SMA ON PLT CURRENCY FLT LANDS GEAR UP.

Narrative

THE PF THE ACFT HAD APPROX 500 HRS IN HIS PLANE. HE HAD SURGERY 6 MONTHS EARLIER AND HE INVALIDATED HIS MEDICAL WHICH HE EXPLAINED AFTER THE FLT HAD BEGUN. HE SAID HE WANTED TO PRACTICE AIR WORK AND TKOF AND LNDGS. WE PROCEEDED With THE AIR WORK COMPLETED IT AND THEN WENT TO PURCHASE FUEL. AFTER PURCHASING FUEL WE DID A TKOF AND LNDG BEFORE PROCEEDING TO GROTON FOR TWR WORK AND TKOF AND LNDGS. AT GROTON WE DID ONE TOUCH AND GO AND ON THE DOWNWIND THE PF SAID HE WANTED TO MAKE A FULL STOP LNDG. ABOUT MIDFIELD THE TWR TOLD AN ACFT MAKING AN IFR PRACTICE APCH TO RWY 5 TO EXECUTE A R CLBING TURN. WE WERE ON L DOWNWIND FOR 33 WHICH HEADED THE OTHER ACFT TOWARDS US. I TOLD THE PLT I WOULD WATCH THE OTHER AIRPLANE. HE CALLED OUT GEAR DOWN FOLLOWED SHORTLY BY CALLING OUT FLAPS DOWN. SHORTLY AFTER THE OTHER AIRPLANE WAS CLR OF US AND THE TWR GAVE US OUR SEQUENCE FOR LNDG. WE FOLLOWED THE OTHER ACFT AND THE PLT AND I DID A 'GUMP' CHK. AS WE CONTINUED THE APCH WE WERE LOW SO THE PLT SAID HE WAS RETRACTING SOME FLAPS AND ADDING PWR. THE CORRECTION WAS TOO MUCH SO HE ADDED FULL FLAPS AND REDUCED PWR TO 'IDLE.' I THOUGHT IT WAS IDLE. THE PLT DID A VERY NICE FLARE AND WE TOUCHED DOWN AND SLID SIDEWAYS. WE SHUT THE ACFT DOWN (ALTHOUGH THE ENG HAD OBVIOUSLY STOPPED) AND GOT OUT. THIS ACFT HAS HAD 2 PREVIOUS GEAR UP LNDGS. FURTHER; THERE WAS NEVER ANY WARNING HORN UNTIL WE WERE GOING THROUGH THE SHUT DOWN CHKLIST; IT IS SUPPOSED TO COME ON AT 18 INCHES AS ADJUSTED ON A THROTTLE SENSOR.