Narrative:

We departed ZZZ airport to the southwest practice area to do a review flight with my student. We were passing over military airspace heading to [a local] lake. After passing [the] lake we started performing slow flight (3500 feet; 240 heading). Then; I asked the student to perform the maneuver (about 3300 feet; 210 heading) and upon recovery the student added full power and then started to remove the flaps. After removing the first notch; the engine started knocking 'severe engine roughness.' after that I took control to recover. Moments after; we had smoke in the cockpit. We were around 2800 feet so I reported to ZZZ tower our aircraft call sign and position. Then maintained glide speed 73 KTS. Picked out a field and started heading towards the field. After losing altitude we reported again to ZZZ tower that we are making an emergency landing in a field 3 to 4 nautical miles south of [the] lake; that we have smoke in the cockpit; and engine failure with two people on board. Then they asked us if we had fuel; I replied; 'almost full fuel.' then started doing engine restart procedures. While doing this the tower tried to direct us to ZZZ; then they got confused and thought we [were] 'northwest of ZZZ airport.' they tried to give us heading to ZZZ1 'northwest of our position.' we were around 1400 MSL. Tower asked us to make a 180 degree turn if possible go to ZZZ1. So I declined the request and continued gliding towards the field; did securing procedures and concentrated on making a safe landing. Squawked 7700 and kept going to the field. Made a safe 'soft field landing' and evacuated the aircraft. Aircraft was not damaged at all.

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Original NASA ASRS Text

Title: A PA28 flight instructor reported an off-field emergency landing due to an engine failure and smoke in the cabin.

Narrative: We departed ZZZ airport to the southwest practice area to do a review flight with my student. We were passing over military airspace heading to [a local] lake. After passing [the] lake we started performing slow flight (3500 feet; 240 heading). Then; I asked the student to perform the maneuver (about 3300 feet; 210 heading) and upon recovery the student added full power and then started to remove the flaps. After removing the first notch; the engine started knocking 'severe engine roughness.' After that I took control to recover. Moments after; we had smoke in the cockpit. We were around 2800 feet so I reported to ZZZ Tower our aircraft call sign and position. Then maintained glide speed 73 KTS. Picked out a field and started heading towards the field. After losing altitude we reported again to ZZZ Tower that we are making an emergency landing in a field 3 to 4 nautical miles south of [the] lake; that we have smoke in the cockpit; and engine failure with two people on board. Then they asked us if we had fuel; I replied; 'almost full fuel.' Then started doing engine restart procedures. While doing this the tower tried to direct us to ZZZ; then they got confused and thought we [were] 'northwest of ZZZ Airport.' They tried to give us heading to ZZZ1 'northwest of our position.' We were around 1400 MSL. Tower asked us to make a 180 degree turn if possible go to ZZZ1. So I declined the request and continued gliding towards the field; did securing procedures and concentrated on making a safe landing. Squawked 7700 and kept going to the field. Made a safe 'soft field landing' and evacuated the aircraft. Aircraft was not damaged at all.

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.