Incident Summary
On 23 February 2018, a Bombardier DHC-8-402 aircraft was conducting a scheduled flight from Chișinău International Airport (LUKK) to Warsaw Chopin Airport (EPWA). During the approach to land in Warsaw at approximately 14:30 UTC, the flight crew initiated the landing gear extension procedure. After selecting the gear down, the crew observed that the nose landing gear was not indicating down and locked, as the NOSE indicator light remained illuminated with a red filter. The crew decided to execute a go-around.
Findings
Following the go-around, the crew employed the alternate landing gear extension method. The landing gear then extended and locked properly. A normal approach and landing were subsequently completed without further incident. The aircraft was handed over to maintenance personnel. The crew submitted an Aviation Safety Report (ASR).
Cause
The investigation determined that the inability to open the nose landing gear door using the primary method was caused by a malfunction of the nose landing gear door actuator (Part Number 47830-1) due to wear. The actuator was responsible for opening and closing the nose landing gear door.
Actions Taken
During the troubleshooting process, maintenance personnel inspected the nose landing gear door opening and closing mechanism. They found the actuator to be unserviceable, with a leak from the actuator assembly. The NLG DOOR ACTUATOR ASSY (P/N 47830-1) was replaced. It was noted that the leak from the actuator had not been detected or was not visible during the rectification of a previous fault related to the nose landing gear door mechanism's proximity sensor on 22 February 2018. The event was recorded in the operator's Safety Management System (SMS) database and classified according to the operator's criteria. The event was included in the aviation safety performance indicators (SPIs) monitored per the operator's Safety Management Manual. No safety recommendations were issued by the investigation commission.