Asiana 777 at SFO

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Asiana 777 at SFO

Postby reubee » Sat Jul 06, 2013 9:22 pm

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Re: Asiana 777 at SFO

Postby monchavo » Sat Jul 06, 2013 10:42 pm


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Re: Asiana 777 at SFO

Postby monchavo » Sat Jul 06, 2013 10:47 pm

One comment strikes me as interesting - the burn pattern visible from above.
I wonder if footage of the whole event will come to light later, I'd be interested to see the motions of the bird leading to the tail separation.

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Re: Asiana 777 at SFO

Postby Sickbag » Sat Jul 06, 2013 11:14 pm

TRUMP: in-presidency structural break-up
within 18 months...

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Re: Asiana 777 at SFO

Postby monchavo » Sun Jul 07, 2013 2:14 am


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Re: Asiana 777 at SFO

Postby Verbal » Sun Jul 07, 2013 5:53 am

I blame the Koreans.
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Re: Asiana 777 at SFO

Postby reubee » Sun Jul 07, 2013 8:18 am

I blame the Koreans.
Says the Boeing engineer whose avatar is a Boeing short of the runway! But you will probably be proven correct.
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Re: Asiana 777 at SFO

Postby Procede » Sun Jul 07, 2013 8:57 am

An airport not providing any landing aids (glideslope or PAPI) will certainly be contributing...

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Re: Asiana 777 at SFO

Postby Chris Foss » Sun Jul 07, 2013 12:53 pm

Heavy tail strike suggests lack of airspeed.
Gear ripped off and slats/flaps fully deployed, so landing config looks ok.

Very similar to the BA 777 at LHR. I wonder if the cause was also similar?

Who needs landing aids when you are VFR with light winds into a long, well defined runway.

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Re: Asiana 777 at SFO

Postby Chris Foss » Sun Jul 07, 2013 1:02 pm

Another question is why they were right of the center line?

Debris field suggests slight angle to approach, as though they may have been originally lined up for 28R.

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Re: Asiana 777 at SFO

Postby Chris Foss » Sun Jul 07, 2013 2:42 pm

Last ATC exchange was final clearance to land 28L 40 seconds before impact. No indication of problem in pilot's voice or message.

BA38 (777 at LHR) also had similar ATC clearance exchange 32 seconds before impact with no indication of problem. The BA 777 managed to get a mayday out 10 seconds before impact and retract some flap to extend the glide.

Witnesses report plane wobbled on approach. Could be interpreted either as aerodynamic stall, control problems or controlled change of direction (cleared for 28L but might have been lined up for 28R?)
Other witness said that the plane flipped over on its back, so goes to show how unreliable witnesses are.

Passenger said that the plane 'flipped up and down' before impact. Passengers on BA38 didn't feel anything out of the ordinary before impact.

Looking at new photos, could be the right main gear that struck sea wall first explaining the debris field right of centre line. Also, the ground marks only start 80-120 feet from the aircraft suggesting that the aircraft was somehow airborne as it left the runway. A twitter pic shows one wing high and the fuselage at a high angle. This may have looked something like a cartwheel but it certainly wasn't sliding on the ground all the way from original gear or tail impact.

There is also interesting damage to the leading edge of the vertical stab. Could it be possible that the gear sheared off and struck the vertical stab leading to the disintegration of the rear empennage? Not sure. But looking at the fuselage section still attached to the vertical stab, the front edge looks like a failure under tensile load supporting the theory that the vertical stab was pulled back. With a tail strike, that section of fuselage would show compressive failure, i.e. buckling. Similarly, the end of the main fuselage just above the pressure bulkhead does not show compression or buckled edges at the top.
Nor do the ground marks show the classic signs of a tailstrike.

One might also expect to see buckling of the top fuselage just aft of the main wings in a tailstrike severe enough to rip the tail off.

Either way, he was way low on the GS. But I may have to retract the low airspeed theory.

