C172 Flight Instructor and student reported the engine began running rough and vibrating violently during takeoff roll. Flight crew rejected takeoff; returned to the ramp; and advised maintenance personnel.
Synopsis
C172 Flight Instructor and student reported the engine began running rough and vibrating violently during takeoff roll. Flight crew rejected takeoff; returned to the ramp; and advised maintenance personnel.
Narrative
Experienced engine roughness during the takeoff roll. First experienced the issue while taxiing onto the runway. I slightly enriched the mixture and it felt as if the engine was running normal. Once on the runway; my student started applying full power and the engine was not producing power and was running rough. I adjusted the mixture knob inside the aircraft once again to see if it was a performance issue. Adjustments did not work no date engine was not producing enough power to initiate rotation. My student informed tower we were aborting takeoff. Able to taxi off the runway without problem. Went into the ramp area to further diagnose the issue. While running up the engine; we experienced the same rough running engine. Checked the magnetos; and magnetos checked off as normal. Oil temperature and pressure were normal; and we had full fuel. I believe the engine may have a cylinder problem. My student and I both agreed to cancel our flight due to the rough running engine and to remain safe. I informed our maintenance department of the problem. Before takeoff; all indications of the engine were normal. Our run up went normal and we saw no issues. We had to wait about 20 minutes before we ahead clearance from tower for takeoff. During this idle time the engine could have been experiencing issues; but at the low RPM we could not detect anything. Both my student and I worked together well during this situation to quickly determine that we could not continue with our takeoff due to the lack of engine performance.
Second reporter narrative
While waiting for my takeoff clearance; my flight instructor and I notice the engine begin to vibrate and he enriched the engine and the vibration went away. A few minutes later; we received our takeoff clearance and I gave the engine full power on the center line. The engine begin to violently vibrate. I checked the magnetos they were on both. The power was not enough to take off; we had to abort and contacted ATC to inform them about our situation. We taxied off the runway back to the ramp area; my instructor increased the power and to make sure the loss of engine RPM was good. The engine loss of power and vibration continued. We informed maintenance about the situation.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.