How much testing was actually done on the MD-11?
Posted by Dwilliamson5002@reddit | aviation | View on Reddit | 11 comments
Been looking around a bit, albeit yet not super hard, on some of the testing for the MD-11 to get it back in service. It does not seem to me they did a ton of actual in-flight testing? I could be wrong but it seems like more should have been done, especially with Boeing’s problems with safety and quality these days?
Probably would be super rare but if they get these all back in the air again and an engine falls off…
Seems like that is going to or should be a major problem for them?
victor_e_bull@reddit
OP here's a long discussion of the work FedEx and Boeing did before they resumed flying
https://www.freightwaves.com/news/fedexs-md-11-comeback-to-start-with-short-cargo-flight-to-miami
FZ_Milkshake@reddit
A mechanical part failed in a very specific way, they did analysis and fatigue testing on this part. You can't do that in flight.
Dwilliamson5002@reddit (OP)
TY. I knew there was more to it, but just seemed like more in-flight testing was needed seems like they just flew it around for a small bit and was like fuck it, just send it, but who I am really anyways? lol
FZ_Milkshake@reddit
You can't test this type of fatigue failure on the real product and you don't need to.
Mech_145@reddit
Also makes it way easier to put strain gauges and other test instrumentation on it
Holding_Short@reddit
How is “Boeing’s problems with safety and quality these days” relevant to a plane developed by a separate company forty years ago?
Nelik1@reddit
Actually, from what I understand, shockingly.
A lot of the cavalier attitude, prioritization of timeline over quality, and willingness to cut corners came directly from the McDonnell-Douglas leadership that was brought into Boeing post merger.
A lot of the culture issues at Boeing today were present at MD pre-acquisition, at least according to the small handful of documentaries and interviews I have seen.
That said, I don't think the FAA would allow an unproven repair following a failure like this. I am sure the new solution has been thoroughly analyzed and bench tested (and probably the old analysis revisited to see what they missed).
Dwilliamson5002@reddit (OP)
I’m pretty sure that’s how it went down when they merged. Boeing was about quality and safety. MD was about the money.
Just hard to trust the FAA these days when for a while they just let or hired Boeing do the testing and essentially buy certification or close to it. And with our current administration it is hard to just anything at all!
Nelik1@reddit
Obviously I don't have inside knowledge of what the recertification plan was for this aircraft. What I can say, is the timeline seems reasonable for a decent repair to be analyzed, tested, and installed.
Its a very simple mechanical connection with discreet loading, and is very easy to test on the bench in a representative way. Theres clean classical and finite element solutions to this problem that are well documented and understood.
My guess: -Design/Analysis of the new solution took 2 weeks. -Testing of the analysis took 1~2 months -The rest of the time was spent doing root cause analysis, tracing back the old analysis, and creating/submitting paperwork.
Dwilliamson5002@reddit (OP)
Boeing and MD merged? Didn’t Boeing design and make and test the bracket/parts? I would think if that bracket fails again then it is on Boeing? Why would they even fix it if it is not them? I have never taken a Jeep into a Toyota dealer for a recall or replacement part?
GGCRX@reddit
Because Boeing designed the fix?