PA-44 instructor pilot reported an engine failure led to a single engine approach and landing.

Attributes
ACN	1603466
Time
Date	201812
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Aircraft 1
Make Model Name	PA-44 Seminole/Turbo Seminole
Operating Under FAR Part	Part 91
Flight Phase	Climb
Route In Use	None
Flight Plan	None
Component
Aircraft Component	Engine
Person 1
Function	Instructor Pilot Not Flying
Qualification	Flight Crew Flight Instructor Flight Crew Commercial Flight Crew Instrument Flight Crew Multiengine
Experience	Flight Crew Last 90 Days 170 Flight Crew Total 800 Flight Crew Type 220
Events
Anomaly	Aircraft Equipment Problem Critical

Narrative:

I departed on a PA-44 training flight with a student. We did two laps in the pattern working on landings. After which we departed and headed towards the northeast practice area. At approximately 2;500 feet I noticed the engine was running extremely roughly. Suspecting the mixture was too rich I pulled the mixture back (less than 1 cm) the engine failed at that point. I re-added the mixture but noticed no change in power. I ran the engine out and troubleshoot checklists to no avail. I turned the aircraft towards ZZZ and contacted tower to let them know I was coming in. Tower [acknowledged the situation]; as I made a (fairly) straightforward approach and landing single engine. After landing the left engine was still running so I was able to taxi back to parking safely with no damage or injuries.

Original NASA ASRS Text

Title: PA-44 instructor pilot reported an engine failure led to a single engine approach and landing.

Narrative: I departed on a PA-44 training flight with a student. We did two laps in the pattern working on landings. After which we departed and headed towards the NE practice area. At approximately 2;500 feet I noticed the engine was running extremely roughly. Suspecting the mixture was too rich I pulled the mixture back (less than 1 cm) the engine failed at that point. I re-added the mixture but noticed no change in power. I ran the engine out and troubleshoot checklists to no avail. I turned the aircraft towards ZZZ and contacted Tower to let them know I was coming in. Tower [acknowledged the situation]; as I made a (fairly) straightforward approach and landing single engine. After landing the left engine was still running so I was able to taxi back to parking safely with no damage or injuries.

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.