Cardinal 177/177RG
Flight Crew Instrument; Flight Crew Private; Flight Crew Sea
Flight Crew Last 90 Days 11; Flight Crew Total 2227; Flight Crew Type 1500
Communication Breakdown; Situational Awareness
Aircraft Equipment Problem Critical; Deviation - Altitude Excursion From Assigned Altitude; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance
Air Traffic Control Provided Assistance; Flight Crew Diverted; Flight Crew Landed in Emergency Condition; Flight Crew Requested ATC Assistance / Clarification
Aircraft; Human Factors
I was enroute on an IFR flight plan at 12;000 feet. Center had cleared me direct [VOR]; then as filed. I noticed the JPI engine monitor; which previously had shown normal engine temperatures on all cylinders; was indicating an alarm condition for high CHT's on the Number 2 cylinder. Concerned about an engine failure in instrument conditions; I immediately reduced power and began to search for the nearest airport with an instrument approach using my GPS. Center then called; asking for my altitude. I explained the situation and requested information as to the nearest suitable airport. Center replied that ZZZ was nearby and gave me a heading; and a clearance to descend and maintain 7;000 feet; if possible. I turned toward the airport and continued my descent. As I descended; the aircraft emerged from the clouds and I saw the airport at 12 o'clock. At that point I cancelled IFR; continued the descent and landed without incident. The problem was that I did not remain on my cleared heading and altitude due to the fact that I prioritized maintaining whatever engine power I might have left for a precautionary landing. I should have contacted Center as soon as I felt that a diversion was necessary; and informed them of the situation more promptly than I did.
C177 pilot on an IFR flight plan at 12;000 feet notes high CHT and begins reducing power and descending without communicating with Center. ATC notes the descent then provides assistance when the descent is explained. An uneventful landing ensues.