Narrative:

While on a normal flight instruction flight; demonstrating and practicing power-off stalls with a private pilot student; the student was recovering from the third power-off stall. She lowered the nose and tried to apply full power. However; the throttle would not move from the low position. I; as the flight instructor; took the flight controls and tried to dislodge the throttle; however; it would not move -- it felt as if the throttle linkage was binding. I noticed that the RPM was stable at 1000 RPM; slightly above idle; providing me with minimal power. I acted towards the situation as if it were a complete engine failure; pitched for best glide speed and chose a field to land on approximately 1 mi east of our position. After entering a high downwind for the field; I contacted tower; declared an emergency; and squawked 7700. Tower gave a wind readout and stated they had our aircraft on radar. The field was approximately 1 mi in length and width with minimal vegetation; however; it was outlined with power lines. Coming over the power lines; and once past them; I pulled out the mixture to eliminate any thrust from the slightly higher than idle power setting and dropped flaps to 40 degrees. Using a soft field technique; I was successfully able to land the aircraft with no harm to either my student or I; as well as no damage to the aircraft. I then called tower on the phone to inform them of our safe landing. Following this; I called the company chief instructor who then came with 2 company mechanics. After an inspection of the throttle cable the mechanics determined that the cable needed to be replaced; however; they would be able to position the cable for the flight back to ZZZ so that it would be safe for flight. After calculating the weight and balance; takeoff performance; determining my course of action should another throttle problem occur during my departure; and arranging a ride for my student; I as the sole occupant of the aircraft; performed a soft field takeoff into the wind out of the field. The flight back to ZZZ lasted 0.3 hours and was uneventful. I then landed safely at ZZZ where the aircraft is being tended to further.

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Original NASA ASRS Text

Title: FLT INSTRUCTOR AND STUDENT EXPERIENCE THROTTLE STUCK AT IDLE WHILE PRACTICING STALLS.

Narrative: WHILE ON A NORMAL FLT INSTRUCTION FLT; DEMONSTRATING AND PRACTICING PWR-OFF STALLS WITH A PVT PLT STUDENT; THE STUDENT WAS RECOVERING FROM THE THIRD PWR-OFF STALL. SHE LOWERED THE NOSE AND TRIED TO APPLY FULL PWR. HOWEVER; THE THROTTLE WOULD NOT MOVE FROM THE LOW POS. I; AS THE FLT INSTRUCTOR; TOOK THE FLT CTLS AND TRIED TO DISLODGE THE THROTTLE; HOWEVER; IT WOULD NOT MOVE -- IT FELT AS IF THE THROTTLE LINKAGE WAS BINDING. I NOTICED THAT THE RPM WAS STABLE AT 1000 RPM; SLIGHTLY ABOVE IDLE; PROVIDING ME WITH MINIMAL PWR. I ACTED TOWARDS THE SITUATION AS IF IT WERE A COMPLETE ENG FAILURE; PITCHED FOR BEST GLIDE SPD AND CHOSE A FIELD TO LAND ON APPROX 1 MI E OF OUR POS. AFTER ENTERING A HIGH DOWNWIND FOR THE FIELD; I CONTACTED TWR; DECLARED AN EMER; AND SQUAWKED 7700. TWR GAVE A WIND READOUT AND STATED THEY HAD OUR ACFT ON RADAR. THE FIELD WAS APPROX 1 MI IN LENGTH AND WIDTH WITH MINIMAL VEGETATION; HOWEVER; IT WAS OUTLINED WITH PWR LINES. COMING OVER THE PWR LINES; AND ONCE PAST THEM; I PULLED OUT THE MIXTURE TO ELIMINATE ANY THRUST FROM THE SLIGHTLY HIGHER THAN IDLE PWR SETTING AND DROPPED FLAPS TO 40 DEGS. USING A SOFT FIELD TECHNIQUE; I WAS SUCCESSFULLY ABLE TO LAND THE ACFT WITH NO HARM TO EITHER MY STUDENT OR I; AS WELL AS NO DAMAGE TO THE ACFT. I THEN CALLED TWR ON THE PHONE TO INFORM THEM OF OUR SAFE LNDG. FOLLOWING THIS; I CALLED THE COMPANY CHIEF INSTRUCTOR WHO THEN CAME WITH 2 COMPANY MECHS. AFTER AN INSPECTION OF THE THROTTLE CABLE THE MECHS DETERMINED THAT THE CABLE NEEDED TO BE REPLACED; HOWEVER; THEY WOULD BE ABLE TO POS THE CABLE FOR THE FLT BACK TO ZZZ SO THAT IT WOULD BE SAFE FOR FLT. AFTER CALCULATING THE WT AND BAL; TKOF PERFORMANCE; DETERMINING MY COURSE OF ACTION SHOULD ANOTHER THROTTLE PROB OCCUR DURING MY DEP; AND ARRANGING A RIDE FOR MY STUDENT; I AS THE SOLE OCCUPANT OF THE ACFT; PERFORMED A SOFT FIELD TKOF INTO THE WIND OUT OF THE FIELD. THE FLT BACK TO ZZZ LASTED 0.3 HRS AND WAS UNEVENTFUL. I THEN LANDED SAFELY AT ZZZ WHERE THE ACFT IS BEING TENDED TO FURTHER.

Data retrieved from NASA's ASRS site as of May 2009 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.