Asiana 777 hull loss at SFO

[albatross710]

The NTSB has just held another press conference, two interesting facts, they are interviewing all four flight deck crew including the check captain, and impact was at 106kts, up from the lowest speed of 103kts during the approach. Target speed was 137kts.

My understanding from various observations is that the aircraft was at a high nose up attitude which would be consistent with trying to maintain altitude at the slowing airspeed. The sort of thing that flight instructors teach us to intentionally do until eventually the aircraft stalls. So with this high AOA the aircraft was heading for a stall unless it had some help from the engines.

The 106 knt speed still appears to be below the stalling speed according to this reference. With the high angle of AOA the speed and resulting lift would have been disappearing very quickly.

Looking at the flight path comparison posted by vec earlier in the thread the aircraft was initially high on approach, requiring less power to intercept the approach, then it comes out of the steeper descent before sinking towards the runway.

Nothing new with this information, I guess the investigators need to determine the reason the required power was not forthcoming from the engines whether by command or other issue.

I heard mention that the throttles were at idle. I wonder if it would have been a help to increase the throttle prior to making the radio call for a go around. Something about aviate, navigate, communicate.

Whatever is the case, no doubt their will be multiple contributing factors which led to this situation.

Cheers

Alby

 

[oz_mark]

Looking at the flight path comparison posted by vec earlier in the thread the aircraft was initially high on approach, requiring less power to intercept the approach, then it comes out of the steeper descent before sinking towards the runway.

There are some charts around of the previous weeks approaches which suggests the previous days low approach was the more unusual approach.

 

[moa999]

Looking at the flight path comparison posted by vec earlier in the thread the aircraft was initially high on approach, requiring less power to intercept the approach, then it comes out of the steeper descent before sinking towards the runway.

As Ozmark mentioned.
Was a regular flight path on July 6, at least up until the last few minutes.


Sourced from Dailymail - San Francisco plane crash: Two dead after tail snaps off Boeing 777 | Mail Online

 

[Berlin]

Interesting article here on Germany's news magazine "Der Spiegel" which thankfully is available in English translation: Pilots: Missing Control Systems Led to San Francisco Crash - SPIEGEL ONLINE

According to this article, the difficult situation in San Francisco has been pretty much known for quite a while which even more poses the question why they put a pilot in charge who has hardly flown this type of aircraft at all. Maybe it's naive to expect this, but I'd rather have someone with a bit more experience in control if another airline even gives out special instructions about this particular port. If it had been Air France, we'd all be saying "Well, them again!" so this indeed doesn't shed the best light on Asiana, does it?

"Lufthansa statistics rank the San Francisco International Airport at the top of the list for aborted landings, which is why even before the Asiana crash landing, the German national carrier had implemented special safety instructions for ending flights there."

 

[docjames]

"Lufthansa statistics rank the San Francisco International Airport at the top of the list for aborted landings, which is why even before the Asiana crash landing, the German national carrier had implemented special safety instructions for ending flights there."

I wonder what % of these "aborted landings" relate to the significant Fog at SFO on a regular basis, and how applicable this statistic really is to the day in question (good visibility)?

I don't dispute that a steeper than usual descent profile is an issue however.

 

[moa999]

Interesting SMH article based on interviews/press conference with cabin attendants.

San Franciso Plane Crash Asiana Cabin Manager Reveals What Happened

At least not all passengers took luggage - many without clothes, mobiles, money and passports.

 

[markis10]

As Ozmark mentioned.
Was a regular flight path on July 6, at least up until the last few minutes.

View attachment 16970
Sourced from Dailymail - San Francisco plane crash: Two dead after tail snaps off Boeing 777 | Mail Online

That slide is irrelevant as it shows the profile for too longer time, you need to look at the last few minutes or when the aircraft is on final where it goes wrong, for instance here is a plot with a UA flight (black) vs Asiana (Red) on the same day:

The UA aircraft was on a 3.2 degree glide path pretty much all the way, the energy height graph is also interesting:

Note both these have been sourced from Flightaware and published here: http://flyingprofessors.net/what-happened-to-asiana-airlines-flight-214-2/
(generally ADSB based data), no doubt the final NTSB report will be more authoritative using the black box datum

 

[blackcat20]

There are some charts around of the previous weeks approaches which suggests the previous days low approach was the more unusual approach.

