Narrative:

All pre-flight and start-up checklists were completed and coordinated normally. Our engine diagnostics never indicated anything other than completely normal indications. During the run-up all engine tests were; again; normal. During the automated and manual ecu swap and check both a&B ecus on both engines operated normally and without incident. After the pre-flight inspection was complete we started to taxi and completed a successful brake test on both pilot stations. The taxi was completed normally to the hold short line of runway 32. Initially 4 planes preceded us in the line to take-off. After a short wait; we were number 1 to takeoff. After making the proper call to CTAF we took our position on the runway threshold for takeoff. No aircraft were in the traffic pattern however 3 aircraft were within 5 miles of the airport - 2 departing southwest and 1 to the east. We held our brakes as we ran the throttles up to 100% on both engines. We noted our engines' temperatures; pressures and load percentage (100%) and heading were all normal and operational. Once satisfied; my student released his brakes and we began our takeoff roll. On the roll both the primary and standby airspeed came alive and I took another quick glance at the engine indications and again nothing abnormal was observed. Shortly after we began our takeoff roll I brought the left throttle to idle to simulate an engine failure on takeoff. My student immediately retarded the other throttle and applied right rudder to maintain center line. When I perform a simulated engine failure on takeoff I shadowed my student on the flight controls. Despite my student's timely and proper actions the aircraft still drifted left of runway center line. I quickly took controls and found that full deflection was applied on the right rudder and that the left propeller had stopped spinning. I quickly applied right brake to maintain center line and bring the airplane to a stop. While decelerating I made a call on CTAF and stated we had lost engine power on takeoff and I asked the C-210 holding short of the runway to continue holding short. He acknowledged and asked if we were ok. I replied and assured him we in fact [were] safe and I was trying to taxi clear of the active. I noted the engine master was still in the 'on' position. I recycled the engine master and then tried to restart the engine. The starter engaged however the engine never came online despite 3 attempts. I then began to taxi the aircraft. I tried to maintain a straight taxi however even with full right rudder and using the right brake to assist my effort I was not able to taxi straight. I then knew I had to make left circles in an effort to clear the runway off the the right at bravo 2. I was unable to line up straight for the taxiway so I aimed the aircraft to the right of the taxiway and went in between two runway edge lights. I came to a stop in the grass adjacent to the runway after I ensured my entire aircraft was clear of the runway by about 10 feet. I tried once more to restart the engine while clear of the runway - to no avail. I then shut down the right engine. I kept the avionics and radios online to continue making calls and report my status. Maintenance arrived shortly thereafter and towed the aircraft back to the hangar. The cause of the loss of power is still undetermined. During this occurrence no individuals were injured and [there was no damage to the] aircraft.

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Original NASA ASRS Text

Title: DA42 instructor pilot reported the left engine failed on the takeoff roll when the throttle was retarded to simulate an engine failure.

Narrative: All pre-flight and start-up checklists were completed and coordinated normally. Our engine diagnostics never indicated anything other than completely normal indications. During the run-up all engine tests were; again; normal. During the automated and manual ECU swap and check both A&B ECUs on both engines operated normally and without incident. After the pre-flight inspection was complete we started to taxi and completed a successful brake test on both pilot stations. The taxi was completed normally to the hold short line of Runway 32. Initially 4 planes preceded us in the line to take-off. After a short wait; we were number 1 to takeoff. After making the proper call to CTAF we took our position on the runway threshold for takeoff. No aircraft were in the traffic pattern however 3 aircraft were within 5 miles of the airport - 2 departing Southwest and 1 to the East. We held our brakes as we ran the throttles up to 100% on both engines. We noted our engines' temperatures; pressures and load percentage (100%) and heading were all normal and operational. Once satisfied; my student released his brakes and we began our takeoff roll. On the roll both the primary and standby airspeed came alive and I took another quick glance at the engine indications and again nothing abnormal was observed. Shortly after we began our takeoff roll I brought the left throttle to idle to simulate an engine failure on takeoff. My student immediately retarded the other throttle and applied right rudder to maintain center line. When I perform a simulated engine failure on takeoff I shadowed my student on the flight controls. Despite my student's timely and proper actions the aircraft still drifted left of runway center line. I quickly took controls and found that full deflection was applied on the right rudder and that the left propeller had stopped spinning. I quickly applied right brake to maintain center line and bring the airplane to a stop. While decelerating I made a call on CTAF and stated we had lost engine power on takeoff and I asked the C-210 holding short of the runway to continue holding short. He acknowledged and asked if we were ok. I replied and assured him we in fact [were] safe and I was trying to taxi clear of the active. I noted the Engine Master was still in the 'On' position. I recycled the engine master and then tried to restart the engine. The starter engaged however the engine never came online despite 3 attempts. I then began to taxi the aircraft. I tried to maintain a straight taxi however even with full right rudder and using the right brake to assist my effort I was not able to taxi straight. I then knew I had to make left circles in an effort to clear the runway off the the right at Bravo 2. I was unable to line up straight for the taxiway so I aimed the aircraft to the right of the taxiway and went in between two runway edge lights. I came to a stop in the grass adjacent to the runway after I ensured my entire aircraft was clear of the runway by about 10 feet. I tried once more to restart the engine while clear of the runway - to no avail. I then shut down the right engine. I kept the avionics and radios online to continue making calls and report my status. Maintenance arrived shortly thereafter and towed the aircraft back to the hangar. The cause of the loss of power is still undetermined. During this occurrence no individuals were injured and [there was no damage to the] aircraft.

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.