Date: 201202
Local time of day: 1801-2400
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Night
Aircraft: Dash 8-200
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Final Approach
Airspace: Class D ZZZ
ATC / advisory: Tower ZZZ
Aircraft component: Main Gear
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: First Officer
Reporter qualification: Flight Crew Commercial
Human factors: Workload; Training / Qualification; Troubleshooting; Situational Awareness; Distraction
Anomaly: Aircraft Equipment Problem Critical
Detector: Automation Aircraft Other Automation; Person Flight Crew
When detected: In-flight
Result: Flight Crew FLC complied w / Automation / Advisory; Flight Crew Landed in Emergency Condition; Flight Crew Took Evasive Action; General Maintenance Action; General Declared Emergency
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: All applicable checklists were complete. We began a visual approach and I called for the pilot not flying to extend the landing gear. Upon extension; the right main gear failed to indicate the 'Down and Locked' position. The gear panel indicated left main and nose gear 'Down and Locked' the right main 'Unsafe' and the Gear-in-Transit light illuminated. We reported the malfunction to the Tower and executed a Go-Around; leaving the landing gear in the position indicated. Once established in the airport traffic pattern; the pilot not flying contacted our Dispatch and Maintenance for input. We also contacted the Flight Attendant to ask her to confirm the right main gear was down. She confirmed that the gear appeared to be down. We executed a low approach and the Tower stated that they agreed the gear appeared to be down. We performed the Alternate Gear Extension Checklist in an effort to get the right main to indicate 'Safe.' The gear did not indicate 'Safe' following the procedure. We declared an emergency; asked for the fire trucks and briefed the Flight Attendant. We asked the Flight Attendant to move all passengers out of the propeller arc in case the landing gear collapsed upon touchdown. Additionally; we informed her that we were going to brace for landing. We then briefed the passengers via PA as to the situation and the decision to brace. With all checklists complete and the cabin prepared we began our approach. We made the landing as normal as possible with flaps set to thirty-five to achieve the slowest possible speed at touchdown. The airplane was flown to touchdown such that all weight was kept off of the right main for as long as possible. We stopped on the runway and shutdown the airplane. Upon inspection; it was determined that the gear had not achieved the locked position and we were unable to pin the right main gear. We pinned the left main gear. The right main gear required maintenance action to successfully insert the gear pin. We contacted Maintenance and they requested we start the number two engine in order to energize the number two hydraulic system and keep hydraulic pressure on the landing gear. The seventeen passengers and Flight Attendant were deplaned and transported to the terminal via shuttle bus. Once the shuttle bus was clear of the aircraft; the on-site mechanic was able to pin the right main gear. The gear pin was inserted into the right main and the gear indications turned from 'Unsafe' with the In-Transit light illuminated; to 'Down and Locked;' In-Transit light out. Having determined the landing gear to be safe; we taxied the aircraft to the gate for further maintenance action.




Synopsis: A DHC8-200 Right Main Landing Gear indicated unsafe on approach so an emergency was declared; the checklist completed and after landing on the runway a Mechanic was unable to install the gear pin until all passengers were removed. After the pin was installed the gear indicated down and locked.