Asiana B-777 Reported Down At KSFO

[Don t moderate me this way 882]

So no stock tips ?

 

 

You should have sold Asiana - but now it's too late!   B)

[IAF747 8]

I may be utterly wrong here but the T7 is fly by wire, so actually powering up the engines does not necessarily mean that the pitch changes unless you pull the yoke.

after all they named one of the aircraft (EI EAV) after you, right :-)? just kidding

The pitch of an aircraft is totally different to rate of descent.

 

What happens on takeoff if you pull the yoke before you have no airspeed? Nothing.

 

What happens when you have enough power in the engines to accelerate you to an airspeed where the lift developed by the wings will lift the weight of the aircraft off the ground? You have the lift necessary for when the elevators are in the up position the aircraft will attain a nose up attitude (pitch) and a climb rate (FPM) will be established, which then allows the crew/pilot to retract the landing gear on a positive rate of climb.

 

Basics of flight:

 

 

Lift is the force that directly opposes the weight of an airplane and holds the airplane in the air. Lift is generated by every part of the airplane, but most of the lift on a normal airliner is generated by the wings. Lift is a mechanical aerodynamic force produced by the motion of the airplane through the air. Because lift is a force, it is a vector quantity, having both a magnitude and a direction associated with it. Lift acts through the center of pressure of the object and is directed perpendicular to the flow direction. There are several factors which affect the magnitude of lift.

 

HOW IS LIFT GENERATED?

 

There are many explanations for the generation of lift found in encyclopedias, in basic physics textbooks, and on Web sites. Unfortunately, many of the explanations are misleading and incorrect. Theories on the generation of lift have become a source of great controversy and a topic for heated arguments. To help you understand lift and its origins, a series of pages will describe the various theories and how some of the popular theories fail.

 

Lift occurs when a moving flow of gas is turned by a solid object. The flow is turned in one direction, and the lift is generated in the opposite direction, according to Newton's Third Law of action and reaction. Because air is a gas and the molecules are free to move about, any solid surface can deflect a flow. For an aircraft wing, both the upper and lower surfaces contribute to the flow turning. Neglecting the upper surface's part in turning the flow leads to an incorrect theory of lift.

 

NO FLUID, NO LIFT

 

Lift is a mechanical force. It is generated by the interaction and contact of a solid body with a fluid (liquid or gas). It is not generated by a force field, in the sense of a gravitational field,or an electromagnetic field, where one object can affect another object without being in physical contact. For lift to be generated, the solid body must be in contact with the fluid: no fluid, no lift. The Space Shuttle does not stay in space because of lift from its wings but because of orbital mechanics related to its speed. Space is nearly a vacuum. Without air, there is no lift generated by the wings.

 

NO MOTION, NO LIFT

 

Lift is generated by the difference in velocity between the solid object and the fluid. There must be motion between the object and the fluid: no motion, no lift. It makes no difference whether the object moves through a static fluid, or the fluid moves past a static solid object. Lift acts perpendicular to the motion. Drag acts in the direction opposed to the motion.

 

You can learn more about the factors that affect lift at this web site. There are many small interactive programs here to let you explore the generation of lift.

 

You can view a short movie of "Orville and Wilbur Wright" discussing the lift force and how it affected the flight of their aircraft. The movie file can be saved to your computer and viewed as a Podcast on your podcast player.

From NASA's K12 page here http. www.grc.nasa.gov/WWW/k-12/ airplane/lift1.html

[n4gix 4,947]

I heard on this mornings news that the crew turned off the autopilot and autothrottle systems ~45 seconds prior to the crash.

[mikea76 184]

You should have sold Asiana - but now it's too late!   B)

 

 

LOL!!!!!!!

[IAF747 8]

Not really, because that is actually how all aircraft behave naturally. And if you ever had to get the most performance out of an aircraft on approach, that would be the only possible way to manipulate the controls.

Kevin, you are completely right on this. Rate of descent is controlled with throttles while the speed of the aircraft is controlled with pitch (elevators).

 

In basic airmanship if you approach a stall situation (should never happen to a proficient pilot!) you immediately push forward on the yoke to attain a nose down attitude and increase power to full.

 

That is why wind shear when alerted to it you are slightly higher and faster in descent profile. You can bleed off speed while on the runway and if needed to a TO/GA. much safer than being caught unprepared.

 

What are your thoughts Kevin?

[pinlifter 502]

I heard on this mornings news that the crew turned off the autopilot and autothrottle systems ~45 seconds prior to the crash.

 

 

I also heard that this was the Check Airman's first trip holding that position.  The sink rate, speed and pull up aural warnings had to be going ballistic 

[FLEX1978 373]

I also heard that this was the Check Airman's first trip holding that position.  The sink rate, speed and pull up aural warnings had to be going ballistic

 

I doubt you would have any of those warnings, they flew a flat approach in the last few seconds. Only warning would be a silent SPEED LOW on the EICAS and by the time the stick shaker went off it was too late.