Best guess is:
- Low on GS with right wing low
- Right main gear strikes sea wall
- Gear flips up and hits vertical stab
- Rear empennage breaks off/apart
- Aircraft starts to yaw right raising left wing
- Rapid deceleration
- Aircraft pancakes down and slides short distance to final position

Superb aircraft design holds together saving a lot of lives!

Main question is why he was low on GS.

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Re: Asiana 777 at SFO

Postby monchavo » Sun Jul 07, 2013 3:06 pm

Chris,

one of the passengers on board the plane described it as "cartwheeling". Agreed that spatial awareness might be difficult when you're inside with a tiny portal to look through, but it will be interesting to see what trajectory the bird took to earth.

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Re: Asiana 777 at SFO

Postby Chris Foss » Sun Jul 07, 2013 3:20 pm

Chris,

one of the passengers on board the plane described it as "cartwheeling". Agreed that spatial awareness might be difficult when you're inside with a tiny portal to look through, but it will be interesting to see what trajectory the bird took to earth.
Yes, both internal and external witnesses describe a cartwheel.

Also, the twitter pic ( https://twitter.com/stefanielaine/statu ... 96/photo/1 ) during the accident shows it in an unusual attitude, possible nose down left wing and rear fuselage high. Hard to tell as its not a good picture.
Right wing tip looks to have damage consistent with this.

More passenger witness account describe the stewardesses at the rear of the aircraft being ejected early on with up to five people coming to rest close to the tail debris.

11:26 37.5900 -122.3070 297° West 169 194 1,400-1,380 FlightAware
11:27 37.5988 -122.3270 299° West 145 167 800 -1,380 FlightAware
11:27 37.6016 -122.3340 297° West 141 162 600 -1,320 FlightAware
11:27 37.6045 -122.3410 298° West 134 154 400 -900 FlightAware
11:27 37.6073 -122.3480 297° West 123 142 300 -840 FlightAware
11:27 37.6103 -122.3550 298° West 109 125 100 -120 FlightAware
11:28 37.6170 -122.3740 294° West 85 98 200 120 FlightAware


Struggling with the airspeed data as it shows very low just prior or during crash, but this may be post - initial impact and just shows the deceleration during the 'cartwheel'. The data also shows the aircraft climbing for a brief moment which again could be the result of the aircraft rising and almost flipping over.

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Re: Asiana 777 at SFO

Postby 3WE » Sun Jul 07, 2013 7:31 pm

I also sometimes wonder about long haul, top of the line pilots who make ~2? landings/month after being trapped in the prison-cell cockpit for who knows how many red-eye hours/fubar'd sleep patterns, who might not be at the top of their mental game for a severe vmc approach.

Fixate on the runway and get low and slow, and then oh crap / old fashioned 727 with 50 degrees of flaps and slow-spooling jet engines?

....and yeah, the mysterious case of engines that won't power up...is this the second of this one-in-a-million occurence?/ice/fuel/...
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Re: Asiana 777 at SFO

Postby Chris Foss » Sun Jul 07, 2013 9:56 pm

I also sometimes wonder about long haul, top of the line pilots who make ~2? landings/month after being trapped in the prison-cell cockpit for who knows how many red-eye hours/fubar'd sleep patterns, who might not be at the top of their mental game for a severe vmc approach.

Fixate on the runway and get low and slow, and then oh crap / old fashioned 727 with 50 degrees of flaps and slow-spooling jet engines?

....and yeah, the mysterious case of engines that won't power up...is this the second of this one-in-a-million occurence?/ice/fuel/...
Been on the flight deck a few times at the end of long hauls and I can see your point.

Again, doubt this is a fuel starvation incident as 3 passengers all describe the engines powering up just before impact. That of course doesn't discount a slow spool up.
Consensus is that they were initially high on the GS so maybe as you say 3WE: a jaded reaction/over reaction.

