C177 pilot on an IFR flight plan at 12;000 feet notes high cht and begins reducing power and descend...

Attributes
ACN	1077814
Time
Date	201304
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Make Model Name	Cardinal 177/177RG
Operating Under FAR Part	Part 91
Flight Phase	Cruise
Route In Use	Direct
Flight Plan	IFR
Component
Aircraft Component	Reciprocating Engine Assembly
Person 1
Function	Pilot Flying Single Pilot
Qualification	Flight Crew Instrument Flight Crew Private Flight Crew Sea
Experience	Flight Crew Last 90 Days 11 Flight Crew Total 2227 Flight Crew Type 1500
Events
Anomaly	Aircraft Equipment Problem Critical Deviation - Altitude Excursion From Assigned Altitude Deviation - Procedural Clearance Deviation - Track / Heading All Types

Narrative:

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.

Original NASA ASRS Text

Title: 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.

Narrative: 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.

Data retrieved from NASA's ASRS site as of July 2013 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

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.