20260528006999I

On may 28, 2026, at approximately 2305Z, a Cessna 172S, received minor damage when it was involved in an incident while operating approximately 11 miles northwest of rochester NY near Brockport NY. There were no injuries to either the pilot or passenger. The aircraft was being operated as a title 14 CFR part 141 giving flight instructions. According to the flight instructor, the aircraft was given a preflight check plus engine runup and stated everything looked good. Flight instructor stated a normal rotation from kroc runway 28 and followed a vy climb out at 74 KIAS, followed by an on-course heading of 330 to the northwest practice area. He instructed the student to level off at 3500 indicated starting at 3400 using pitch, power, and trim with 2300 RPM. The student climbed to 3800 feet and at that time the instructor stated he smelled an odor like burning electrical equipment. The instructor verified the heat was off and asked the student if he smelled the odor, and the student also smelled the odor. The instructor stated he then took control of the aircraft and began returning to rochester airport, kroc. The instructor stated he called ATC and declared an emergency. At that time the instructor noticed external smoke near the cowlings but did not see any flames/fire. The instructor stated the engine started running rough and he knew it was not an electrical issue. The instructor stated he knew he was not going to make it back to kroc. The instructor stated he saw some fields below, and recalled winds out of the north. He stated he held his altitude with no change in power. The instructor loaded the nearest airport into the GPS and it showed 7G0. The instructor stated the engine was losing power and he heard a pop followed by oil spraying on the windshield, and the engine stopped. He stated he had to use the side windows to look out since oil covered the windshield. The instructor stated he used atc/foreflight/gps to find and align with runway 28 at 7G0. The instructor stated he was 5 miles from 7G0 initially, and he kept it high using best glide speed once he lost the engine. The instructor didn’t know when the propeller departed the aircraft. The instructor stated he was on a long final and was doing s turns to look outside and align the plane on final. He stated he landed on runway 28 with full flaps, after completing a forward slip on final to lose altitude and see out the side window. He stated the landing was surprisingly smooth when the aircraft stopped, he pulled the mixture, exited the plane with his student, and observed the cowling loose and hanging/sagging down. The aircraft was then moved into a hangar located on the airport (K7G0).

On may 29, 2026, at approximately 1030 am local time. This inspector arrived at the aircraft and verified that the propeller was not attached and had separated when the forward area of the engine crankshaft had fractured/broken in flight. The propeller was later found in the front lawn of a home in spencerport NY. No other damage to the aircraft structure or engine mounts was noted. Aircraft battery was disconnected. Oil filter housing removed with minor debris located on the magnetic pickup, with minor debris on filter element. The oil suction screen was removed, and numerous nonferrous metal debris were found. The bottom spark plugs were removed, and the engine was manually rotated at the accessory case where a vacuum pump would be installed. The engine was rotated and thumb compression was established on all cylinders.

06/16/2026 After Lycoming engines reviewed provided photos with one showing what is believed could be the origin point of the crankshaft failure. The crescent shaped markings that are emanating from what looks like a triangle now appears to be classic beach marks, which are indicative of a fatigue crack. The fatigue crack will grow and propagate until the surface area is reduced enough that the rest of the material fails in overload.