Narrative:

Skyhawk had a massive power loss that resulted in an emergency landing. I was flying with my student. We were practicing maneuvers in an area known as the beach practice area. We were under approach radar with a squawk code for advisories. We were working a simulated emergency landing in which he needed to run the procedure per the checklist. We decided to abandon the maneuver after we noticed an aircraft flying within the vicinity of us. I instructed my student to turn southbound and fly towards the beachline as we were in the middle of the waterway. We had lost sight of the traffic flying towards us. I instructed my student to climb so we could avert trouble. As soon as he advanced the throttles forward for the climb; there was a sudden bang and violent vibration coming from the engine compartment. I immediately took control of the airplane and tried to assess the situation. The engine normally produces its maximum power at an RPM greater than 2500 RPM. At the moment we were only producing 2100 RPM and it was steadily decreasing. I ran the emergency engine failure checklist. We developed a sink rate of 200 feet per minute while trying maintain altitude. We were at an altitude of 1500 and sinking. I contacted approach; and let them know that we would be making an emergency landing at the nearest landing field. A small field was the only place of landing that I could assure would not have resulted in bodily injury or loss of life. I was able to make a safe landing without incident. Police came to the scene and took a statement. The aircraft owner determined that the cause of the power loss was because the number 3 cylinder cracked in flight and was self-destructing.

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Original NASA ASRS Text

Title: A C172 cylinder cracked while on a training flight at 2;500 feet; so the Instructor assumed the controls and safely diverted to a nearby field.

Narrative: Skyhawk had a massive power loss that resulted in an emergency landing. I was flying with my student. We were practicing maneuvers in an area known as the beach practice area. We were under approach radar with a squawk code for advisories. We were working a simulated emergency landing in which he needed to run the procedure per the checklist. We decided to abandon the maneuver after we noticed an aircraft flying within the vicinity of us. I instructed my student to turn southbound and fly towards the beachline as we were in the middle of the waterway. We had lost sight of the traffic flying towards us. I instructed my student to climb so we could avert trouble. As soon as he advanced the throttles forward for the climb; there was a sudden bang and violent vibration coming from the engine compartment. I immediately took control of the airplane and tried to assess the situation. The engine normally produces its maximum power at an RPM greater than 2500 RPM. At the moment we were only producing 2100 RPM and it was steadily decreasing. I ran the emergency engine failure checklist. We developed a sink rate of 200 feet per minute while trying maintain altitude. We were at an altitude of 1500 and sinking. I contacted Approach; and let them know that we would be making an emergency landing at the nearest landing field. A small field was the only place of landing that I could assure would not have resulted in bodily injury or loss of life. I was able to make a safe landing without incident. Police came to the scene and took a statement. The aircraft owner determined that the cause of the power loss was because the number 3 cylinder cracked in flight and was self-destructing.

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.