Door blows out during ground test on Boeing 777X jet
Reportedly at 99% of target load.
Which, incidentally, is closer than Airbus got with the A380 wing test before being granted an exemption.
Boeing downplays impact of 777X load test "issue" - FlightGlobal
Which, incidentally, is closer than Airbus got with the A380 wing test before being granted an exemption.
Boeing downplays impact of 777X load test "issue" - FlightGlobal
According to Boeing's wording it happened during the "final load test" and it broke at 99 percent of whatever the goal was.
So what was the goal? Ultimate load? Limit load plus X? 1,3 max cabin pressure?
So what was the goal? Ultimate load? Limit load plus X? 1,3 max cabin pressure?
Intermediate testing is done to weed out design and materials issues.
This was the FINAL ground test for certification...no learning here, this is to show the ac meets specs. It blew on the blow test and as Boeing stated, they had to stop the test.
The final test for cert is to show that all of the other testing and design assumptions have passed, and the ac is ready to be cert to fly.
This reads that they stopped the test before it was completed, correct?
On the blow test, there are 3 parts..static, working load, and ultimate.
Static tests the normal pressure
Working load tests the assumes highest pressure the fuselage will have ONCE in its service.
Ultimate load tests the working load by 1.5 times.
Boeing claims it had to stop the test...at which point did it stop?
The wording, failed under much higher that normal operations, stil could mean the working load test.
Think about it, if it had failed under ultimate, 1.5...that could be understood, because ultimate at 1.5 is the assumed failure pressure.
Given all of the secrecy, lack of disclosure, and other issues, I tend to believe it failed before working load....
As noted by the "ex-VP" videos are online and the ground testing was usually a media event....this one was closed doors to regulators. (and it failed with all of the regulatory agencies present, )
Time for Boeing to start telling the truth.
This was the FINAL ground test for certification...no learning here, this is to show the ac meets specs. It blew on the blow test and as Boeing stated, they had to stop the test.
The final test for cert is to show that all of the other testing and design assumptions have passed, and the ac is ready to be cert to fly.
This reads that they stopped the test before it was completed, correct?
On the blow test, there are 3 parts..static, working load, and ultimate.
Static tests the normal pressure
Working load tests the assumes highest pressure the fuselage will have ONCE in its service.
Ultimate load tests the working load by 1.5 times.
Boeing claims it had to stop the test...at which point did it stop?
The wording, failed under much higher that normal operations, stil could mean the working load test.
Think about it, if it had failed under ultimate, 1.5...that could be understood, because ultimate at 1.5 is the assumed failure pressure.
Given all of the secrecy, lack of disclosure, and other issues, I tend to believe it failed before working load....
As noted by the "ex-VP" videos are online and the ground testing was usually a media event....this one was closed doors to regulators. (and it failed with all of the regulatory agencies present, )
Time for Boeing to start telling the truth.
Boeing only needs to report details to the certifying agency and not to the public or its competitors
The customers need assurances that a any process affecting their delivery is being followed.
If adjustments are called for and approved by the FAA then that may be reportable to all.
Moderator
To who?
Boeing only needs to report details to the certifying agency and not to the public or its competitors
Boeing only needs to report details to the certifying agency and not to the public or its competitors
That fact that some information finds its way in the public realm does not suddenly compel an applicant or authority to explain or justify the outcome of a certification test. I've witnessed many certification tests, both as in interested person, and a delegate of the authority. Some of the tests were not a pass, and some test articles were broken - that's the nature of testing! If a structural element failed at 99% of its predicted ultimate load, hats off to the engineers! A little redesign, with apparently valid design assumptions, and the product should be great. We can hardly have efficient aircraft when the structure has a capacity many times the ultimate load cases - it'll be needlessly heavy.
This.
That fact that some information finds its way in the public realm does not suddenly compel an applicant or authority to explain or justify the outcome of a certification test. I've witnessed many certification tests, both as in interested person, and a delegate of the authority. Some of the tests were not a pass, and some test articles were broken - that's the nature of testing!
That fact that some information finds its way in the public realm does not suddenly compel an applicant or authority to explain or justify the outcome of a certification test. I've witnessed many certification tests, both as in interested person, and a delegate of the authority. Some of the tests were not a pass, and some test articles were broken - that's the nature of testing!
I failed my first attempted certification test on the 747-8, even though we had done a verification test previously - the only time in my career I ever failed a cert test. We later determined that the problem was confined to specific OAT temperature band that we had been lucky enough (or unlucky - depending on you point of view) to encounter on the cert test - and it wasn't even my system at fault - it was the FMC. After reading my email to upper management informing them of the test failure, my supervisory pronounced me a 'Master of Understatement'
BTW, I flew a commercial flight out of Paine Field yesterday. I counted four completed 777-9X aircraft parked on the flightline (presumably without engines but from the angle I couldn't tell for sure).
