just now ~ 777 crash @ SFO

[billvon 2,400]

>The video looked to me like it showed a rooster tail in the water prior to impact with the land.

With an attempted goaround being initiated you'd see a pretty big roostertail both from the engine exhaust and the wingtip vortices interacting with the water - even if the plane wasn't actually in the water.

[skycatcher68 7]

JohnMitchell

If the stick shaker was going, they were at least approaching critical angle of attack, in other words, a stall.

It can be the hardest thing in the world for a pilot to put the nose down when he doesn't want to, as in a situation like this. But when you're literally behind the curve, in the zone of reverse command, you have to fight the urge to pull back. Many, many pilots have made that fatal mistake. I argue that if they had kept the plane more level and continued to add power, they would have avoided the tail strike and had fewer injuries.

Lowering the nose would have been the worst thing they could do, it only makes the aircraft descend faster.

Flying lesson number one: Give up airspeed for altitude or give up altitude for airspeed.

These pilots had to conserve altitude to clear the wall which meant giving up all the airspeed that they could until they had more engine power. They did everything much too late, but dropping the nose would have just killed scores more people.

They were already too low to clear the wall, there's no way to make a 777 do a Fosbury Flop to jump up to the runway.

What if the Bible had been written by Stephen King?

[airdvr 197]

Wouldn't a 777 have enough thrust to climb out of that once the engines spooled up?

Please don't dent the planet.

Destinations by Roxanne

[quade 3]

airdvr

Wouldn't a 777 have enough thrust to climb out of that once the engines spooled up?

Maybe. The issue is it takes a hell of a lot longer than most people would think to go from idle to full thrust in a turbojet. That's the reason you'd want to fly a stabilized approach in the first place, so you don't have to make drastic corrections.

quade -
The World's Most Boring Skydiver

[Ron 7]

Quote

Wouldn't a 777 have enough thrust to climb out of that once the engines spooled up?

1. The engines have to actually spool up. That takes a few moments then a few more from the start of the increase to full power - It takes a time from firewall to usable thrust.

2. You have to arrest the decent and reverse that trend. A 777 has an awful lot of mass to change direction.

Even at idle the engine produces some thrust... Enough to blow a little water around. At even partial power it is enough to make it "look" like it is making huge amounts of thrust, but that will not be enough to stop the decent and establish a climb.

"No free man shall ever be debarred the use of arms." -- Thomas Jefferson, Thomas Jefferson Papers, 334

[3mpire 0]

I read that the engines were at 50% thrust -- what would be considered idle for a 777?

[3mpire 0]

Quote

That's the reason you'd want to fly a stabilized approach in the first place, so you don't have to make drastic corrections.

I know that a stabilized approach is a constant glide angle and speed targeted at a point on the runway a little short of touchdown to account for the flare, but what alternative approaches are there and why would you ever not want/be able to use a stabilized approach?

[Ron 7]

3mpire

I read that the engines were at 50% thrust -- what would be considered idle for a 777?

No, that would be ~ halfway between idle and full.

The question is WHEN were the engines at 50% power? And was that 50% input, or 50% output?

See if they found themselves low, they could of either:
1. Added power to 50%
2. Added full power but the engines only had time to go from idle to 50% before they hit.

"No free man shall ever be debarred the use of arms." -- Thomas Jefferson, Thomas Jefferson Papers, 334

[3mpire 0]

http://www.flightglobal.com/news/articles/crashed-asiana-777-slowed-to-103kt-says-ntsb-388055/

Quote

Deborah Hersman, chairman of the US National Transportation Safety Board, told an 8 July press conference in San Francisco that the aircraft was travelleing at 106kt (196km/h) at time of the crash. However, around three seconds prior to impact, the aircraft reached its lowest speed of 103kt with its engines at about 50% power, although thrust was increasing. Investigations have concluded that both engines were functioning normally, says Hersman.

