system

Awesome title/photo combination

system

So what was the fix?

Oscar-Romeo

Yes, what was the fix, the article left us wondering.

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To the above, for further reading, see FR Doc Nos: 2022-05296, 022-05295, 022-05309

FAA is requiring ultrasound and TAI inspection of fan blades in some variants of PW4000 engines, modification of engine inlets to withstand fan blade separation, installation of debris shields on thrust reverser inner walls, inspection of the fan cowl doors for moisture ingress, and checks of the response of the hydraulic pump shutoff valves to engine fire handle input.

There may be more, that’s just what I found in a minute or so of searching via the terms 777-200 and PW4077. A redesign of the fan blade would be necessary to correct this LCF issue, and what I don’t know is whether it makes more economic sense to PW or their customers to design and deploy new blades vs the alternative of going through existing part stores as necessary when blades fail the requisite inspections, while developing new service limits based on the service lives of the blades which do fail inspection. That would depend on the remaining lifespan of these engines and whether they’re being actively manufactured and sold or just maintained for a shrinking fleet of aircraft which are equipped with them. The design changes necessary are only part of the process, you have to design and test the manufacturing process of the new blades, do destructive testing of the new blades, certify the new blades, and finally phase out the old blades, which may involve scrapping millions of dollars worth of inventory.