You can’t copyright a title.
In other bad news for Boeing and/or Alaska Airlines: https://www.cnn.com/2024/03/22/business/alaska-airlines-fbi-passengers-crime-victims/index.html
As to Windrunner / Bladerunner, there are lots of ways to nearly bankrupt a billlionaire on the way to creating an outsized jet transport. Scaled Composites Stratolaunch - Wikipedia.
When I started in the industry that was referred to as “changing into your wetsuit.” Which generally meant swapping your uniform shirt for a patterned sportshirt or later polo, and ensuring your badge was in your suitcase, not around your neck.
The cultural norms and procedural requirements around post-duty drinking have only gotten more conservative and drier over the years. Which is frankly all to the good.
Yup. A possibility to be considered on every landing.
That’s the shortest runway at DFW, “just” 8500 feet long. Had they landed on either of the other two most common arrival runways that are 13,400 feet long they’d almost certainly have stopped on the runway. Sometimes silly-long is just right.
If the brakes operated normally for taxi-out, and perhaps for multiple flights since the repair 4 days ago, that suggests some of the “misassembly” was stuff inadequately torqued or safetied that finally spontaneously disassembled itself during that flight.
There are various flex lines between the upper and lower gear leg to absorb suspension travel, and also between the upper gear leg and the wing structure to absorb the motion of extension / retraction. Which lines should get a decent looking at by the preflighting pilot. A loose connection that wasn’t yet weeping would look about like a normal connection. So maybe not much to see.
My first thought was how did they get to the runway to take off if they didn’t have brakes?
Whivh is why I suspect spontaneous disassembly in cruise. It fell apart good!
I really am curious why the brakes worked on takeoff and not landing. Is there a massive pressure storage system? Did the hydraulic lines come apart in mid-air/
I’m speculating that a connection came undone in flight. By design, brake leaks will not deplete the hydraulic systems. But a brake leak can render a particular wheel brakeless.
I struggle a bit to understand how all 4 came apart on the same flight. There are some plumbing areas in common between the two wheels / brakes on a single gear leg, but there’s nothing within the hydraulic part of the brake system common to both gear legs.
Once we’re talking about an assembly error, damn near anything is possible. Maybe they’d somehow left one wheel brake completely disabled on each gear leg, and the other put together barely finger tight. Which connections held pressure for part of this flight, then parted.
Not much braking is used during taxi-out and successful takeoff, so the absence of half your braking power from the git-go might be totally invisible to the pilots. For sure you’d immediately notice if one whole side was brakeless, but you probably wouldn’t notice one wheel on each side being brakeless.
We know the improper work had been done 4 days previously. We don’t have any info that I’ve seen on whether the airplane had flown at all, or how much, between the work and the failure.
Switching gears ...
The problem might be electrical, not hydraulic. If somehow the antiskid system went stupid and decided all the wheels were locked when they were not, that might manifest as “no usable braking effort”. But I would sure expect that concern to be designed out of the system. But again once we have an assembly error any connector could have been left unplugged, or plugged in wrongly or whatever.
My bottom line: Mostly useless to speculate as the possibilities are many and there's no data available to us to reduce the field. Eventually somebody will know what really happened. And they may share it with the public.
I’ve always liked the folding wings on WWII Grumman aircraft (F4F, F6F, Avenger). They fold 90º along their longitudinal axis (i.e., along the span), and 90º backward – sort of like leaning an 8x4 sheet of plywood against your house. But how is it done? My 1/32 scale F6F Hellcat used a T-hinge. The wing ‘flapped’ on the ‘T’ part, and rotated (the spanwise movement) on the T’s shaft. I knew it didn’t work that way on real airplanes.
On a real airplane, the folding hinge is inclined aft (at the top), and in (at the bottom). I’m only guessing, but I think the angles are 45º because the wing needs to make two 90º turns. IANA engineer. Anyway…
Here’s a picture of the hinge on an F6F Hellcat.
Here’s a video of the wings folding on an Avenger.
Useless but fun. I didn’t think of the antilock system getting confused.
Thanks for the links. I always liked the folding wing but for some reason thought it was a 2 step event and not a single hing at an angle.
I was always confused as to what was going on in Cessna Cardinal RGs, 337s, etc. It’s the same idea with the hinge on the Grumman wings, but in my observations the landing gear drooped down before they began moving aft. I had to ask a (then-)GQ question about it. The ‘drooping’ is just the gear unlocking.
It’s a cool design, but I always figured the pre-flight checklist looked something like
F-8 Crusader takes off with the wings folded.
The video has at least two incidents involving F-8 Crusaders. (I fast-forwarded a bit.) While they showed pictures of a Phantom, I didn’t hear them talk about it.
An F-4 Phantom flew with folded wings, and I’m pretty sure there was at least one incident with a WWII era fighter that successfully took off and landed (by accident) with folded wings. But maybe I’m misremembering that.
Also, an F-15 lost an entire wing pnce and sucessfully flew bck and landed using one wing and fuselage lift. And, I’m guessing a LOT of rudder trim.
The Boeing 777-9 will have folding wings. Really.
The last ~12 feet of each wing will fold vertically on the ground looking like a giant winglet. That keeps the total span narrow enough that it’ll fit into current 777-sized parking spaces.
They’ll have to prove it can fly with them folded or do something pretty magic to prevent that. For reasons of taxi clearance, lowering the wingtips to the flight position has to be done just prior to taking the runway; not earlier.
Here’s a pretty good article w pictures.
Bigger picture …
Over the decades I’ve been doing this stuff TPTB have moved flap deployment ever earlier in the departure flow precisely to minimize the chance of last-minute hurry-up forgetfulness and maximize the number of built-in opportunities to double and triple check that flaps are deployed. As of when I retired it seems industry standard for setting takeoff flaps is right after engine start and before taxi. When I started in the biz it was normally about halfway to the runway or shortly after starting the last engine, since we routinely taxied on less than all of them.
Anyhow, they’ll have to delay 777 wing unfolding to just before takeoff, the polar opposite of the practice with their flaps.
Gonna be interesting to see how that works out.
The hinge line is 45 degrees both to the length of the wing, and 45 degrees to the length of the fuselage. This makes a 90 turn of the hinge move the wing in both directions.
That’s what I assumed, but IANA engineer, so I was just guessing. Thanks for the confirmation.
And if the first, then give a real good explanation of how you handle things if one is folded.
An interesting thing about the Crusader was the entire wing pivoted up to change the angle of attack to give it more lift. You can see it in the video. There’s a gap behind the cockpit when it’s tilted up.
Angle of incidence of the wing, which in turn affects AoA.
The Special Conditions for the folding wings are published (scroll to the bottom, though the rest is interesting too, at least to me!).
There are 10 conditions but some are an enormous amount of work to design and develop appropriate compliance demonstrations.