A PA24-250 LANDED GEAR UP FOLLOWING A LNDG CHKLIST PERFORMANCE VERIFIED BY THE PLT AND INSTRUCTOR. A LNDG GEAR CIRCUIT BREAKER POPPED.

Narrative

ON DEC/XA/06; I DEPARTED ZZZ IN ACFT X; A PIPER COMANCHE 250; FOR A FLT BACK TO ZZZ1 WHERE THE ACFT IS BASED. ON THE FLT. I PRACTICED SOME HOLDING PROCS UNDER VFR CONDITIONS (A HOOD WAS NOT USED). BEFORE ENTERING CLASS D AIRSPACE; I RECEIVED CURRENT ATIS. TWR CLRED ME FOR RWY 28R. I COMPLETED MY PRE LNDG (GUMP) PROC: FUEL SELECTOR -- CHK. BOOST PUMP -- ON. GEAR SWITCH -- DOWN. MIXTURE -- FULL RICH. PROP -- IN (HIGH RPM). I LINED UP ON RWY 28R. AT THE FLARE ON FINAL; LOUD NOISES WERE HEARD AS THE ACFT SLID TO A STOP. AFTER THE ACFT STOPPED; I CONFIRMED THAT THE LNDG GEAR SWITCH WAS IN FACT DOWN. I THEN FOUND A SET OF TERMINAL PROC PUBS WEDGED BTWN THE LNDG GEAR EXTENSION HANDLE AND THE FLOOR. LATER INSPECTION FOUND THE LNDG GEAR CIRCUIT BREAKER HAD BEEN TRIPPED. SUPPLEMENTAL INFO FROM ACN 721195: I HAD COMPLETED AN INFLT TRAINING PORTION OF THIS FLT; AND WE WERE RETURNING TO THE HOME BASE ARPT WHEN THIS GEAR UP LNDG OCCURRED. THE OWNER AND PIC AT THE TIME OF THE INCIDENT HAD GONE THROUGH HIS PRE LNDG CHKS OUT LOUD AND I HEARD EACH OF HIS AURAL CHKS (BOOST PUMP; GAS ON FULLEST TANK; UNDERCARRIAGE OR GEAR DOWN; MIXTURE RICH; AND SEATBELTS FASTENED). AFTER THE GEAR UP LNDG WE DISCOVERED THAT THE CIRCUIT BREAKER HAD POPPED (WHEN UNKNOWN) AND THE LNDG GEAR WAS STILL IN THE 'UP' POS. THE PIC ALSO DISCOVERED AFTER LNDG THAT SOMETHING HAD WEDGED BTWN THE LNDG GEAR HANDLE AND THE FLOOR.