CHI97LA091

The CFI reported that after takeoff at an altitude of about 300 feet above the ground the airplane started to '...vibrate severely, followed almost immediately by a loud bang in the engine compartment.' The CFI made a left turn to return to the airport and was cleared to land. He reported hearing another loud bang at which time the forward left portion of the cowling distorted. A forced landing was made in a field during which the nose gear collapsed and the airplane nosed over. Postaccident inspection and metallurgical examination revealed the number 2 cylinder separated between the mounting flange and the head due to fatigue.

On March 26, 1997, at 1426 central standard time, a Cessna 152, N6359M operated by the Ft. Leavenworth Flying Club nosed over during a forced landing at the Sherman Army Airfield, Ft. Leavenworth, Kansas. The certified flight instructor reported a loss of engine power during the initial takeoff climb from runway 15. Neither the certified flight instructor (CFI) nor the student pilot on board were injured. The airplane was substantially damaged. The local 14 CFR Part 91 flight was operating in visual meteorological conditions without a flight plan.

The CFI reported that engine operated normally during the engine run-up. He reported they departed on runway 15 and were cleared to make a right turn after takeoff. The CFI reported that since there was a strong crosswind he performed the takeoff. He reported that during the takeoff climb at an altitude of about 300 feet above ground level (agl) he lowered the nose to increase airspeed. It was at this time that the "... airplane started to vibrate severely, followed almost immediately by a loud bang in the engine compartment." He reported that he made an immediate left turn and informed the air traffic control tower that they were having engine problems. The CFI continued to report, "While the tower was clearing us to land, there was another loud bang from the engine compartment, more loud and intense than the one before. At the same time as the bang occurred, the forward left portion on the cowling distorted out and up, pushing out the zeus bolts. The prop then stopped in the vertical position."

The CFI reported that he performed the forced landing checklist and chose a field in which to land. He reported that during the landing he was unable to keep the nose gear off the ground. The nose gear collapsed as it touched down and the airplane nosed over. The CFI and student exited the airplane without injury.

The engine from N6359M, a Lycoming O-235-LC2, s/n RL-25322-15, was removed from the airplane after the accident and shipped to Textron-Lycoming, Williamsport, Pennsylvania, for a teardown under the supervision of a Federal Aviation Administration Inspector from the Harrisburg Flight Standards District Office. Upon inspection of the engine it was determined that a portion of the number 2 cylinder had separated from the crankcase. The number 2 cylinder and its related components were then shipped the NTSB Materials Laboratory in Washington, D.C. for further inspection.

Metallurgical examination revealed "...faint beachmarks..." which are "...consistent with a fatigue crack that began at the outer diameter of the barrel and progressed inward toward the inside surface and circumferentially around the barrel." See attached Metallurgist's Factual Report for further details.