Rough engine. Declares emergency and lands nearest airport.

Attributes
ACN	162603
Time
Date	199011
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : m08
State Reference	TN
Altitude	msl bound lower : 4000 msl bound upper : 4000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	general aviation : personal
Make Model Name	Small Aircraft, Low Wing, 1 Eng, Fixed Gear
Flight Phase	cruise other
Route In Use	enroute airway : zme
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : private pilot : instrument
Experience	flight time last 90 days : 75 flight time total : 555 flight time type : 50
ASRS Report	162603
Person 2
Affiliation	government : faa
Function	controller : radar
Qualification	controller : 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:

Between approximately xa:30 and xa:45 local time while cruising at 4000' MSL there was an abrupt partial loss in the engine power. While trying to determine the cause of the power loss approximately 300-4--' of altitude was lost. During this time it was determined that there was an emergency. After calling ZME I was advised of the distance and location of the bolivar airport. I advised center I was proceeding direct and that I had an engine problem and I was then cleared for a visibility approach. A determination was later made by an a & P mechanic that the #6 exhaust valve had broken causing that cylinder not to produce power. After this finding I feel I used my authority/authorized as PIC safely in order to protect the safety and well being of myself and my passengers.

Original NASA ASRS Text

Title: ROUGH ENGINE. DECLARES EMERGENCY AND LANDS NEAREST ARPT.

Narrative: BTWN APPROX XA:30 AND XA:45 LCL TIME WHILE CRUISING AT 4000' MSL THERE WAS AN ABRUPT PARTIAL LOSS IN THE ENG PWR. WHILE TRYING TO DETERMINE THE CAUSE OF THE PWR LOSS APPROX 300-4--' OF ALT WAS LOST. DURING THIS TIME IT WAS DETERMINED THAT THERE WAS AN EMER. AFTER CALLING ZME I WAS ADVISED OF THE DISTANCE AND LOCATION OF THE BOLIVAR ARPT. I ADVISED CTR I WAS PROCEEDING DIRECT AND THAT I HAD AN ENG PROB AND I WAS THEN CLRED FOR A VIS APCH. A DETERMINATION WAS LATER MADE BY AN A & P MECH THAT THE #6 EXHAUST VALVE HAD BROKEN CAUSING THAT CYLINDER NOT TO PRODUCE PWR. AFTER THIS FINDING I FEEL I USED MY AUTH AS PIC SAFELY IN ORDER TO PROTECT THE SAFETY AND WELL BEING OF MYSELF AND MY PAXS.

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.