AMPHIBIAN HAS GEAR DOWN LIGHTS BUT GEAR COLLAPSES ON ROLL OUT WHEN BRAKES APPLIED.

Narrative

BEFORE LNDG GEAR WAS PUT DOWN; GOT GREEN LIGHT; VISUAL SHOWED ALL GEAR DOWN. AFTER LNDG ON GEAR I PUT ON THE BRAKES AND THE GEAR WENT UP LAYING THE AIRPLANE ON ITS KEEL (FLYING BOAT). WE HAD TO CLOSE THE ARPT AS MEN AND EQUIP WERE ON THE RWY TO JACK IT BACK UP. NO DAMAGE WAS SUSTAINED. UPON INSPECTION IT APPEARED THAT THE MICRO SWITCH MAY HAVE LOOSENED INDICATING GEAR DOWN AND LOCKED PREMATURELY (THIS WAS FIXED). I SUGGEST INSPECTION OF (GEAR MICRO SWITCH) ADJUSTMENT ON THIS AIRPLANE EVERY 25 HRS. THE ACFT IS AN AMPHIBIAN. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATES MECH GAVE A WRITTEN RPT STATING THIS MICRO SWITCH WILL OCCASIONALLY GIVE PREMATURE LIGHT INDICATION BUT GEAR STOPS BEFORE LOCKED. VISUALLY GEAR APPEARS TO AGREE WITH LIGHTS AND NO WAY TO KNOW IT IS NOT LOCKED. NO REAL DAMAGE TO ACFT; JUST SCRAPED THE KEEL A BIT. RPTR FEELS THE WORD SHOULD BE SPREAD AND POSSIBLY A REQUIREMENT TO ADJUST EVERY 25 HRS TO ELIMINATE SUCH INCIDENTS. THERE ARE STILL ABOUT 300 OF THESE AMPHIBIANS STILL FLYING.