Quote:
Originally Posted by onewhippedpuppy
I would defer to Jeff as the expert, but to me it looks like the landing gear was pushed vertically upwards through the upper skin of the wing. You can see where the skin was pushed upwards in a u-shape just above the gear. Which is also why the airplane is leaning sideways at rest.
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That's what I think I see as well. The landing gear is pushed up through the upper wing skin. Looks bad, but it's certainly not terminal. We replace wing skins all the time.
I wish I still had a way to follow this kind of incident as first the survey, then then the proposal, then the repair proceeds, or not. I did not personally work on single aisle (737, 757) aircraft, just the twin aisle (747, 767, 777, and 787), but I knew everyone who did. Alas, everyone I worked with have now either retired or have left AOG, so I've since lost my connections.
I bet, however, that this one gets repaired. I would not be surprised if the front, main, and rear spars are o.k., along with the landing gear beam (a short section that looks like a spar that runs perpendicular to the center bulkhead and out to the rear spar, where the aft pivot trunnion mounts). If any of the wing spars were substantially damaged, it might be a write-off, but I doubt they were. The landing gear beam is replaceable, with some difficulty, but it is replaceable.
On a related note, that aft pivot trunnion is a wear item, like suspension bushings in our cars. The front pivot trunnion rides in a floating needle bearing, where the aft rides in a solid bronze bushing. The front floats to help alignment, the aft takes the "big hit" on landing, so it kind of has to be a bit more robust, hence the solid bronze bushing.
That landing gear beam has to be removed to enable replacement of that bushing. No small amount of work, as can be imagined. Once removed, the old bushing has to be pressed out, then the hole in the beam machined to a depth that removes all corrosion (water gets in there once the bushing gets loose in the hole). A new bushing is then pressed in and bored to its finished size. This is all done on a hydraulic press and a vertical mill. "Installation is reverse of removal."
Well, what if we didn't have to remove that landing gear beam? What if we could press the old bushing out with the beam still in the wing? Then machine the hole, press in a new bushing, and machine the bushing to final dimensions all the while maintaining precise alignment with the forward needle bearing?
The tooling to perform those tasks in situ in the wing on the 777, without removing the landing gear beam, was one of the last designs I released. It saves hundreds of hours and days of downtime on the repair. I flew to a location in the Middle East to assist in its first use with one of our bigger customers. It worked pretty good, actually. They were thrilled.