throttles back to idle. The student didn't hear me call for controls and slammed [on] and locked up the brakes. I could not recover in time. [This] resulted in going off Runway by putting our right main gear and nose wheel in the rocks. It resulted in a runway excursion and possible prop strike.What could have been done to prevent this was have a better brief of how to correct for this situation. I could have been closer on the controls to hopefully 'save' the plane and have it stay on the runway. I could have yelled my controls more clearly and loudly.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.