Continental; TSIO 520R; Failed Exhaust Valve; ATA 8530

It was close to noon and 17,000 feet over Pueblo, Colorado, when this pilot experienced a loud backfire, severe vibration, and a loss of engine power. The Cessna T210 was IFR to Denton, Texas. “I immediately reduced power and the vibration stopped,” writes the pilot. “I declared an emergency with Center and asked for the nearest suitable airport which had good weather. Colorado Springs, which was VFR, was offered and accepted.” He reported having sufficient power to assist in a controlled descent to the airport where a safe landing was made.

Maintenance found approximately forty percent of an exhaust valve head (P/N 637781) had given away, severely damaging cylinder number one. The broken valve piece was found in the intake tube, having previously contacted both the piston and cylinder head surfaces. No speculation as to cause of the valve’s failure was provided.

Part Total Time: (unknown).