The aircraft's autopilot was disengaged at about 1,600ft (488m), 82s prior to impact, the flight data recorder shows. Around 73s before the crash, as it passed through 1,400ft, the twinjet had slowed to 170kt and it continued to lose speed on the descent, falling to 149kt at 1,000ft, 134kt at 500ft and 118kt at 200ft.

Thrust was applied as the 777 reached 125ft, with an airspeed of 112kt, 8s prior to the crash, says Hersman.

So according to that at its slowest speed engines were at 50% and went up from there, however it doesn't say if the engines were at 50% for the whole approach.

[Ron 7]

Quote

So according to that at its slowest speed engines were at 50% and went up from there, however it doesn't say if the engines were at 50% for the whole approach.

If they were at 50% that should still be below what is needed for even level flight (I'd need a bunch more info to make a real guess).

But the same concept applies, it takes time for a jet to spool up. So even at 50% power and they realized the mistake and fire-walled the engines.... It is still going to take a few moments for the engines to spool up to climb power, and it is going to take a few moments even after they get climb power to arrest the decent, level off, and start a climb.

The basic operating weight (BOW) depending on the model of the 777 is between 300-370k pounds. Add fuel and PAX (200 pounds average weight used per PAX for W&B) and you have pretty heavy plane you have to change the momentum on.....

307 PAX at 200 and you have 61,400 pounds of people/luggage. If I cared enough, I could run a flight profile to guess about how much fuel was remaining....But we used to use 3k pounds of fuel just to start and taxi to the runway in a DC/MD-10/11.

So you have a very heavy plane and it is going to take power and time to reverse the decent to a climb... They had neither.

"No free man shall ever be debarred the use of arms." -- Thomas Jefferson, Thomas Jefferson Papers, 334

[quade 3]

3mpire

Quote

That's the reason you'd want to fly a stabilized approach in the first place, so you don't have to make drastic corrections.

I know that a stabilized approach is a constant glide angle and speed targeted at a point on the runway a little short of touchdown to account for the flare, but what alternative approaches are there and why would you ever not want/be able to use a stabilized approach?

Well, let's say I'm a flight instructor operating out of a busy airport. There is a jet on five mile final and the controller tells me he can squeeze me in if I make a "short approach," expedite landing and exit the runway at the first taxi-way.

That's not going to be a stabilized approach.

What I might need to do is cut throttle to zero, sideslip and dump flaps over the threshold. Not actually difficult at all, but also not stable at all. The airspeed might increase wildly at first and with the sideslip I might be descending 5,000 feet per minute or more.

This is not, however, how you want to land a large passenger jet if you can help it.

quade -
The World's Most Boring Skydiver

[billvon 2,400]

>why would you ever not want/be able to use a stabilized approach?

For additional reasons google "Kai Tak approaches."

[normiss 622]

To your previous point sir.In Re: culture.

[3mpire 0]

ho leee shit....

[normiss 622]

Huh, wonder why they closed it.

[ryoder 1,384]

Asiana 214 arrives at SFO...again: http://sfist.com/2013/07/09/photo_du_jour_asiana_flight_214_lan.php

"There are only three things of value: younger women, faster airplanes, and bigger crocodiles" - Arthur Jones.

[normiss 622]

Ah so....


That's how it's done!

[sundevil777 93]

Quote

These pilots had to conserve altitude to clear the wall which meant giving up all the airspeed that they could until they had more engine power. They did everything much too late, but dropping the nose would have just killed scores more people.

I think that it is possible that the ideal angle of attack may have been a bit less than what they were at (at least at the min where you get stick shaker, perhaps quite a bit into stick shaker land), but I wonder how easy it would be to find that ideal angle of attack without overshooting to be too shallow and losing more altitude. Perhaps someone knows more definitively where that ideal angle (max lift) would be relative to where the stick shaker starts.

People are sick and tired of being told that ordinary and decent people are fed up in this country with being sick and tired. I’m certainly not, and I’m sick and tired of being told that I am

[sundevil777 93]

lawrocket

Question:

With what we know now, would this qualify as "controlled flight into terrain?"

