Small aircraft pilot has rough engine on takeoff. Turns to land on cross runway.

Attributes
ACN	155143
Time
Date	199008
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : sac
State Reference	CA
Altitude	agl bound lower : 250 agl bound upper : 300
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : sac
Operator	general aviation : personal
Make Model Name	Small Aircraft, High Wing, 1 Eng, Fixed Gear
Flight Phase	climbout : initial climbout : takeoff
Flight Plan	VFR
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : private
Experience	flight time last 90 days : 80 flight time total : 175 flight time type : 175
ASRS Report	155143
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 none taken : unable other
Consequence	Other
Supplementary
Primary Problem	Aircraft

Narrative:

Small aircraft was in rotation from my based airport, sea runway 20 when I seemed to feel a small vibration. My tachometer was 2-4 hundred rpms less than normal. At 250'-300' AGL the engine was rough. I called the tower. Tower cleared me to land on runway 34. I taxied and tied down. The following day 8/90 aircraft was taken (taxied) to FBO. Fuel system is being checked, electrical system, propeller is being reconditioned also. Aircraft is at FBO at this time. Callback conversation with reporter revealed the following information. Reporter states he is very upset with FBO. Same thing happened again since this report only at night. He has replaced magnetos, carburetor, generator and now working on ignition. He is an automatic repair man and told the mechanics that ths is not a fuel problem but an ignition problem by the way it feels. Now finally FBO is looking at the ignition system and has found terrible 'gunk' in the switching mechanism. Has decided he will not night fly or venture near mountains until aircraft has about 10 hours on it after this repair.

Original NASA ASRS Text

Title: SMA PLT HAS ROUGH ENGINE ON TKOF. TURNS TO LAND ON CROSS RWY.

Narrative: SMA WAS IN ROTATION FROM MY BASED ARPT, SEA RWY 20 WHEN I SEEMED TO FEEL A SMALL VIBRATION. MY TACHOMETER WAS 2-4 HUNDRED RPMS LESS THAN NORMAL. AT 250'-300' AGL THE ENG WAS ROUGH. I CALLED THE TWR. TWR CLRED ME TO LAND ON RWY 34. I TAXIED AND TIED DOWN. THE FOLLOWING DAY 8/90 ACFT WAS TAKEN (TAXIED) TO FBO. FUEL SYS IS BEING CHKED, ELECTRICAL SYS, PROP IS BEING RECONDITIONED ALSO. ACFT IS AT FBO AT THIS TIME. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO. RPTR STATES HE IS VERY UPSET WITH FBO. SAME THING HAPPENED AGAIN SINCE THIS RPT ONLY AT NIGHT. HE HAS REPLACED MAGNETOS, CARB, GENERATOR AND NOW WORKING ON IGNITION. HE IS AN AUTO REPAIR MAN AND TOLD THE MECHS THAT THS IS NOT A FUEL PROB BUT AN IGNITION PROB BY THE WAY IT FEELS. NOW FINALLY FBO IS LOOKING AT THE IGNITION SYS AND HAS FOUND TERRIBLE 'GUNK' IN THE SWITCHING MECHANISM. HAS DECIDED HE WILL NOT NIGHT FLY OR VENTURE NEAR MOUNTAINS UNTIL ACFT HAS ABOUT 10 HRS ON IT AFTER THIS REPAIR.

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.