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Asiana flight crash at San Francisco

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Asiana flight crash at San Francisco

Old 9th Jul 2013, 19:51
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Ifs and buts about visual approach maybe, but they were 650ft from the threshold, and 0.25nm from touchdown zone, I think a low hour PPL student would pick that up!
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Old 9th Jul 2013, 19:53
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I don't think this has been posted here before..

Stories of bravery emerge from Asiana Airlines crash | World news | guardian.co.uk

Aircraft crew and emergency first responders have revealed they used knives, an axe and sheer muscle to free people trapped in the burning Boeing 777 that crashed at San Francisco airport.

The dramatic accounts on Monday helped to explain how 305 of the 307 people on board Asiana Airlines flight 214 survived when it smashed on to the runway on Saturday.

As smoke and fire engulfed the wreck pilots and attendants used knives to slice off seatbelts that tangled passengers. At least one knife came from in-flight cutlery; others were lobbed in by police officers on the runway.

A pilot used a cockpit "crash axe" to deflate an evacuation slide that had inflated inwards, pinning a colleague. Another pilot carried a wounded passenger to safety as jet fuel spurted.....

...snip....

The fire crew were astonished to discover a police officer, Jim Cunningham, inside the plane helping the evacuation without protective gear. He and a colleague had been among the first at the scene. After throwing knives to crew members aboard he went in himself. "I didn't think about it. I just knew people were trapped in there. I just thought, 'I'm kind of a tough guy, I can hold my breath if there's a lot of smoke,'" Cunningham said.
If I remember correctly 47 people have serious injuries which I think usually means broken limbs or worse, so I'm not surprised some people didn't run very far after they went down the slides.

Last edited by cwatters; 9th Jul 2013 at 19:57.
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Old 9th Jul 2013, 20:13
  #1223 (permalink)  
 
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Pitch

Looking at the bystander footage of the incident does anyone observe the pitch to be above normal. Clearly an early excessive nose up would exacerbate the loss of airspeed and increase AOA. Hard to tell given camera angles and distance. Before availablity of the bystander video it was already suggested that the tail strike was an indication of high pitch.

Very impressed at the structural strength of the a/c and the new improved fire retardent materials. Manufacturer did a superb job with this a/c.
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Old 9th Jul 2013, 20:20
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Maybe I'm just tired, and I'm fully ready to be lambasted, but the graphic in post #1210 seems way off to me. I've plotted the NTSB data (using red) on the same scale. Am I missing something?
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Old 9th Jul 2013, 20:23
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Originally Posted by Jazz Hands
Maybe I'm just tired, and I'm fully ready to be lambasted, but the graphic in post #1210 seems way off to me. I've plotted the NTSB data (using red) on the same scale. Am I missing something?
That graphic in post 1210 was created using radar return data from FlightAware, and it's taken in one minute intervals. It's unlikely to be nearly as accurate as ADS-B tracks or DFDR.
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Old 9th Jul 2013, 20:27
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Mic Dundee
great post
Thank you
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Old 9th Jul 2013, 20:28
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Mic, a very enlightening if sad post. I find it balanced and well written. I just hope someone takes heed and actually start letting pilots fly rather than just be systems managers. I know it's difficult to change cultures so entrenched but this accident seems to have been waiting to happen. Frankly fare paying pax deserve much better.
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Old 9th Jul 2013, 20:31
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That graphic in post 1210 was created using radar return data from FlightAware, and it's taken in one minute intervals
Can't claim I know how it was sourced, but it looks more frequent than one-minute intervals. Very misleading, too, especially the bit about the rapid drop.
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Old 9th Jul 2013, 20:33
  #1229 (permalink)  
 
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DWS


Is there or is there NOT an AOA indication on 777 either measured or computer derived ?
We don't have it on our fairly sizeable fleet - I suspect it might be a customer option.

Last edited by wiggy; 9th Jul 2013 at 20:35.
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Old 9th Jul 2013, 20:33
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Looking at the bystander footage of the incident does anyone observe the pitch to be above normal.
It certainly seems that way. For a stable flap 30 landing, the attitude should be close to zero degrees relative to the horizontal, so about the same as if it were sat on the ground. Anything higher than that and the speed is slower than it should be (unless it was going-around but we know that didn't happen).
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Old 9th Jul 2013, 20:36
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Very misleading, too, especially the bit about the rapid drop.
Quite so, in fact the NTSB in today's briefing specifically stated that the stories circulating about a sudden increase in ROD on final approach were erroneous.
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Old 9th Jul 2013, 20:42
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When the airspeed drops to top of yellow band, or lower, an aural "airspeed low" warning is generated. At least in our fleet.
As the aircraft was high on the glide slope one possible scenario that would make sense as to why the aircraft stalled is if the crew dialed the altitude in the altitude select window on the mode control panel down and then hit FLCH to keep the thrust levers at idle. The problem with this technique is that the pitch envelope protection will not protect you if your airspeed decreases below minimum maneuvering speed(which it did in this accident). You would get the AIRSPEED LOW EICAS MESSAGE but no speed protection from the autothrottle system. One can only imagine the confusion in the cockpit as they approached the water and the thrust levers were at idle, then raise the nose to try and stretch the glide, and then at the last minute manually advancing the thrust levers. This "gotcha" referred to in posts 1209 and 1210 is a NOTE in the Boeing Systems Manual in the flight controls section under envelope protection. If they were on speed when they raised the nose they had approximately 30 knots before the aircraft would have stalled.

