Small aircraft has rough engine after departure. Returns to airport.

Attributes
ACN	124401
Time
Date	198909
Day	Thu
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : owd
State Reference	MA
Altitude	msl bound lower : 1000 msl bound upper : 1000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	general aviation : instructional
Make Model Name	Small Aircraft, High Wing, 1 Eng, Fixed Gear
Flight Phase	climbout : takeoff climbout : initial landing other
Flight Plan	VFR
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : instrument pilot : commercial
Experience	flight time last 90 days : 250 flight time total : 850
ASRS Report	124401
Events
Anomaly	aircraft equipment problem : critical other anomaly other
Independent Detector	other flight crewa
Resolutory Action	flight crew : declared emergency none taken : unable
Consequence	Other
Supplementary
Primary Problem	Aircraft

Narrative:

Upon departure out of owd, the aircraft I was flying began to develop a rough running engine. Thinking this roughness was due to spark plug fouling I requested to return to owd for a precautionary landing. I believe the cause of this was using 100LL fuel in a 80 octane engine. After landing I reviewed the aircraft documents and discovered the aircraft registration, the pink slip, had expired. Recommendations: 1) I feel the use of 100LL fuel in 80 octane engines should be reviewed to determine if this is a safe practice. 2) I recommend a longer grace period for the processing of registration certificates to prevent inadvertent paper violations.

Original NASA ASRS Text

Title: SMA HAS ROUGH ENGINE AFTER DEP. RETURNS TO ARPT.

Narrative: UPON DEP OUT OF OWD, THE ACFT I WAS FLYING BEGAN TO DEVELOP A ROUGH RUNNING ENG. THINKING THIS ROUGHNESS WAS DUE TO SPARK PLUG FOULING I REQUESTED TO RETURN TO OWD FOR A PRECAUTIONARY LNDG. I BELIEVE THE CAUSE OF THIS WAS USING 100LL FUEL IN A 80 OCTANE ENG. AFTER LNDG I REVIEWED THE ACFT DOCUMENTS AND DISCOVERED THE ACFT REGISTRATION, THE PINK SLIP, HAD EXPIRED. RECOMMENDATIONS: 1) I FEEL THE USE OF 100LL FUEL IN 80 OCTANE ENGS SHOULD BE REVIEWED TO DETERMINE IF THIS IS A SAFE PRACTICE. 2) I RECOMMEND A LONGER GRACE PERIOD FOR THE PROCESSING OF REGISTRATION CERTIFICATES TO PREVENT INADVERTENT PAPER VIOLATIONS.

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.