Incident Overview
On 16 September 2015, an Embraer 190 aircraft (registration SP-LND) operated by LOT Polish Airlines was climbing after departure from Amsterdam (AMS) to Warsaw (WAW) when the Crew Oxygen Low Pressure (CREW OXY LO PRESS) caution appeared on the Engine Indication and Crew Alerting System (EICAS). The flight crew followed the applicable checklist and decided to continue the flight at a lower altitude of FL100 in accordance with the Quick Reference Handbook (QRH). After landing, an Air Safety Report (ASR) was filed.
Previous Maintenance Actions
The aircraft had experienced the same oxygen system issue several times before the incident. Maintenance records show the crew oxygen bottle was serviced on 9, 12, and 14 September 2015. On 15 September, during investigation, a leak was found from the captain's mask stowage box, and the box was replaced. On 17 September, the first officer's full-face mask sweep was replaced due to a leak. Additional servicing occurred on 18 September, and on 23 September a leak check according to the Fault Isolation Manual found no signs of leakage.
Findings and Cause
Despite the earlier maintenance actions, the crew oxygen low pressure warning recurred on 16 September. A subsequent analysis aimed to locate the source of the leak. The investigation determined that the leak originated from the first officer's oxygen mask. After the mask was replaced, no further signs of leakage were detected, and the problem did not recur.
Preventive Measures
The incident was recorded in the Safety Management System (SMS) database and will be included in the Safety Performance Indicators (SPI) monitored under the Aviation Safety Management Manual. No safety recommendations were issued by the investigating commission.