A BE-76 pilot receiving training experienced a nose gear collapse on takeoff roll. The reporter feels it was a system malfunction; but the landing gear lever was found in the up position.

Narrative

CFI/MEI and I took the airplane for a rental checkout and multi-engine currency. After doing steep turns; slow flight; a stall series (power-off and power-on); a VMC demonstration; engine out and shutdown procedures (with air-start) and a practice emergency descent; I proceeded to airport for 2 of the 3 landings required to complete the checkout. Weather conditions was clear VMC (VFR); runway was dry. First approach to landing was completely normal; GUMPS checks were performed at least three (3) times in the approach to landing and the first landing was normal. The CFI/MEI retracted the flaps in preparation for the take-off and I pushed the throttles to full power and had my other hand on the yoke in anticipation of take-off. When the airspeed was around 65 knots; the nose gear suddenly retracted and the airplane skidded to a stop after approximately 300'; once the plane was completely stopped; we looked at the panel and noted the landing gear selector in the UP position. At no time during the rollout did the CFI/MEI nor I touch the gear selector. It is possible that the selector may have been bumped with my knee; but the positive detent in the gear selector should have prevented that occurrence and on examination; the stop appeared to be worn. The gear selector was put in the DOWN position and the aircraft was made safe.