Rough running engine causes pilot to make an emergency landing.

Attributes
ACN	154637
Time
Date	199008
Day	Sat
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : mfr
State Reference	OR
Altitude	agl bound lower : 0 agl bound upper : 1300
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : mfr tower : dvt
Operator	general aviation : personal
Make Model Name	Small Aircraft, Low Wing, 1 Eng, Fixed Gear
Flight Phase	descent : approach landing : missed approach landing other
Flight Plan	None
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : private
Experience	flight time last 90 days : 43 flight time total : 377 flight time type : 377
ASRS Report	154637
Person 2
Affiliation	government : faa
Function	controller : local
Qualification	controller : non radar
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	other flight crewa
Resolutory Action	flight crew : declared emergency other
Consequence	Other
Supplementary
Primary Problem	Aircraft

Narrative:

Upon climbing out of a missed approach for a VOR-a, the magnetos started to misfire causing the engine to act rough. I then declared an emergency with the tower and and was cleared to land on runway 32. When asked the cause, I told them the engine was rough and acting abnormally. Upon landing the spark plugs were checked and appeared to be fouled with lead. They were then cleared.

Original NASA ASRS Text

Title: ROUGH RUNNING ENGINE CAUSES PLT TO MAKE AN EMERGENCY LNDG.

Narrative: UPON CLBING OUT OF A MISSED APCH FOR A VOR-A, THE MAGNETOS STARTED TO MISFIRE CAUSING THE ENG TO ACT ROUGH. I THEN DECLARED AN EMER WITH THE TWR AND AND WAS CLRED TO LAND ON RWY 32. WHEN ASKED THE CAUSE, I TOLD THEM THE ENG WAS ROUGH AND ACTING ABNORMALLY. UPON LNDG THE SPARK PLUGS WERE CHKED AND APPEARED TO BE FOULED WITH LEAD. THEY WERE THEN CLRED.

Data retrieved from NASA's ASRS site as of July 2007 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.