Skyhawk 172/Cutlass 172
Flight Crew Commercial; Flight Crew Flight Instructor; Flight Crew Instrument; Other UAS
Flight Crew Last 90 Days 140.4; Flight Crew Total 1051.9; Flight Crew Type 997
Troubleshooting
Aircraft Equipment Problem Critical
Air Traffic Control Provided Assistance; Flight Crew Overcame Equipment Problem; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Returned To Departure Airport; Flight Crew Landed As Precaution; General Flight Cancelled / Delayed; General Maintenance Action
Aircraft
I departed ZZZ with my PPL student for his second cross-country flight; destination ZZZ1. We departed runway XX with a downwind departure to the East. Climbing through 4;000 feet; I decided to get flight following due to low visibility in haze. I had just contacted [approach] and was halfway through my request when I noticed engine roughness. I immediately pitched for best glide speed; applied carb heat; and turned back toward ZZZ with just enough engine power to maintain altitude. The carb heat had no effect. I informed approach of my situation; and they were able to locate me without a unique squawk code. The controller told me the location of the airport (though I already had it in sight) and asked me to call them when we were safely on the ground. I was able to maintain an altitude of 4;000 feet and navigated directly over ZZZ. I made a call on the CTAF informing all traffic that I had engine problems; and asked them to yield. An aircraft on approach to runway XY broke off and exited the pattern. Winds were light; so I chose to spiral down over the numbers for XX and join the right downwind. I was able to land without incident; and taxi back to the FBO where I noticed that oil was leaking down the nose gear strut. Upon inspection by the mechanic on site; I had thrown a rod in the number 3 cylinder. Oil temperature and pressure were both normal for the duration of the flight. The cylinder was replaced and the aircraft has been returned to service.
Instructor Pilot reported an air turn back caused by engine problems.