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Re: Asiana 777 at SFO

Postby ocelot » Sun Jul 07, 2013 10:27 pm

Would the gear striking the tail be enough to wreck it so thoroughly? I know the MLG of a 777 is not exactly a small or light object, but it appears the entire tail section came off... Also, the gear was found in the water, so it didn't make it over the seawall; it seems unlikely that this would be the case if it had made a substantive collision with the rest of the airframe as that would have propelled it forward.

I was thinking that maybe the right engine also struck the seawall, and then came loose and struck the tail; that would definitely be large enough to cause the observed results. Problem with this is that it looks like the right engine came to rest along with the fuselage and it was the left engine that went flying.

Of course: it was the left side that struck, not the right. avherald says "the aircraft turned around counterclockwise by nearly 360 degrees" -- that means it most likely struck on its left side. I can't remember now if anyone's actually said it was the right gear that struck and was found in the water; I think not, and I think we've been assuming the right side struck because the strike was to the right of the runway centerline. Also, the left wing seems to have had a rougher ride: while the tip of the right wing is bent, the right wing's flaps are still attached and the left wing's flaps seem to have been left behind somewhere.

This suggests that the left gear and engine struck the seawall and that the engine collided with the tail, wrecking it and getting propelled further forward than it would otherwise go. But the physics of this doesn't entirely work out either.

I think it would be very interesting to find out for sure which engine is which and which gear is which.

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Re: Asiana 777 at SFO

Postby 3WE » Sun Jul 07, 2013 11:47 pm

I also wonder if there will be evidence of Oriental CRM with the captain flying and the inferior pilot is not wired to say, "Hey senior pilot and my superior officer, you are screwing the pooch, go around now or give me the airplane!"

(To be politically correct, it's happened a few cultures).
Last edited by 3WE on Mon Jul 08, 2013 12:00 am, edited 1 time in total.
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Re: Asiana 777 at SFO

Postby Chris Foss » Sun Jul 07, 2013 11:58 pm

Would the gear striking the tail be enough to wreck it so thoroughly? I know the MLG of a 777 is not exactly a small or light object, but it appears the entire tail section came off... Also, the gear was found in the water, so it didn't make it over the seawall; it seems unlikely that this would be the case if it had made a substantive collision with the rest of the airframe as that would have propelled it forward.

I was thinking that maybe the right engine also struck the seawall, and then came loose and struck the tail; that would definitely be large enough to cause the observed results. Problem with this is that it looks like the right engine came to rest along with the fuselage and it was the left engine that went flying.

Of course: it was the left side that struck, not the right. avherald says "the aircraft turned around counterclockwise by nearly 360 degrees" -- that means it most likely struck on its left side. I can't remember now if anyone's actually said it was the right gear that struck and was found in the water; I think not, and I think we've been assuming the right side struck because the strike was to the right of the runway centerline. Also, the left wing seems to have had a rougher ride: while the tip of the right wing is bent, the right wing's flaps are still attached and the left wing's flaps seem to have been left behind somewhere.

This suggests that the left gear and engine struck the seawall and that the engine collided with the tail, wrecking it and getting propelled further forward than it would otherwise go. But the physics of this doesn't entirely work out either.

I think it would be very interesting to find out for sure which engine is which and which gear is which.
There are some interesting hi-res shots of the sea wall, debris trail and final resting place of the aircraft. The ground marks here are very revealing and it looks like the nosewheel seemed to leave a telling black mark throughout.

I'm pretty sure the aircraft was close to wings level at first impact with runway surface as the fuselage and engines all left clear ground marks. Left engine seperated early and went off to the right of centreline while the aircraft went off to the left. Can't see the spotters video as my office IT has a block, but it may shed light on whether the aircraft did a flat 360. nose gear marks suggests it could have.

A fair number of cargo/baggage bins spread out close to the threshold, so while the tail detached aft of the pressure bulkhead, there must have been significant damage and breach of the lower hull very early on. Kinda rules out the gear taking the tail off theory which was pretty weak to start with.

