NTSB Reveals Likely Cause of United Flight 328 Engine Fire

U.S. National Transportation Safety Board Chairman Robert Sumwalt said a preliminary assessment of the Pratt & Whitney engine that failed Saturday in a United Airlines Boeing 777-200 plane showed damage to the fan blades consistent with metal fatigue.

United Flight 328 from Denver to Honolulu turned around and safely landed at Denver International Airport with no injuries. But not before dramatic social media pictures and video chronicled the harrowing sequence of an engine on fire and debris falling from the sky onto a suburb in Denver.

United Airlines on Sunday announced it is grounding all 52 of the Boeing 777 airplanes powered by Pratt & Whitney Series 4000 engines in its fleet – 24 active and 28 in storage

Sumwalt made his remarks in a briefing on Monday night.

The Boeing 777-200 that United used on the flight was 26 years old. Sumwalt said he was unsure whether this incident is related to a similar engine failure on a United flight in February of 2018 in which a fracture in a fan blade caused by metal fatigue was found to be at fault.

A similar investigation is currently underway in Japan, where a Japan Airlines 777 with the same Pratt & Whitney engine failed in December. Investigators so far say they found two damaged fan blades, one with metal fatigue.

“What is important that we really truly understand the facts, circumstances and conditions around this particular event before we can compare it to any other event,” Sumwalt said.

Boeing recommended that airlines suspend the use of the planes temporarily until a cause is identified.