Narrative:

Flight instructor student were on a flight lesson when they experienced partial power loss. Instructor called XXX approach control and declared an emergency. Was vectored to nearest airport and made landing without incident. The fuel system was inspected and it was found that the finger screen in the carburetor was filled with a lint like substance to the point that fuel flow was restr. The fuel system was drained and cleaned. No further contamination was found. The disturbing problem is that this lint had passed through the gascolator screen without being trapped as designed. The fuel system was refilled. The aircraft was test flown and returned to service after operating normally. 6 other flight school aircraft were checked for the same problem or possible fuel contamination and none was found in any other aircraft. It is this mechanic's intention to continue to pull the finger screen at frequent intervals to insure that no further contamination in the system exists.

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Original NASA ASRS Text

Title: A C152 CREW HAD TO DECLARE AN EMER DUE TO A PARTIAL PWR LOSS. THEIR FUEL WAS CONTAMINATED WITH LINT.

Narrative: FLT INSTRUCTOR STUDENT WERE ON A FLT LESSON WHEN THEY EXPERIENCED PARTIAL PWR LOSS. INSTRUCTOR CALLED XXX APCH CTL AND DECLARED AN EMER. WAS VECTORED TO NEAREST ARPT AND MADE LNDG WITHOUT INCIDENT. THE FUEL SYS WAS INSPECTED AND IT WAS FOUND THAT THE FINGER SCREEN IN THE CARBURETOR WAS FILLED WITH A LINT LIKE SUBSTANCE TO THE POINT THAT FUEL FLOW WAS RESTR. THE FUEL SYS WAS DRAINED AND CLEANED. NO FURTHER CONTAMINATION WAS FOUND. THE DISTURBING PROB IS THAT THIS LINT HAD PASSED THROUGH THE GASCOLATOR SCREEN WITHOUT BEING TRAPPED AS DESIGNED. THE FUEL SYS WAS REFILLED. THE ACFT WAS TEST FLOWN AND RETURNED TO SVC AFTER OPERATING NORMALLY. 6 OTHER FLT SCHOOL ACFT WERE CHKED FOR THE SAME PROB OR POSSIBLE FUEL CONTAMINATION AND NONE WAS FOUND IN ANY OTHER ACFT. IT IS THIS MECH'S INTENTION TO CONTINUE TO PULL THE FINGER SCREEN AT FREQUENT INTERVALS TO INSURE THAT NO FURTHER CONTAMINATION IN THE SYS EXISTS.

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.