Small Aircraft; High Wing; 1 Eng; Fixed Gear
Flight Crew Flight Instructor; Flight Crew Instrument
Flight Crew Last 90 Days 90; Flight Crew Total 439; Flight Crew Type 384
Distraction; Workload; Troubleshooting
Aircraft Equipment Problem Critical
Aircraft Aircraft Damaged; Flight Crew Returned To Departure Airport; Flight Crew Landed in Emergency Condition; Flight Crew Overcame Equipment Problem
Aircraft
Preflight; runup and take off were normal. At about 1;700 ft. I started smelling burnt rubber; I looked visually at the cowling and tires and saw nothing out of the ordinary. I then felt the entire panel with the back of my hand and felt no heat. Oil pressure and oil temp were in the green. Our climb rate was slower than normal but not completely abnormal for our particular plane. We leveled off at 2500 and noticed the rpm setting was at the bottom of the green arc with full throttle. Then felt a bang and heard clanking; we had lost partial power. I take controls and set my airspeed; look for a place to land (I knew there was an airport close to us) and tried to restart for full power to no avail. We figure out where the airport is exactly and plan for a [precautionary] landing there. Made our call and set up for a straight in on [Runway] XX at ZZZ. As we touched down; that's when we had complete engine failure. There were no injuries and both souls onboard were safe. There was oil all on the right side of the cowling; the piston and cylinder had been completely severed from each other and all the oil from the engine appeared to be out. I am not sure if anything could have been done to prevent this as we got no indications of anything abnormal on the ground; on the run up or on take off.
Shortly after exiting pattern area at 1;700 feet; there was simultaneously a smell of rubber and exhaust; with the rudder pedals vibrating. I notified the instructor that I felt something was wrong with the aircraft and was instructed to continue flying and just keep an eye out for a quick place to land or turn around; if needed; and to quickly assess the situation. I felt the need and suggested turning back to ZZZ. We were feeling the gauges for heat and looking for areas of possible smoke or exhaust; which we could smell. As we were assessing the situation; the rudder pedals started to shake more; with the plane as well vibrating roughly; and the smell got more intense. We leveled off at our cruising altitude of 2;500 AGL; destined for ZZZ1. Around this point; we noticed our engine RPM and climb rate was lacking significantly. The airplane was a slow climber as is; but the climb rate was a sluggish 300 fpm; compared to the normal 500 fpm. The engine RPM was 2500 rpm on takeoff; slowly moved down to 2300 during climb (with full throttle and full rich mixture); and was hovering around this area when we leveled off as well. Run-up was fine with good drops on magnetos and carb heat. No abnormal sounds during run-up. I asked the instructor to pull carb heat for me in case of carburetor icing. We kept it pulled for a matter of seconds; but noticed a significant RPM drop. Carb heat was then turned off; but the RPM continued to drop slowly to 2150 RPM; and slowly went outside the green arc steadily.I notified the instructor that the vertical speed indicator and airspeed indicator both were rapidly twitching up and down; giving erroneous and now obsolete readings indicating a pitot-static system malfunction. Approximately 25 seconds after noticing these instrument errors; the engine forcefully exploded with a small puff of dark grey/black smoke and a very quick burst of exhaust flame (which I believe was not an engine fire; but the combustion flame quickly exiting the cylinder that exploded). The entire engine block; cowling; and front of the aircraft was violently shaking; so much so that I thought it was going to fall off the aircraft. The entire front of the aircraft jolted about 3 to 5 inches upwards. After the explosion; there was an intense heat at my feet and legs (no injuries) that was bypassing the firewall of the aircraft. There was an instantaneous loss of power; with only about 1700RPM maximum output. Engine power was slowly decreasing and speed was decreasing from a 14 knot head wind and lack of engine power. I gave control the instructor via a positive three way exchange of commands after a quick realization of what event just took place. She flew the aircraft and landed while I navigated and communicated the situation over the radio. We made a mayday call and landed ZZZ2. After exiting the aircraft; we observed the oil had exploded and leaked all over the right side of the aircraft; down the right exhaust; nose gear; down the full length of the fuselage and empennage; and the horizontal stabilizers and its control surface. At this time we additionally observed damage to the cowling; screws; skin; and surrounding metal/paint. After removing the aircraft from the runway; I was informed over the phone that witnesses said that the aircraft was far louder than they've ever heard [type aircraft] before and sounded like a helicopter. I was told it sounded as if a cylinder was not working. With this information presented to the mechanic and pilots present to assist us after the [situation]; it was observed that the piston head of the cylinder violently exploded off; lodging itself into the side of the cowling; causing significant damage internally and externally. The entire front of the aircraft was nearly completely separated from the bottom half downward. Cracks; dents; and chipped paint and metal present on the entire front of the aircraft. The spinner and propeller hub were completely bent; angling upwards and pressing against the aircraft. As a whole; the piston head blew off explosively; exploding the oil inside the cowling and leaking out front; damaging the pitot-static system potentially; and damaging the aircraft significantly inside the cowling; the entire engine; and the front air frame. What I believe caused the problem is a cylinder rod came loose; detonation ring was not securely attached; or there was significant damage or wear on the cylinder that was overlooked at some point. The aircraft is very regularly at 100 hour inspections and is looked at by Maintenance regularly as part of the flight school and FAA regulations. We were told that the only reason there was still engine power was that the mixture was completely inoperative and only air was taken in; combusting with whatever residual fuel was in the cylinders. The propeller stopped as soon as the wheels touched the ground. Inside aircraft was very hot after the engine violently broke in flight. Alternator inoperative light came on after the piston head blew during flight and remained off until the master switch was turned off. Was informed by a CFI that heard my call that he could hear a 'tinking' sound over the radio and had an idea of what happened to our aircraft.We were informed by just about everyone that heard what happened that there was nothing more or less we could have done. The event that took place was not pilot error. We correctly aviated first; navigated second; and communicated last. Both the instructor and I came out with no injuries whatsoever. The aircraft landed safely; with all the necessary variables in our favor despite the dangerous circumstance. We both remained very calm and collected. With the very limited altitude available to us; we landed within 2 to 3 minutes. We both acted quickly with our training. Given the nature of the [situation]; the training that any pilot gets would never begin to encompass a situation of this nature for a small aircraft. The entire front of the plane looking like it's about to fall off; violent sounds; shaking; and quick loss of altitude and airspeed is not even close to how engine out training goes. We both executed the situation as well as we could have within human nature and flight training.
Flight Instructor and Student reported that while they were departing the traffic pattern; the engine malfunctioned followed by excessive vibration and partial loss of power.  They returned to the airport and experienced complete engine failure upon landing.