 

Btw just to clarify again, standard procedure on the 777 is AP off AT on whilst on final.

[Steve Dra 7,588]

That's good.  Practice is good, but it does beg one question though.  Does the pilot monitoring at least have the guidance up on his side of the cockpit to keep an eye on how the pilot flying is doing while he is practicing his pure visual approach with a couple hundred people aboard?

 

 

 

It's been very interesting to watch RW ATPs give their differing philosophies concerning the concept of the visual approach, and though my opinion doesn't amount to a hill of beans, I do agree with what Kevin suggests above.

 

If you advocate practicing the visual approach when automated methods are available during a given approach, then you absolutely have one pilot monitoring them on his/her PFD while the approach is flown, with the final authority to command a go-around if he/she feels (or sees via the instruments) the approach has decayed into an unsafe condition.

 

 

Of course in the accident in question, the ILS was inop, so that would not have been an option...however, as anyone who's flown enough (even as a passenger), your body, and your body's mechanisms for interpreting all the tactile, visual, and aural cues are constantly giving you situational awareness enough to realize something is wrong with the approach, most of the time way before the situation decays past the point of no return. Heck if they didn’t, we’d never adjust for a high/low approach and just drive the plane into the ground, right?

 

 

Case in point…I was a passenger on a United 727 into Denver years ago, and I had flown enough to know how a normal approach both “felt” and looked from my vantage point.  As we descended, all appeared normal initially, then my body “felt” like we were a little “mushy”.  I know, not a very technical term, but everyone reading this who has tons of butt-time in an airline seat (and your natural interest in aviation) would have felt the same thing I did. 

 

We were still too high to use the ground as a good visual reference for speed, but I knew at that point I’d be a little more diligent watching this approach.  

 

Sure enough, the closer we got to the ground, the more my fears were coming true…and about the same time I realized this pilot better kick it in the pants, I felt the nose of the plane rising at a rate that was not “normal” to what I was used to.  Sitting in the front accentuated this feeling.  Now the aural cues came into play.  Fully expecting the faint whine of the engines spooling up (remember I’m at the front of a 727), instead I hear to my growing concern, the sound of the wind noise fading from the aural level my ears acclimated to over the course of the flight.  I swear all these cues instantly created a lump in my throat and a knot in my stomach.  I KNEW this was going to be a rough landing.

 

As if all happening in slow motion and at the same time (as you always hear crash survivors say). I grabbed my wife’s hand and told her to hold on!

 

By the time we slammed onto the runway, my last 2 cues that we were going to test the very limits of the 727’s landing gear had come and gone in an instant.  Not really even paying attention to the lack of speed that was obvious from my 3^rd flight that day (gotta love connecting flights), the vision of the aircraft’s shadow rising up to meet me at a rate I had NEVER seen before sickened me.  The aural cue was the sound of the engines throttling to full power.

 

I swear I thought the main struts were going to come through the cabin, and we made 3 landings on that approach   The last “landing” almost seemed like the plane just said “I’m not flying anymore”

 

We all survived, but I’m sure the plane was out of service for a hard landing (hehe 3 of them in fact).

 

 

I won’t speculate on the Asiana accident, but there is no way you can convince me that 2 (or were all 4 up front at the time…not sure) seasoned ATPs could have not felt, saw and heard that the approach was just “wrong” at a point way before they decided to go around. If they could not, then I agree with the general consensus that these pilots have no business in the cockpit.  Sorry, that is just the way it is.  

 

 

The ONLY thing that I can think of that would exclude CREW fault would be windshear at the last moment (since the engines have been ruled out).  

 

Regards,

Steve Dra

[fencer 16]

 Rate of descent is controlled with throttles while the speed of the aircraft is controlled with pitch (elevators).

 

Oh, no...not again please. :LMAO:

 

Daniel, you can control your Cessna any way you want (and it true that pitch for speed is the way a lot of FIs will teach you how to fly).

 

Just be advised that :

 

1 on a jet airliner like the 777,

 

2 in the LANDING mode,

 

3 if you are in full automatic mode,

 

your autothrottle will be controlling speed while pitch will be used to follow the glide slope.

 

Now for airliners landing in MANUAL mode, I THOUGHT most airlines would teach their pilots do do the same (ie throttle for speed and pitch for altitude) but, as we found out some time ago during a long, protracted exchange with Kevin, not all airline pilots on this forum agree... (basically Rón agreed while Kevin disagreed). I must say the two dozen airline pilots I happen to know in real life agree with the throttle for speed method when landing but of course, that's not the whole world.

 

So it is interesting to know that different organisations (the US NAVY beeing one but they have a good reason, they land on carriers on the verge of the stalling speed) will teach you to land using pitch for speed but that - I THINK  - most airlines will teach you throttles for speed.  

 

Apparently, as we learned in this thread, