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Friday, July 26. 2013
The evolving mystery of Flight 345
I'm sure we're all grateful to hear that crashing upon landing is "not in accordance" with Southwest's usual procedures.
So, this raises a damn good question. How does the nose of a modern jetliner drop five degrees in four seconds? Pilot sneezed and accidentally pushed the steering wheel all the way forward? These things are so big and clumsy that I'm not sure even that would do it in a mere four seconds.
Here's the footage from nearby:
Must have been a real case of 'mixed emotions' for the Southwest passengers. "Oh, no, the plane's having a dire problem — but at least we're on the ground!"
Still, from a by-the-book 2-degree up angle to minus-3 degrees down angle in a mere four seconds is a real poser. I'll post an update if & when we hear word from the NTSB.
Posted by Dr. Mercury in Hot News & Misc. Short Subjects at 14:45 | Comments (21) | Trackbacks (0)
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Wow! I love these airline disaster posts, Doc. I look forward to hearing what they can figure out about this one.
I love 'em too, Doc. The link 'Asiana' goes to was the most interesting piece I'd read in months. Or seen in months, given the great video clips. This crash is now looking seriously interesting. If we assume the pilot didn't sneeze, then doesn't it have to be mechanical error?
Well, it depends on whether or not we're ruling out "Hand of Fate", "Divine Intervention" and "Kismet meets Destiny". Assuming so, then one guess would be mechanical error, although I don't recall "Hard nose down!" being part of the electronic landing commands. They're usually much more fussy about such things when five seconds from touchdown.
The obvious culprit would be a stall, but I haven't read a hint about it going too slow, unlike Asiana. My best guess at this point, assuming something didn't actually break, is that the flaps or vertical stabilizer trim weren't in the proper position and they thought they had more lift than they did. That is, it stalled, but not at stall speed. It's to note that there are (at least) two episodes in 'Mayday' where an incorrect flap or trim setting was all it took.
Hmm, pilot error, mech probs.... Since we're playing idle speculation at this point and I'm at least as ignorant as anyone else, howzabout a little air anomaly - or weather, if you prefer. Micro-downburst or maybe a bit of someone else's vortex?
And speaking of the Asiana mess, I still want to hear from the NTSB intern who answered the TV station's fact-checking call. I'd bet 100 quatloos that he thought he was being punked (those names? are you kidding?) and told them, "Yeah, sure. click" just to make them go away
Well, it strikes me that a microburst or vortex wouldn't affect just the tip end of the plane like that, but you can bet it's in the running. They ran into a microburst 'wall', so to speak.
As for Asiana, I'll have some updates at the end of next week when I take over the morning links for a few days, although I haven't heard anything on the 'intern'.
I couldn't tell squat from either vid; both were nose down and sparking and no lead-in.
My bet would be that he was a little fast and high on the flare and the aircraft started to float in ground effect (the effect of proximity to the ground causing an increase in lift). The correct response if you have enough runway is to maintain the nose-up attitude until the speed bleeds off and the aircraft settles to the runway, or if you don't have enough runway add power and go around. There is, however, a strong urge to "force it" by lowing the nose and "planting" it on the runway. Doing that can result in "wheelbarrowing" like what happened here. As always, I reserve judgement awaiting more information.
That would be "...lowering the nose..."
I shall now go write "Preview is your friend" 100 times.
I take it you're using Chrome or Opera? Weirdo. But we still love you! Maggie's is open to all walks of life.
Both Firefox and IE now have built-in spell-checkers. This means you now have no more excuses not to join the 21st century. Sorry, I know it's a cold, hard truth for the Chrome or Opera lover to hear, but given how many pixels you wasted with your correction, and given how every additional pixel creates more server use and thus more heat and thus more cooling and thus more energy, it strikes me you'd at least want to use FF or IE to help save the planet.
Unless you want it to die, of course.
The choice is yours.
With all due respect Doc, lowing appears to be in the Firefox speller, and I suspect IE too (which I never touch unless I'm wearing rubber gloves). So a speller wouldn't have caught his error. By the way, Lowing is what cows do at eventide, so I'm sure it's in the MF lexicon.
Actually, what impresses me is that your spell-checker had eventide in it. :)
Yes, I knew that wasn't a good example, but hey, he's an Opera or Chrome guy. What's he know about cows?
#184.108.40.206.1 Dr. Mercury on 2013-07-26 21:00 (Reply)
I use the Speller for Dummies add-on. It has a lot of
Auld Anguish words in its dictionary.
#220.127.116.11.1.1 BillH on 2013-07-27 14:15 (Reply)
I could agree with every bit of that except for the "four seconds" part. These birds are really sluggish at low speeds, so it's hard to believe a mere 'overadjustment' would cause it to react so violently in just four seconds. This incident sure went from "no brainer" to "no answer" quickly.
Count out 4 seconds to yourself. It's longer than you think and 5 degrees is really not a lot of angle.
There's some details here (airspeeds, flap settings, etc) from people who seem to be knowledgeable.
I, myself, fly only as a passenger, and have been through LGA hundreds of times, with several hard landings. I have also heard some pilots list LGA among their least favorite airports due to (1) congested airspace, (2) tight, crooked approaches, (3) relatively short runways, and (4) sloping runways that are either coming up to meet you (runways 13 & 22) or falling away from you (runways 31 & 4 - I believe runway 4 was the runway for SWA345).
The weight of the plane would be on the wings, not the nose gear, even if it hit nose gear first, which doesn't seem likely geometrically.
Bouncing hard off the nose gear tends to crumple the fuselage, say trying to pin the plane on the ground after a bounce off the main gear, but the nose gear doesn't collapse from that.
More likely a nose gear failure, say it didn't lock, made visible by a hard landing.
Probably porpoising if it wasn't mechanical. (5000+ hrs four-engine recip)
Did you gentlemen give up on the idea that it was a tire blow out?
The question isn't what happened to the front gear, but why the plane was nose-down when it should have been flared. If the animation's correct, that's a pretty amazing drop in attitude in a mere four seconds. As I said in the post, I'm not sure an airliner would do that in four quick seconds even if the pilot jammed the stick to the firewall.
The cockpit voice recorder was supposedly going to be analyzed yesterday, so we might see some additional info soon.