Yes, still the old approach, What would pilots want to know about MCAS? What about structural integrity?
It should be a valid interest in a forum like this to want to find out more about what has happened aside from that carefully worded to downplay statement.
It should be a valid interest in a forum like this to want to find out more about what has happened aside from that carefully worded to downplay statement.
Back when I was an 'aerospace engineer' at Boeing, the FAA did look at our processes as well as designs. But that was something Boeing management pushed back against. Perhaps that was a mistake.
Originally Posted by lomapaseo
Boeing only needs to report details to the certifying agency and not to the public or its competitors
Last edited by WHBM; 13th Sep 2019 at 21:11.
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Well that's just silly hyperbole. Nobody is proposing that the structures handle 300% ("many times") of requirement. But we hope they will put a little bit of contingency in there. Maybe 110%. But the desperation to get it down to 100.001% of the requirement is what alas leads to this situation, where it fails at the 99% point. Which means, bluntly, it's a fail. And shows among other things overall poor design ability..
From an ignoramus point of view, I'd be astonished if they couldn’t. A seasoned pilot can look at an artist's impression and know if it would work-eventually you get a feel for the hidden structural attributes if you have pondered a few Flight International cutaway diagrams. Eventually even a dumb pilot gets a feel for skin thickness, rib dimensions and spar depths. Modulus, strength, deflections, etc. , Aside from materials, not much is new since the B-47
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Something else I am surprised no one has brought up.
The newer planes are designed to much finer tolerences, requiring precision machines to achieve those tolerences. Obviously the first few built for certification will receive more care to ensure that it is put together properly. But what happens when the planes go into production and become "mass produced"?
We have seen reports of Boeing accepting components for such newer planes that are not made according to specifications. When parts that were supposed to be computer cut were cut by hand. Where holes do not match up and have to be redrilled. Where parts that do not fit are hammered in to make them fit. https://www.sbs.com.au/news/sites/sb...ranscript.html
A carefully put together aircraft that fails at 99% highest test load may later become a bash-it-in-to-make-it-fit aircraft that fails at a much lower load .
The newer planes are designed to much finer tolerences, requiring precision machines to achieve those tolerences. Obviously the first few built for certification will receive more care to ensure that it is put together properly. But what happens when the planes go into production and become "mass produced"?
We have seen reports of Boeing accepting components for such newer planes that are not made according to specifications. When parts that were supposed to be computer cut were cut by hand. Where holes do not match up and have to be redrilled. Where parts that do not fit are hammered in to make them fit. https://www.sbs.com.au/news/sites/sb...ranscript.html
A carefully put together aircraft that fails at 99% highest test load may later become a bash-it-in-to-make-it-fit aircraft that fails at a much lower load .
MANY years ago, when I was designing inspection measurement equipment, a customer approached us to help him interpret an Airbus drawing. He dared not ask Airbus for clarification, because as a sub contractor he had been supplying the part for year(s) and feared opening an expensive can of worms. But none of my team could understand the drawing either, Airbus seem to have survived that one.
Has there been any extra information released about this cargo door yet?
Have Boeing confirmed if it was a main cargo door or the bulk cargo door? They have been surpisingly tight lipped about this incident.
I think there is a much bigger problem than just a cargo door.
Have Boeing confirmed if it was a main cargo door or the bulk cargo door? They have been surpisingly tight lipped about this incident.
I think there is a much bigger problem than just a cargo door.
Has there been any extra information released about this cargo door yet?
Have Boeing confirmed if it was a main cargo door or the bulk cargo door? They have been surpisingly tight lipped about this incident.
I think there is a much bigger problem than just a cargo door.
Have Boeing confirmed if it was a main cargo door or the bulk cargo door? They have been surpisingly tight lipped about this incident.
I think there is a much bigger problem than just a cargo door.
Has there been any extra information released about this cargo door yet?
Have Boeing confirmed if it was a main cargo door or the bulk cargo door? They have been surpisingly tight lipped about this incident.
I think there is a much bigger problem than just a cargo door.
Have Boeing confirmed if it was a main cargo door or the bulk cargo door? They have been surpisingly tight lipped about this incident.
I think there is a much bigger problem than just a cargo door.
https://simpleflying.com/boeings-777x-ripped-apart/
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Because the test was within 1% of its target pressure levels, the Seattle Times believes that the aircraft will not have to undergo a retest. While that might sound alarming to some, it’s important to remember that these pressure tests exert immense amounts of stress on the airframes, far more than would normally be encountered in a natural environment.