C172 pilot reported a severe vibration from the engine and a loss of power event. A landing was made...

Narrative:

Preflight was thorough and there were no indications of problem areas other than some wrinkled skin on the horizontal stabilizer which was common for this [older] aircraft. No previous indications were present when suddenly a violent vibration occurred coming from the engine compartment associated with a loss of thrust. I immediately began a turning left hand climb 180 degrees to return to the departure airport. At the time the throttle was at 2200 RPM; 110 knots; and mixture leaned 2 full turns; carb heat off. I climbed to 3800 feet in the turn directly over the VORTAC direct to the departure airport. Upon reaching 3800 feet under full throttle and full rich mixture; the aircraft was at 70 knots and no longer able to continue climbing and under full power descended at 70 knots to 2200 feet before I was able to keep the altitude steady. Speaking with approach it was determined an alternate airport was directly in my path and the best choice for a landing. I was able to keep the aircraft at 2200 feet till closer to the field; brought the throttle to idle and landed without further incident. However during the cruise phase to 2200 the aircraft still was vibrating violently; once the throttle was back at idle the vibrations dampened significantly. Upon landing and taxi to the FBO the vibration was still present somewhat and a chugging sound could be heard. No further information is available at this time as maintenance personnel have not yet looked at the aircraft.

Original NASA ASRS Text

Title: C172 pilot reported a severe vibration from the engine and a loss of power event. A landing was made at a nearby airport. Maintenance inspection revealed a failed piston and connecting rod on the Number 3 cylinder caused the issue.

Narrative: Preflight was thorough and there were no indications of problem areas other than some wrinkled skin on the horizontal stabilizer which was common for this [older] aircraft. No previous indications were present when suddenly a violent vibration occurred coming from the engine compartment associated with a loss of thrust. I immediately began a turning left hand climb 180 degrees to return to the departure airport. At the time the throttle was at 2200 RPM; 110 knots; and mixture leaned 2 full turns; carb heat off. I climbed to 3800 feet in the turn directly over the VORTAC direct to the departure airport. Upon reaching 3800 feet under full throttle and full rich mixture; the aircraft was at 70 knots and no longer able to continue climbing and under full power descended at 70 knots to 2200 feet before I was able to keep the altitude steady. Speaking with Approach it was determined an alternate airport was directly in my path and the best choice for a landing. I was able to keep the aircraft at 2200 feet till closer to the field; brought the throttle to idle and landed without further incident. However during the cruise phase to 2200 the aircraft still was vibrating violently; once the throttle was back at idle the vibrations dampened significantly. Upon landing and taxi to the FBO the vibration was still present somewhat and a chugging sound could be heard. No further information is available at this time as Maintenance personnel have not yet looked at the aircraft.

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.

Attributes
ACN	1378191
Time
Date	201608
Local Time Of Day	1801-2400
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Aircraft 1
Make Model Name	Skyhawk 172/Cutlass 172
Operating Under FAR Part	Part 91
Flight Phase	Cruise
Route In Use	Direct
Flight Plan	VFR
Component
Aircraft Component	Engine
Person 1
Function	Pilot Flying Single Pilot
Qualification	Flight Crew Instrument Flight Crew Multiengine Flight Crew Commercial
Experience	Flight Crew Last 90 Days 90 Flight Crew Total 493 Flight Crew Type 77
Events
Anomaly	Aircraft Equipment Problem Critical

C172 pilot reported a severe vibration from the engine and a loss of power event. A landing was made at a nearby airport. Maintenance inspection revealed a failed piston and connecting rod on the number 3 cylinder caused the issue.