THE R LNDG GEAR OF AN SMA FOLDED AFTER LNDG.

Narrative

UPON LEVEL OFF AT 1800 FT ABOUT 1 1/2 MI N OF MARTHA LAKE; I PULLED PWR TO IDLE TO SIMULATE AN ENG FAILURE. THE AIRPLANE IS AN SMA WITH AN AUTOMATIC LNDG GEAR EXTENSION FEATURE. MY STUDENT PINNED THE OVERRIDE TO KEEP THE LNDG GEAR RETRACTED AND COMPLETED THE ENG RESTART PROC WHILE ESTABLISHING A GLIDE TOWARD THE ARPT. FLAPS WERE SET AT 10 DEGS ON ABOUT A 3/4 MI FINAL; FOLLOWED BY THE LNDG GEAR EXTENSION. I RECHKED THE LNDG GEAR SWITCH DOWN GREEN LIGHTS; AUX PUMP 'ON' AND OVERRIDE RELEASED AND DECIDED WE LOOKED OK FOR A FULL STOP LNDG. SPI EXTENDED 40 DEGS FLAPS ON SHORT FINAL AND THE TOUCHDOWN ABOUT 400 FT PAST THE THRESHOLD WAS IN A NOSE HIGH ATTITUDE AND SEEMED NORMAL. SHORTLY AFTER LNDG; THE R WING BEGAN TO LOWER AND THE LNDG GEAR WARNING HORN SOUNDED AS THE AIRPLANE PULLED TO THE R AND SLID TO A STOP ANGLED ABOUT 20 DEGS OFF RWY DIRECTION WITH THE R MAIN LNDG GEAR COLLAPSED ON THE GRASS. THE NOSE GEAR AND L MAIN LNDG GEAR REMAINED EXTENDED AND THE R GEAR WAS MANUALLY EXTENDED AND LOCKED TO CLR THE AIRPLANE FROM THE RWY. IN THIS CASE; THE GEAR DOWN INDICATIONS (LNDG GEAR SWITCH; GREEN LIGHTS; AND WARNING HORN) WERE POSITIVE; ALTHOUGH THE DOWN LOCK APPARENTLY RELEASED DURING ROLLOUT. DAMAGE WAS LIMITED TO THE R FLAP AND AILERON.