PPRuNe Forums - View Single Post - Door blows out during ground test on Boeing 777X jet
Old 28th Nov 2019, 21:47
  #137 (permalink)  
tdracer
 
Join Date: Jul 2013
Location: Everett, WA
Age: 64
Posts: 2,597
Originally Posted by turbidus View Post
Aside from the conspiracy theories, the test is a single event test, not a repetitive or cyclical test.

Slowly bringing the ac up to 1.5 loading really doesnt provide a real test of conditions.
I think there is quite a bit of value in repetitive testing to the typical loading, many issues found in the field may have been avoided. having driven through quite a bit of turbulence, I always wonder about the stresses on the airframe.
Apples and Oranges. The test is question is 'ultimate load' - stress to 1.5x the max anticipated load and often to failure even if it's higher than the 1.5x requirement. A different airframe will be used for fatigue life testing, running the airframe through tens of thousands of simulated flight cycles - a test that takes many months to complete. That being said, fatigue life testing is a bit of a black art - accurately simulating actual flight loads is non-trivial.

BTW, for all the Boeing bashing going on, I notice this little tidbit apparently escaped notice:
At the same time, the fuselage was bent downward at the extreme front and aft ends with millions of pounds of force. And the interior of the plane was pressurized beyond normal levels to about 10 pounds per square inch not typically a requirement for this test, but something Boeing chose to do.
In other words, Boeing had previously done the 1.5x pressurization test - and passed. Then, although it's not a regulatory requirement, they again pressurized the fuselage to 1.5x when they did the wing ultimate load test - when it failed at 99% of target.
Oh, and for all the bitching about 'self certification' - there were six FAA people observing the test when the failure occurred.

Oh Grebe, the first 767 - VA001 - was not sold to United. It was initially kept by Boeing for use as a flying test bed, before being modified to the AOA (Airborne Optical Adjunct) test aircraft as part of Reagan's 'Star Wars' initiative.



Last edited by tdracer; 28th Nov 2019 at 22:00.
tdracer is online now