When the landing gear was retracted after takeoff, the pilot found that the nose gear ‘down and locked’ green light remained on. During repeated gear extensions in preparation for landing, the pilot established that the nose leg had not locked down, despite the indicator light remaining on. The aircraft subsequently landed and the nose leg collapsed during the latter part of the landing roll.
It was found that the internal components of the nose gear downlock microswitch assembly were disrupted to the extent that the electrical outputs were random. A possible reason was that the switch was damaged during a previous accident.