GA small aircraft partial engine failure. Emergency landing at nearby airport.

Attributes
ACN	90993
Time
Date	198807
Day	Wed
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : sgf
State Reference	MO
Altitude	msl bound lower : 7500 msl bound upper : 7500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : sgf tower : sgf artcc : zob
Operator	general aviation : personal
Make Model Name	Small Aircraft, Low Wing, 1 Eng, Fixed Gear
Flight Phase	cruise other
Flight Plan	None
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : private
Experience	flight time last 90 days : 20 flight time total : 220 flight time type : 120
ASRS Report	90933
Person 2
Affiliation	government : faa
Function	controller : local
Qualification	controller : non radar
Events
Anomaly	aircraft equipment problem : critical other anomaly other
Independent Detector	other flight crewa
Resolutory Action	flight crew : declared emergency none taken : unable other
Consequence	Other
Supplementary
Primary Problem	Aircraft

Narrative:

We departed dallas north airport at XA30 on 7/wed/88 with 52 gals of 100 ll fuel (6.5 hours) for the 4.5 hour flight to stl. Cruise altitude was 7500' MSL. Three hours after takeoff the engine began running extremely rough. I declared an emergency by calling the sgf tower. Tower had me contact sgf approach. I was assigned a transponder code and given clearance for a straight in approach to runway 19. We landed safely at sgf. No one was injured and no damage was sustained to the aircraft. Inspection of the engine revealed metal fragments in all 4 cylinders and the oil screen. The mechanic believes that an intake valve failed. The engine must be replaced. From talking with other mechanics, I feel that this type of engine failure could have been prevented if the mechanic who performed my annuals had questioned the low compression on the #4 cylinder.

Original NASA ASRS Text

Title: GA SMA PARTIAL ENGINE FAILURE. EMERGENCY LNDG AT NEARBY ARPT.

Narrative: WE DEPARTED DALLAS NORTH ARPT AT XA30 ON 7/WED/88 WITH 52 GALS OF 100 LL FUEL (6.5 HRS) FOR THE 4.5 HR FLT TO STL. CRUISE ALT WAS 7500' MSL. THREE HRS AFTER TKOF THE ENG BEGAN RUNNING EXTREMELY ROUGH. I DECLARED AN EMER BY CALLING THE SGF TWR. TWR HAD ME CONTACT SGF APCH. I WAS ASSIGNED A TRANSPONDER CODE AND GIVEN CLRNC FOR A STRAIGHT IN APCH TO RWY 19. WE LANDED SAFELY AT SGF. NO ONE WAS INJURED AND NO DAMAGE WAS SUSTAINED TO THE ACFT. INSPECTION OF THE ENG REVEALED METAL FRAGMENTS IN ALL 4 CYLINDERS AND THE OIL SCREEN. THE MECH BELIEVES THAT AN INTAKE VALVE FAILED. THE ENG MUST BE REPLACED. FROM TALKING WITH OTHER MECHS, I FEEL THAT THIS TYPE OF ENG FAILURE COULD HAVE BEEN PREVENTED IF THE MECH WHO PERFORMED MY ANNUALS HAD QUESTIONED THE LOW COMPRESSION ON THE #4 CYLINDER.

Data retrieved from NASA's ASRS site as of August 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.