Metal fatigue apparently played a role in the explosion of the engine of a United Airlines flight during Denver on Saturday, National Transportation Safety Board chairman Robert Sumwalt said at a virtual press conference Monday night . The explosion of Flight 328 caused parts of the PW4000 Pratt & Whitney engine casing to rain in suburban neighborhoods.
According to CBS Denver, Sumwalt said the engine exploded sharply and began vibrating about four minutes after the takeoff of Denver International Airport. He said the plane was about 12,000 feet above the houses at the time.
Sumwalt said two blades of the fan on the engine broke: one at the base where the hub is located and the second halfway. He said the first blade caused “overload damage” to the second blade.
NTSB
One of the leaves was found on a football field.
Sumwalt said investigators will try to determine how long the leaves had suffered from fatigue.
Federal Aviation Administration records show the plane involved was nearly 26 years old, according to CBS Denver, but FAA and NTSB officials said they could not clarify whether the failing engine was an original part or not. ‘installed later.
Photographs taken Saturday after the plane returned to Denver airport show an open hole under the right wing, suggesting some of the engine debris hit the plane itself.
NTSB
Sumwalt acknowledged that the lower body of the plane was damaged, but said the damage was not structural. The damaged part is a composite fairing that smooths the plane to make it more aerodynamic.
Sumwalt said the fire hose was activated in the cabin and two fire bottles were unloaded into the engine. He said the fuel flow was off and investigators will study what continued to fuel the fire despite precautions being taken.
The engine test will include a review of your maintenance history.
Sumwalt added that the agency will compare this event with others from the past.
“Our mission is to understand not only what happened, but also why it happened, so that we can prevent it from happening again,” Sumwalt stressed.
More than 200 passengers were traveling on the flight to Hawaii. No one was injured on the plane or on the ground. The plane returned to the airport safely about 20 minutes after takeoff.
The Denver incident happened one in December that involved a Japan Airlines 777 with the same type of engine and an engine problem on a February 2018 United flight.
“There could be a common theme“ between the three incidents, ”but until the investigation is complete, we don’t know,” Scott Hamilton of the aviation news site Leeham News said.
Boeing said Monday all 128 of the 777s with the same Pratt & Whitney engines landed around the world after Saturday’s emergency landing. Sixty-nine were in service and 59 in storage.
In addition to United, which took 24 aircraft out of service, the affected airlines included Japan Airlines and All Nippon of Japan and Asiana and Korean Air of South Korea.
Egyptian state newspaper Al Ahram reported on Monday that the national company Egyptair is landing four planes with the Pratt & Whitney engine, even though they were not in service, a source close to the manufacturer said.
British Transport Secretary Grant Shapps announced a temporary ban on entering UK airspace with Pratt & Whitney 4000-112 series powered aircraft.
– France-Presse contributed to this report.