Pilot reported the engine lost power and began running roughly during initial climb; resulting in an...

Attributes
ACN	1705940
Time
Date	201911
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.Tower
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Small Aircraft
Operating Under FAR Part	Part 91
Flight Phase	Takeoff
Route In Use	None
Flight Plan	None
Component
Aircraft Component	Engine
Person 1
Function	Single Pilot Pilot Flying
Qualification	Flight Crew Private Flight Crew Flight Instructor
Experience	Flight Crew Last 90 Days 8 Flight Crew Total 650 Flight Crew Type 350
Events
Anomaly	Aircraft Equipment Problem Critical Deviation - Procedural Clearance

Narrative:

Takeoff roll was normal. On initial climb at approximately 400 ft. AGL; the engine lost power and started running roughly. Takeoff rpm was approximately 5;300 rpm and engine dropped to about 4;000 rpm. Told tower that I was having engine problems and needed to land immediately. A landing was made on the intersecting runway without incident or problem. The taxi back to the hangar was normal. I believe that this had something to do with the fuel system; even though the system was sumped with no visible contaminants immediately prior to the flight. The pre-takeoff run-up was normal. The engine ran normally at low rpm on the return to the hangar. Possibilities in my mind were fuel contaminants or possibly carburetor ice. I plan on removing the cowl and checking the fuel lines and then doing a full power run-up for about 5 minutes to see if the condition can be reproduced on the ground.

Original NASA ASRS Text

Title: Pilot reported the engine lost power and began running roughly during initial climb; resulting in an immediate return to landing.

Narrative: Takeoff roll was normal. On initial climb at approximately 400 ft. AGL; the engine lost power and started running roughly. Takeoff rpm was approximately 5;300 rpm and engine dropped to about 4;000 rpm. Told Tower that I was having engine problems and needed to land immediately. A landing was made on the intersecting runway without incident or problem. The taxi back to the hangar was normal. I believe that this had something to do with the fuel system; even though the system was sumped with no visible contaminants immediately prior to the flight. The pre-takeoff run-up was normal. The engine ran normally at low rpm on the return to the hangar. Possibilities in my mind were fuel contaminants or possibly carburetor ice. I plan on removing the cowl and checking the fuel lines and then doing a full power run-up for about 5 minutes to see if the condition can be reproduced on the ground.

Data retrieved from NASA's ASRS site 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.