Flight Crew Air Transport Pilot (ATP)
Situational Awareness
Aircraft Equipment Problem Less Severe
Aircraft Equipment Problem Dissipated; Flight Crew Executed Go Around / Missed Approach; General Maintenance Action
Aircraft
On approach in the landing configuration; around approximately 2000 feet MSL; there was a noise from outside the front of the aircraft; and the landing gear warning horn sounded for approximately 3 seconds. At the same time as the outside sound and warning horn; the First Officer (who was pilot flying) noticed the NLG red transit light flash on; then off; and concurrently the amber and green NLG lights extinguished then came back on. The First Officer and I quickly conferred and concluded that the NLG had tried to cycle its position to some degree. The First Officer had recently experienced a similar event on another aircraft. It was decided to discontinue the landing and perform a go-around and request vectors for another landing approach utilizing the alternate gear extension procedure. While being vectored back around for an approach and landing; we performed an alternate landing gear extension per the aircraft non-normal/emergency checklist. Upon completion of the gear extension; all indications were that the gear was down and properly configured; and I as pilot flying (per the checklist) made a normal approach and landing. An emergency was not declared for this event; nor was assistance requested once on the ground. Taxi to and parking at the gate was made on two engines without nose wheel steering; per procedure. Once parked at the gate with engines shut down; the First Officer promptly engaged the nose wheel locking mechanism; and main gear was subsequently pinned per the aircraft checklist. Presumed mechanical anomaly in landing gear operating and/or monitoring systems.
Dash 8-300 Captain experiences a momentary nose landing gear unsafe indication during approach after the gear had already been verified down and safe. A go-around is initiated and the gear is extended utilizing the alternate gear extension procedure.