What happened
On June 8, 2016, during the boarding process at Warsaw Chopin Airport (EPWA), ground personnel and a mechanic identified symptoms of low pressure in the right nose gear tire of a Bombardier DHC-8-400 operated by PLL LOT SA.
Prior to this discovery, both a walk-around inspection performed by the ground handling agent and a pre-flight inspection conducted by the First Officer approximately thirty minutes earlier had failed to reveal any issues with the tire pressure. Upon confirming the low pressure, the mechanic determined that both nose gear tires required replacement.
As a result of the finding, passengers were temporarily bussed to the terminal while the maintenance work was performed. The flight eventually departed following the tire replacement, though the delay impacted the original schedule. An Air Safety Report (ASR) was filed following the completion of the flight.
The investigation
The investigation, conducted by the operator, focused on the timeline of the inspections and the sudden loss of pressure. The inquiry established that the tire pressure was within normal parameters during the inspections performed by the handling agent and the flight crew shortly before the issue was noted by the ground crew during boarding.