For military planes (flying super fast and low to avoid radar), instead of terrain following mode, it has been called terrain modification mode.

People are sick and tired of being told that ordinary and decent people are fed up in this country with being sick and tired. I’m certainly not, and I’m sick and tired of being told that I am

[oldwomanc6 38]

sundevil777

***Question:

With what we know now, would this qualify as "controlled flight into terrain?"

For military planes (flying super fast and low to avoid radar), instead of terrain following mode, it has been called terrain modification mode.

Would that also be called "Nap of the Earth?"

lisa
WSCR 594
FB 1023
CBDB 9

[sundevil777 93]

Quote

So even if there is a cultural issue with deference to the person in "command", in this case by total flight hours and the "role" Lee Jeon-min was filling as trainger, he was senior.

I don't know that a cultural deference to authority would apply in this case, as the one who should have spoken up, the copilot, had all the authority he needed to assert himself.

It may have been that the junior pilot was more aware of their bad situation than his trainer, but the cultural issue might still have led to the hesitation in questioning whether a correction was needed. To the knowledgeable pilots of such planes such as twardo's wife, is the pilot flying (pilot in command) normally also in charge of throttles, or is that left to the other?

People are sick and tired of being told that ordinary and decent people are fed up in this country with being sick and tired. I’m certainly not, and I’m sick and tired of being told that I am

[airtwardo 6]

Quote

To the knowledgeable pilots of such planes such as twardo's wife, is the pilot flying (pilot in command) normally also in charge of throttles, or is that left to the other?

I asked the same question a couple days ago...

First ~ was told the PIC is the PIC, the pilot flying is something different & not to be confused.

And 'B' ~ depends on the airline and their training...some have both pilots on the throttles for any changes, some have the flying pilot only...flying pilot can call out for changes.

~ If you choke a Smurf, what color does it turn? ~

[yoink 321]

From the bbc news:

Quote

He [PIC] told the pilot to pull back on the stick, and seconds later he realised that the automated throttle controls, which had been engaged, were not maintaining the correct speed of 137 knots.

http://www.bbc.co.uk/news/world-us-canada-23249012


Too much reliance on automatic systems...

[ChrisD 0]

yoink

From the bbc news:

Quote

He [PIC] told the pilot to pull back on the stick, and seconds later he realised that the automated throttle controls, which had been engaged, were not maintaining the correct speed of 137 knots.

http://www.bbc.co.uk/news/world-us-canada-23249012


Too much reliance on automatic systems...

NTSB just pulls latest U tube vid from their site, they both indicated the pilots statement regarding the Vref speed and the FDR indicating same,...and now they pull the vid????


http://www.youtube.com/watch?v=CqSSrU9L9ok&feature=youtu.be


This is the vid they replaced it with: http://www.youtube.com/watch?v=zZZy_IC06ac

They now explicitly state that they are requesting all approach data for the last few days!

They now also explicitly state that the FDC was coupled...

Gee you guys can't make up your minds, I tell ya about how things actually are in todays world:

That the pilots are required to keep their heads fixed inside...

That the pilots are required to fly all visual approaches with the auto systems engaged...(The NTSB confirmed this)

and now it's too much reliance on automation??????

C

Now here is something else that all of you have ignored about the NTSB:

The NTSB want's to lower the DUI limit...to just one tenth of what it is currently...this means if you have 1.01 of your average beer 8 oz. You will be considered impared, if your about 110 lbs and the sample is taken within 22 min of ingesting same...(Give or take)


That's one beer folks!!!

http://www.youtube.com/watch?v=F36wWX1ZI70

No more beer...

But what do I know, "I only have one tandem jump."

[Rookie120 0]

Quote

I read that the engines were at 50% thrust -- what would be considered idle for a 777?

That is about where flight idle is at. I'm not exactly sure about those engines but on the GE's flight idle is in the 40% N1 range.

If you find yourself in a fair fight, your tactics suck!