BEECH 76 DUCHESS; NOSE GEAR COLLAPSED DURING TKOF ROLL DUE TO THE TRAINEE'S KNEE INADVERTENTLY PUSHED THE GEAR POS SELECTOR TO THE UP RETRACTED POS.

Narrative

I WAS GIVING A STUDENT INSTRUCTION IN THE DUCHESS BE76. AFTER STARTING ENGS WE VERIFIED THE GEAR SELECTOR LEVER WAS IN THE DOWN POS. FOLLOWING CHKLIST; WE TAXIED INTO POS AND HOLDING FOR IFR RELEASE. UPON RECEIVING CLRNC TO TAKE OFF; STUDENT RAN DUCHESS UP TO 2200 RPM'S AND AFTER CHKING ENG GAUGES IN SCREEN; RELEASED BRAKES AND ADDED FULL PWR STARTING OUR GND ROLL. I VERIFIED THAT THE AIRSPD WAS ALIVE AND INSTRUCTED STUDENT TO ROTATE AT 71 KTS. THEN AT THAT POINT THE NOSE SMASHED ONTO THE RWY. THEN I FOLLOWED PROCS TO SECURE BOTH ENGS AND PLANE. THE PLANE CAME TO A SLIDING STOP ON THE RWY. WHILE GOING THROUGH CHKLIST; I NOTICED THAT THE LNDG GEAR LEVER WAS IN THE 'UP' POS. WHAT HAPPENED IS THAT THE SAFETY SWITCH ON THE LNDG GEAR LEVER; WHICH PREVENTS THE LNDG GEAR LEVER FROM MOVING TO THE 'UP' POS; WAS WORN SO MUCH THAT IT DIDN'T WORK ANYMORE. STUDENT IS A SHORT MAN. HE NEEDS TO PULL THE SEAT ALL THE WAY UP AND AFTER INVESTIGATION HIS R KNEE IS JUST BARELY TOUCHING THE LEVER. THE LEVER WAS IN THE 'DOWN' POS PRIOR TO OUR GND ROLL. STUDENT'S KNEE BUMPED INTO THE LNDG GEAR LEVER WHILE HE WAS TRANSITIONING HIS FEET FROM THE BRAKES TO THE RUDDERS FOR GND ROLL. WE RE-ENACTED THIS EVENT AFTER THE INCIDENT AND DISCOVERED THAT HIS KNEE EASILY BUMPED THE LEVER TO THE 'UP' POS CAUSING THE NOSE GEAR TO RETRACT AT 59-63 KIAS. THE DUCHESS IS SO NOSE HVY; I HAD NO TIME OR INDICATION THAT THE NOSE WAS ABOUT TO DROP. WHILE I WAS LOOKING AT THE AIRSPD INDICATOR; THE NOSE HIT THE RWY IN A MATTER OF A SECOND.