Last edited by Keylime; 9th Jul 2013 at 20:47.
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Old 9th Jul 2013, 20:55
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Having seen the amateur video taken from a distance, I can see the logic of the NTSB response, however, they published data which appears to show that he was at or below stall-speed and accelerating the engines hence pitch-up. In my mind he was in the too-low energy corner. How he got there is for someone else to admit.
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Old 9th Jul 2013, 20:57
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What I don't understand, assuming they had A/T disconnected, is why the wake up function didn't occur when A/S decayed below VLS. Further, why no crew reaction to the AIRSPEED LOW EICAS. Is it possible the crew disengaged the A/T using the ARM switches???!!! 😳😳
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Old 9th Jul 2013, 20:58
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briefing streaming link

Originally Posted by Squawk ident
San Francisco –The National Transportation Safety Board will hold its third media briefing today on the investigation into the crash of Asiana Airlines Flight 214, in San Francisco, that occurred on May 6, 2013.

Event: Press Briefing

Date/Time: Tuesday, July 9, 2013 at 2:00 p.m. (PDT)
CNN is currently showing the briefing room and a "starting soon" label at this one of their streaming channels:
CNN streaming video for 7/9 briefing
They subject you to a 15-second or 40-second advertisement first.
At two minutes to the hour this is showing live video of the briefing room, with people milling about doing setup checks or the like. Yesterday's briefing started late.
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Old 9th Jul 2013, 20:58
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This is the part that gets me, each time I read it. I've seen various versions of this in this thread, and it makes me uncomfortable.
One can only imagine the confusion in the cockpit as they approached the water and the thrust levers were at idle, then raise the nose to try and stretch the glide, and then at the last minute manually advancing the thrust levers.
The bolded part is what I don't "get."

I was taught that you use power to stay on (or addjust to) glide slope, pitch to stay on (or adkust for) airspeed when making an approach to land. (Of course, the two work together to give you the performance you are trying to achieve. )

I was also taught that if you are low/slow on approach to landing, pulling the nose up "to get to the runway" makes your problems worse if that is all you do.

If automation and its helpful features has taught (inadvertently?) many pilots now current in various aircraft that you fly the plane by using one hand (stick), then it's a wonder more planes don't crash more often.

Last edited by Lonewolf_50; 9th Jul 2013 at 21:00.
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Old 9th Jul 2013, 20:59
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Originally Posted by Jazz Hands
Can't claim I know how it was sourced, but it looks more frequent than one-minute intervals. Very misleading, too, especially the bit about the rapid drop.
My mistake about one-minute intervals. I had previously thought the most granular information one could get from FlightAware was one-minute intervals but I was mistaken.

Here's the original source of that graphic:

http://www.nytimes.com/interactive/2...nt.html?ref=us

Here's the FlightAware data:

Flight Track Log ? AAR214 ? 06-Jul-2013 ? RKSI / ICN - KSFO ? FlightAware

Interestingly, there's no breakdown in "seconds"... it's assumed by whoever assembled the graphic, that if there are 5 track points at 2:27, they're equally spaced and likely 12 seconds apart each. I would guess that's a dangerous assumption.
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Old 9th Jul 2013, 21:02
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Has anyone heard or noticed if the final approach was to the original runway designated, and/or ATC changed designated runway for final?

Edit: In reference to the descent profile, I would not use flight aware data. This may or may not be from other ADSB sources.

Last edited by UAVop; 9th Jul 2013 at 21:06.
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Old 9th Jul 2013, 21:07
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Am I right in thinking that the most commonly-quoted reasons for retention of pilots, despite advances in automation, are that only a human can think flexibly enough to react to any unforeseen circumstance, and that only a human can continue to fly the aircraft when critical elements of automation fail? If I'm right then it follows that a pilot must have as his/her sine qua non the ability to fly (and land) the aeroplane with degraded systems, possibly in poor weather, possibly with no availability of external navigation aids, possibly with communication failures, etc etc. If these are not the first and foremost requirements, then why retain pilots at all? If 'lack of ILS' or 'elected to fly a visual approach' are even cited as contributory factors in this accident, is the piloting profession moving itself a step closer to oblivion? The human beings at the front end have to be capable of safely hand-flying the aircraft with the minimum of external assistance, which implies training and then regular proper practice (not just taking manual control of a stabilised approach on short finals) , or they will in time come to be viewed as surplus to requirements.

Last edited by Easy Street; 9th Jul 2013 at 21:09.
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Old 9th Jul 2013, 21:21
  #1240 (permalink)  
 
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The A/T servo on 777 is considerably lighter than that of 747 and 737, if you happen to rest your hand on it during idle operation, the servo can have a hard time erecting the lever back up.
The throttles on all Boeing North airplanes have the same force requirements to move - about 2.5 lbs force at the knob. In fact, with the exception of the 787, they all use minor variations on the same friction device for throttle 'feel'. Naturally, the 747 requires twice the force to move all the throttles since it has twice as many throttles to move. The autothrottle servo has plenty of force margin to move the throttles, its the friction devices that slip - as designed - to allow manual override of the A/T. The throttle quadrant on the 747-8 is unchanged from the 747-400.

That's roughly half the force that was required on the pre-FADEC throttle cabled engines - typically about 4.5 lbs at the knob (sometimes as high as 6 lbs.).

Boeing airplanes automatically select 'approach' idle when flaps are 25 or greater. By regulation, it must take less than 8 seconds to go from approach idle to 95% of max GA thrust (in actuality it's more like 5-6 seconds). I'm not a pilot, but I've been in the flight deck for a number of flight test go-around maneuvers (typically selected at 250 AGL) - 744, 748, 757, 767, and 777. I've never seen us lose more than 50 ft after TOGA was selected. The flight test airplanes are typically pretty light, but Asiana would have been fairly light since they'd burned most of the fuel on a 10 hr flight.
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