Incident Overview
On August 28, 2017, at 15:10 UTC, shortly after takeoff from Warsaw Chopin Airport (EPWA) for a scheduled flight to Katowice (EPKT), the flight crew of a Bombardier DHC-8-Q400 observed two indicator lights illuminate during landing gear retraction. The amber "RIGHT MAIN GEAR DOOR NOT CLOSED" and red "RIGHT LANDING GEAR NOT LOCKED UP" warnings confirmed a problem with the right main landing gear.
Crew Actions
In response to the warnings, the crew immediately consulted the checklist and performed the alternate landing gear extension procedure. The aircraft returned to the departure airport, where an emergency landing was carried out without further incident.
Maintenance Findings
After landing, the aircraft was handed over to maintenance personnel. Inspection of the landing gear system revealed a cracked spring in the mechanism that locks the gear in the retracted position. This damage prevented the right main landing gear from retracting and locking properly, and also kept the gear door from closing.
Cause
The cause of the incident was damage to the spring in the landing gear locking mechanism, which prevented correct retraction and locking of the right main landing gear and closure of the gear door.
Post-Incident Actions
The operator recorded the event in its Safety Management System (SMS) database and classified it according to internal criteria. The incident was included in the operator's Safety Performance Indicators (SPIs), which are monitored as per the Safety Management Manual. No safety recommendations were issued by the investigation authority.