The pilot of a cessna 402 experienced a rough running engine in cruise flight. After cycling the mag...

Attributes
ACN	1142221
Time
Date	201401
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.TRACON
State Reference	US
Environment
Flight Conditions	VMC
Light	Dawn
Aircraft 1
Make Model Name	Cessna 402/402C/B379 Businessliner/Utiliner
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Component
Aircraft Component	Magneto/Distributor
Person 1
Function	Captain Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Aircraft Equipment Problem Critical

Narrative:

After I leveled off at 9;000 ft; the engines started running rough. There was knocking and rocking of the airplane. The right cht [indication] was significantly lower than the [left] one. I cycled the mags; when I got to the right engine left mag off; the right engine nearly quit. I returned back to [the departure airport] without any problems. I did not declare an emergency and [ATC] gave me radar vectors around to final [approach].

Original NASA ASRS Text

Title: The pilot of a Cessna 402 experienced a rough running engine in cruise flight. After cycling the magneto switch; he observed that the right engine had a malfunctioning right magneto; so he elected to return to the departure airport where a successful landing was performed.

Narrative: After I leveled off at 9;000 FT; the engines started running rough. There was knocking and rocking of the airplane. The right CHT [indication] was significantly lower than the [left] one. I cycled the mags; when I got to the right engine left mag off; the right engine nearly quit. I returned back to [the departure airport] without any problems. I did not declare an emergency and [ATC] gave me radar vectors around to final [approach].

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.

The pilot of a cessna 402 experienced a rough running engine in cruise flight. After cycling the magneto switch; he observed that the right engine had a malfunctioning right magneto; so he elected to return to the departure airport where a successful landing was performed.