PA-44 Flight Instructor and student reported a partial power approach with subsequent engine failure upon landing. Airplane exited the runway and was towed to ramp.
Synopsis
PA-44 Flight Instructor and student reported a partial power approach with subsequent engine failure upon landing. Airplane exited the runway and was towed to ramp.
Narrative
While conducting a Multi Engine End of Course; we experienced a failure of the left engine in flight. The plane was noted to have struggled starting the right engine earlier in the day by a different instructor. When we entered the plane we were able to start both engines with no issues. We conducted a full run up where nothing abnormal was noted. On takeoff we conducted a simulated failure of the right engine on the takeoff roll using the throttle. We again conducted a simulated failure of the right engine in the climb out at roughly 1000 AGL again using the throttle. Upon reaching altitude; we conducted a full shutdown and secure of the right engine where the failure was simulated by turning the fuel selector off. After the engine was secured; we performed an air start of the right engine. Nothing abnormal was noted during any phase of flight up to this point. After waiting for the right engine to regain normal operating temperatures; I asked the student to set up into slow flight. After completing clearing turns; the student brought both throttles back to begin slowing the plane down and noted to me 'something doesn't feel right'. I noted that both while both engines were roughly indicating 21' of manifold pressure; the left engine was indicating 1600 RPM; significantly lower than the right engine. At this point; I took controls from the student and ran the basic troubleshooting checklist; making sure both mixtures were full; both prop levers were full forward; both throttles were full; brought the flaps and the gear up; and ensured that all magnetos were switched to on; both fuel selectors were switched to on; and both auxiliary fuel pumps were turned on. While troubleshooting and running the checklist; I noted that the CHT on the left engine had dropped out of the green arc despite having been operating normally to that point; and observed a noticeably lower EGT indication on cylinder two. From there; I realized that if I kept the left throttle setting above approximately 18' of manifold pressure; the engine was still producing power and giving normal indications. Below that power setting; no power was observed and the EGT indications across the board would bottom out. I elected to not secure the problem engine as we were still able to produce power. I descended to enter the left downwind for Runway XX at ZZZ and flew a relatively normal pattern with a slightly higher power setting and electing to not use full flaps. After turning final and descending through roughly 500 AGL; I reduced both throttle settings in order to begin slowing the plane to a reasonable approach speed. At this point; I noticed the left engine not making any power any more and continued to make the landing. Upon rolling out on landing I noticed the left propeller stop windmilling and come to a stop. At this point Tower notified us that they observed a puff of smoke coming from the left engine on final; and the student elected to turn off the magnetos; fuel pump; fuel selector; and cut off the mixture for the left engine. We were able to clear the runway under our own power; where we were met by the fire department. We fully shutdown the aircraft upon exiting the runway and were towed back to the company ramp by maintenance personnel.
Second reporter narrative
Everything was normal through start up and climbout. We performed an engine out at altitude by shutting down the right engine using the fuel selector; then we ran through the checklists and restarted the right engine without a problem. After completing a 180 clearing turn to the west; I began to slow the aircraft down and configure for slow flight. I lowered the gear and put in the first notch of flaps; but then I felt myself beginning to lose directional control; so I counteracted with rudder and got us stabilized on course. I knew at that point something was wrong with the left engine; and rechecked the fuel selector to make sure it was on. It was. At that point I said to the instructor; 'something doesn't feel right.' So the instructor took controls and we started to check everything. As we watched the engine indications; we observed the manifold pressure of the left engine to be about 21' but the RPM was falling and had gotten around 1600. The instructor continued to fly and I assisted with checklists. We noticed that it appeared to be a partial power loss; so the instructor was able to get the engine working at a higher manifold pressure. He turned us to the north back towards ZZZ at which point we contacted ZZZ Tower and told them we were inbound and had a partial power loss; but it was not yet an emergency. With the Tower's instruction; we continued inbound for Runway XX and went through the before landing checks. As we neared the runway on final; the instructor pulled the power out slightly to help slow down; at which point the left engine completely died. The Tower alerted us that black smoke had shot out of the engine for a few seconds; but had stopped. The instructor successfully landed on a single engine and then he taxied the plane off the runway onto [Taxiway] 1 while I secured the left engine; making sure all the fuel was cut off in case of a fire. We came to a stop and Tower asked us to shut down the remaining right engine so that the firemen could move in to inspect the plane.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.