C185 pilot reported an engine failure during governor testing led to a return to the departure airpo...

Attributes
ACN	1594000
Time
Date	201811
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Skywagon 185
Operating Under FAR Part	Part 91
Flight Phase	Descent
Flight Plan	None
Component
Aircraft Component	Engine
Person 1
Function	Single Pilot
Qualification	Flight Crew Instrument Flight Crew Air Transport Pilot (ATP) Flight Crew Flight Instructor Flight Crew Multiengine
Experience	Flight Crew Total 6800 Flight Crew Type 8
Events
Anomaly	Aircraft Equipment Problem Critical Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor

Narrative:

While conducting some propeller and governor testing in a cessna 185 with an experimental airworthiness certificate; I experienced a catastrophic engine failure while descending through approximately 6000 feet. The #2 cylinder connecting rod failed which punched a hole in the top of the engine case. Oil covered the windshield and smoke filled the cockpit. The engine continued to run on 5 cylinders and the right magneto under reduced power. I was able to get the airplane back to the airport and land safely. The failure happened approximately 5 miles from the airport.

Original NASA ASRS Text

Title: C185 pilot reported an engine failure during governor testing led to a return to the departure airport.

Narrative: While conducting some propeller and governor testing in a Cessna 185 with an experimental airworthiness certificate; I experienced a catastrophic engine failure while descending through approximately 6000 feet. The #2 cylinder connecting rod failed which punched a hole in the top of the engine case. Oil covered the windshield and smoke filled the cockpit. The engine continued to run on 5 cylinders and the right magneto under reduced power. I was able to get the airplane back to the airport and land safely. The failure happened approximately 5 miles from the airport.

Data retrieved from NASA's ASRS site 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.