Dash 8-100
Flight Crew Air Transport Pilot (ATP)
Troubleshooting; Situational Awareness; Confusion; Human-Machine Interface
Aircraft Equipment Problem Critical
Flight Crew Overcame Equipment Problem
Human Factors; Aircraft
Our flight experienced an intermittent nose gear unsafe warning red light accompanied with a gear warning horn and gear handle light; on taxi to the gate after landing and engine shut down.I contacted dispatch and spoke with maintenance creating a maintenance write up. A discussion about ferrying the aircraft to a maintenance base with landing gear down for maintenance followed.  I expressed my concern to dispatch at that time that we would not be able to ferry the aircraft with the landing gear pinned down as we experienced in flight icing from approximately 8;000 feet MSL down below MEA in the area on arrival.  I requested dispatch and maintenance issue the permit so the flight could be completed with the gear retracted; knowing that if necessary we could use the alternate gear extension checklist to lower the gear if necessary.On climb out we retracted the gear before entering icing conditions.On arrival we selected the gear down; it extended normally and we achieved three green. Approximately 15 seconds later while accomplishing the landing checklist; the nose gear retracted with accompanying gear unsafe; gear door lights; gear handle light and gear horn sounding; until the nose gear door light and nose gear unsafe light extinguished. We felt the nose gear retract; and heard the sounds we would normally have expected to hear on gear retraction; indicating that the nose gear had actually retracted.The nose gear then extended and all lights extinguished except 3 green; gear horn silenced.Seconds later the nose gear retracted again with accompanying indications; several more times. I opened the nose gear alternate extend door and switched on the landing gear alternate verification lights which indicted the nose gear was not down and locked.; but the mains were.We performed an alternate gear extension per the abnormal checklist; and landed.
After encountering an intermittent gear unsafe light (after landing); the flight crew of a DHC-8 agreed to ferry the aircraft for maintenance. On that approach; the nose gear failed to remain extended. They conducted the alternate gear extension abnormal check list successfully; and landed without further incident.