RIGHT MAIN GEAR COLLAPSED ON ROLL OUT AFTER LNDG.

Narrative

THE PURPOSE OF ONE FLT WAS DUAL INSTRUCTION WITH SPECIAL EMPHASIS ON EMER LNDG PROCS. THE WX WAS VFR; WITH GUSTY WIND AVERAGING ABOUT 15 KTS. WE HAD ALREADY EXECUTED 2 SIMULATED EMER LNDGS (PWR OFF) THAT HAD GONE WELL. WE THEN ENTERED ONE PATTERN AT A LCL UNCTLED ARPT AND SHOT 3 LNDGS AIMING FOR ACCURACY. THE CONDITIONS WERE SOMEWHAT CHALLENGING BECAUSE OF GUSTY XING CONDITIONS. AFTER ONE THIRD TOUCH AND GO; JUST AS I WAS TURNING XWIND; AT ABOUT 600' AGL; THE INSTR PULLED THE PWR TO SIMULATE ENG FAILURE ON TKOF. WE BANKED STEEPLY BACK TO THE ARPT WHILE SIMULTANEOUSLY LOWERING GEAR AND FLAPS. BOTH OF US WERE OCCUPIED WITH THE TASK OF PLTING THE PLANE SAFELY BACK TO THE ARPT AND EXECUTING A DOWNWIND XWIND LNDG. IT SEEMS NEITHER OF US CHKED THE 'GEAR SAFE' LIGHT. WE LANDED AND BEGAN ROLLOUT; WHICH CONTINUED FOR ABOUT HALF THE NORMAL ROLLOUT DISTANCE. THE ACFT THEN VEERED RIGHT OFF THE RWY AND ONTO A TXWY. AFTER IT CAME TO REST WE EXITED HASTILY AND FOUND THAT THE RIGHT GEAR HAD FOLDED BACK INTO THE WELL. CONTRIBUTING FACTORS: WE HAD BEEN PRACTICING EMERS THAT HAD INCLUDED HAVING THE GEAR WARNING HORN SOUNDING FOR SEVERAL MINS. ALTHOUGH NEITHER OF US ARE SURE; THE HORN WAS PROBABLY SOUNDING AND WE TUNED IT OUT; HAVING ALREADY BECOME HABITUATED TO IT. IT IS POSSIBLE THAT THE GEAR LEG DID NOT LOCK BECAUSE OF THE FORCES CAUSED BY THE BANK WHILE IT WAS IN THE PROCESS OF EXTENSION. IT WAS ON THE OUTSIDE OF THE TURN. THE MECH IS INVESTIGATING THIS AND OTHER POSSIBILITIES. MORAL OF STORY: 1) UNUSUAL PROCS PRACTICED SELDOM OPEN DOOR FOR PLT ERROR. 2) AS ALWAYS; DO GUMP CHK BEFORE EVERY LNDG. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING: RPTR QUOTED MECHS LOGBOOK ENTRY AS 'INTERMITTENT OPERATION OF MAIN CONTACTOR AND OF WARNING HORN.'