PIPISTREL LSA SRL SINUS near Kingsford, MI — 2023-04-13

Probable cause

The failure of maintenance personnel to properly secure the left carburetor bowl cover, which resulted in an engine fire before takeoff.

NTSB narrative

The pilot stated the engine lost power as he increased power for takeoff. The engine could not be restarted, and the airplane was pushed off the runway onto a taxiway. The pilot allowed the engine to cool and then restarted the engine. The engine ran smoothly for about one minute. When engine power was increased above 4,000 rpm, the engine lost power again. The pilot performed 2 additional engine starts, which also resulted in the engine quitting above 4,000 rpm. The pilot then noticed white smoke emitting from the engine compartment. A fire ensued that resulted in substantial damage to the motorglider. Postaccident examination of the engine revealed that the right carburetor bowl cover was attached to the carburetor bowl but the carburetor bowl cover retention clip was not in its secure position on the bowl cover. The left carburetor bowl cover was missing and was not recovered; it most likely fell out of the motorglider or was dislodged from the airplane when the fire was being extinguished. An unsecured bowl cover would have allowed fuel to leak onto hot exhaust pipes, resulting in a fire. Neither carburetor had optional carburetor drip trays installed to mitigate the risk of an engine fire from fuel leaking onto the engine exhaust from the carburetors by directing it away from the exhaust and overboard, which may have prevented the accident. Engine logbook entries showed that the carburetor bowl covers were removed during recent maintenance. It is likely that the covers were not properly reinstalled during that maintenance.

Analysis

Primary failure mode

Engine power loss

First missed decision gate

Proper maintenance of carburetors could have prevented engine power loss.

NTSB coding

• Powerplant sys/comp malf/fail · Taxi-into takeoff position
• Maintenance

Evidence available

• Video
• FDR / data
• Photos
• 9 docket documents

Docket documents9

• PILOT/OPERATOR AIRCRAFT ACCIDENT REPORT, NTSB FORM 6120.1form
• ENGINE LOGBOOKother
• RECORD OF CORRESPONDENCE - PIPISTRELother
• RECORD OF CORRESPONDENCE - ROTEC FLIGHT SAFETYother
• RECORD OF EXAMINATIONother
• PHOTO LOGphotos
• PHOTO LOG 2photos
• COCKPIT DISPLAY RECORDED DATA SPECIALIST'S FACTUAL REPORTreport
• AIRPORT VIDEO OF AIRCRAFT FIREvideo

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