Nov 29, 2019 12:30:00

In the final load test of Boeing 777X, it turned out that the door was blown away and there was a big crack in the fuselage, but there was no significant influence on the design

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Boeing 777X , a passenger aircraft under development by the American Boeing, was announced during the load test in September 2019 that the fuselage's cargo door was blown away. However, according to new information obtained by the Seattle Times, it was revealed that the door was blown away and that the fuselage of the fuselage had a large crack.

Boeing 777X's fuselage split severe during September stress test | The Seattle Times
https://www.seattletimes.com/business/boeing-aerospace/boeing-777xs-fuselage-split-dramatically-during-september-stress-test/

The Boeing 777X is scheduled to start operation in 2020, but during the final load test in September 2019, the cargo door of the fuselage was blown outward. However, it may be the final stage of a test that puts a much higher load than expected in commercial operation, and it is reported that the review of the delivery date has not been considered as 'the equipment design and the overall schedule of the test program are not significantly affected.' It was done.

777X cargo door breakage, rear fuselage decompression

However, according to a report by the Seattle Times on November 27, 2019, it was found that the damage to the aircraft during the test was greater than the actual report. The following image is a photograph showing the damage situation of the aircraft released by the Seattle Times, and you can see that the fuselage just behind the wing has a big crack. The Seattle Times said that the originally reported 'aircraft doors were blown out' was only secondary damage to the cracks that originally occurred on the fuselage.

This test was the final load test of the Boeing 777X, and was conducted in the control room by Boeing and Federal Aviation Administration (FAA) personnel. In the test, it was scheduled to pass if the aircraft was subjected to 1.5 times more load than the “limit load” that does not occur in normal flight and held for at least 3 seconds.

Boeing seems to have applied pressure to the wings and fuselage according to the requirements of the test, and also applied pressure inside the aircraft as a test outside the requirements. As a result, when the load equivalent to 1.48 times the critical load, that is, 99% of the load that passed the test, was applied, it seems that the aircraft was torn at the center of the fuselage. And the inside of the pressurized aircraft was depressurized all at once, and an explosive impact occurred, resulting in a situation where the cargo door was blown away.

The Seattle Times pointed out that the failure was only 1% until the FAA requirements were met, 'It's relatively good news for Boeing.' If the area around the keel where the problem occurred was strengthened and the aircraft was proved to be strengthened on the computer model, the Boeing 777X is expected to pass the test without retesting.

FAA engineers insist on the Seattle Times that Boeing has collected a large amount of data in this test and can use computer models to accurately analyze the failure. “The good news is that they can find and deal with problems. Boeing can find problems that can be corrected and strengthen the structure based on analysis,” said an FAA engineer.

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Although the Seattle Times asked for comments on Boeing, the details of the survey so far were not told, but the survey results as of November 26, `` This situation is the design of the Boeing 777X and He said that it would reinforce the previous evaluation that it would not have a major impact on preparation. Spokesman Paul Bergman said the Boeing 777X will fly for the first time in early 2020 and will be delivered to airlines in 2021.