I'm sure I read somewhere that the previous days approach had a go-around, hence the weird approach.

 

[moa999]

Interesting article here on Germany's news magazine "Der Spiegel" which thankfully is available in English translation: Pilots: Missing Control Systems Led to San Francisco Crash - SPIEGEL ONLINE

Spiegel article also seems to list as contributing factors the glideslope being out of action and the typical "slam dunk" approach at SFO (equating it as an attempt to reduce noise -- which I find weird given in this runway config the plane was landing from the sea, albeit at SFO it is more the Bay.)

 

[markis10]

Spiegel article also seems to list as contributing factors the glideslope being out of action and the typical "slam dunk" approach at SFO (equating it as an attempt to reduce noise -- which I find weird given in this runway config the plane was landing from the sea, albeit at SFO it is more the Bay.)

I am not sure they were that contributing given it was VMC and the PAPI would have been active until it got taken out:


07/046 (A1326/13) - RWY 28L PAPI U/S. 06 JUL 22:19 2013 UNTIL UFN. CREATED: 06 JUL 22:19 2013

07/045 (A1324/13) - AD AIRPORT CLSD. 06 JUL 20:10 2013 UNTIL UFN. CREATED: 06 JUL 20:10 2013 (cancelled at 23:09Z)

 

[Berlin]

the typical "slam dunk" approach at SFO

Can any one of the more technical minded people here comment on this as I had never heard this expression. Is this a fairly common thing and should it cause any issues for an experienced pilot? Are there other airports "notorious" for this kind of approach?

 

[albatross710]

Note both these have been sourced from Flightaware and published here: http://flyingprofessors.net/what-happened-to-asiana-airlines-flight-214-2/
(generally ADSB based data), no doubt the final NTSB report will be more authoritative using the black box datum

Thanks for republishing these charts. My reading is that the aircraft was moving towards this outcome from 2+ miles from touchdown.

 

[markis10]

Thanks for republishing these charts. My reading is that the aircraft was moving towards this outcome from 2+ miles from touchdown.

'

Correlated to reported transcripts I suspect the cross over at 2 miles was probably where a go around should have been discussed and power applied, thats around 53 seconds out based on reported airspeed correlating to roughly similar ground speed.

 

[albatross710]

'

Correlated to reported transcripts I suspect the cross over at 2 miles was probably where a go around should have been discussed and power applied, thats around 53 seconds out based on reported airspeed correlating to roughly similar ground speed.

I'm sure there are better transcripts around of the ATC conversation but listening to this ATC conversation it sounds like the pilot had requested emergency vehicle response before the ground contact or is it a standard broadcast by the tower to advise what was happening?

 

[markis10]

I'm sure there are better transcripts around of the ATC conversation but listening to this ATC conversation it sounds like the pilot had requested emergency vehicle response before the ground contact or is it a standard broadcast by the tower to advise what was happening?

Its a little odd, the moment something goes wrong the tower will hit the crash alarm which activates the first responders, in the meantime they need to deal with traffic that no longer have a runway available.

 

[albatross710]

Its a little odd, the moment something goes wrong the tower will hit the crash alarm which activates the first responders, in the meantime they need to deal with traffic that no longer have a runway available.

Is there a transcript of what the pilot may have said in his broadcast. I couldn't make it out from that recording ie did the pilot's call trigger the emergency response or did the controller initiate the crash alarm in response to his visual observation.

 

[Foreigner]

So was the pilot with 43 hours on the B777 pilot in command?

 

[markis10]

Is there a transcript of what the pilot may have said in his broadcast. I couldn't make it out from that recording ie did the pilot's call trigger the emergency response or did the controller initiate the crash alarm in response to his visual observation.

ATC would have triggered the response before the pilot.

 

[Boris spatsky]

So was the pilot with 43 hours on the B777 pilot in command?

Not confirmed, but i don't think so based on the evidence.

 

[markis10]

Good comment piece:

A pilot's perspective on the Asiana crash | Asiana crash | SBS World News