More passenger statements saying they could see the runway behind and below them early on and people being ejected at first impact.

Like others, just in awe of the integrity of that aircraft and the amazing survivability rate, but still very sad that people died and were so badly injured.

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Re: Asiana 777 at SFO

Postby Chris Foss » Mon Jul 08, 2013 12:16 am

I also wonder if there will be evidence of Oriental CRM where the inferior pilot is not wired to say, "Hey senior pilot and my superior officer, you are screwing the pooch, go around now or give me the airplane!"

(To be politically correct, it's happened a few cultures).
Yup. Sorry to say that I have seen this in the majority of the 5000 flights I dispatched. I dislike generalisation, but western airlines are ahead in CRM. Even the mighty SQ had their buried issues in SQ006 out of Taipei. I had no problem gobbing off if I saw the CO putting the wrong data in his computer from my loadsheet and often saw the co pilot look at me like I'd just committed hari kiri. But I also saw some great pilots first hand and noteworthy exceptions in CRM.

Things are changing, never fast enough, but there will always be some degree of hero-worship/fear/lack of confidence on the CPs' part.

Who's to say: things may have developed too quickly and even a sharp CP may have made the call but fast reactions couldn't save the day.

Asianna have stated that there were no issues with the aircraft, again, not sure of the validity of that statement, but this and witness statements suggest it was not another BA38.

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Re: Asiana 777 at SFO

Postby Marc 1 » Mon Jul 08, 2013 12:44 am

Discuss - I'd say even more woeful performance by the crew than the 737 that landed short recently - at least they could 'blame' the rain for their stupidity. Asiana - don't let the work experience schoolboy fly the plane - it will end in tears.

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Re: Asiana 777 at SFO

Postby Ed » Mon Jul 08, 2013 2:42 am

Where are the freaky-ass plane spotters when you need then? When there is no crash, they are whacking each other off and snapping 30 frames per second at the perimeter fer chrissssakes.

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Re: Asiana 777 at SFO

Postby reubee » Mon Jul 08, 2013 2:43 am

Some good stuff out of the NTSB already http://www.youtube.com/watch?v=XLYeUbey ... e=youtu.be and on their twitter page https://twitter.com/NTSB. I thought your govt agencies had no money

And of course in this day of video, there was one who looks like he caught it on tape, http://www.youtube.com/results?search_q ... isco+crash
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Re: Asiana 777 at SFO

Postby NoFlyZone » Mon Jul 08, 2013 4:00 am

I Heard This Guy Only Had 43 Hours On The Plane!!!!!!!!!!!!!! What A Idiot!!!!!!!!!!!!!!!!!!!!!

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Re: Asiana 777 at SFO

Postby Peminu » Mon Jul 08, 2013 4:46 am

I believe that we will have a final report sooner than other accidents, because of the evidence, number of survivors and quick recovery of recorders.

No connection to London 777 crash:
1-engines not RR, but P&W, with different fuel feeding system.
2-recorders and survivors show an attempt yo accelerate engines prior to crash.

I heard during press conference of the NTSB that the PAPI was working on that runway. ILS wasn't.

So, my guess (c'mon, we need a lot of opinions and especulations to make this page go back to life) is that this pilots were very comfortable with the automatization of the airplane, and not used to land it manually, without the ILS. So, they noticed too late that they were short, low and slow, and could only try to increase power and raise the nose.

That problem happens when good pilots are removed from 777's and make them fly airbuses. Rookies cannot replace them.
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Re: Asiana 777 at SFO

Postby Gabriel » Mon Jul 08, 2013 5:07 am

I Heard This Guy Only Had 43 Hours On The Plane!!!!!!!!!!!!!! What A Idiot!!!!!!!!!!!!!!!!!!!!!
Well, at some point, every pilot had 43 hours in each type where they eventually accumulated 43 hours or more.


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