This story originally appeared on AirlineGeeks.com. The National Transportation Safety Board (NTSB) has determined that an improperly installed borescope plug was the cause of an engine fire on an Atlas Air Boeing 747 in January. The maintenance on the aircraft had been conducted just four days prior to the incident.

On January 18th, Atlas Air flight 3885 was en route from Miami to San Juan, Puerto Rico, when the crew received a fire alert for the No. 2 engine of the Boeing 747-8F at an altitude of approximately 3,000 feet. An emergency was declared, and the aircraft safely returned to Miami. Fortunately, no injuries were reported.

The NTSB's final report indicated that there were no signs of an uncontained engine failure. However, minor burn damage was observed on the thrust reverser fan duct of the GEnx engine. The aircraft was returned to service on January 27th, nine days after the incident.

According to the NTSB's findings, a third-party maintenance contractor was responsible for performing a borescope inspection on the No. 2 engine, which involved removing a plug. Both the mechanic and the inspector had certified that the inspection adhered to the standards outlined in the maintenance manual.

The investigation revealed that the removed plug was found loose within the engine cowling, and this dislodgement ultimately led to the fire.

The post 'NTSB Blames Boeing 747 Engine Fire on Shoddy Maintenance Work' originally appeared on FreightWaves.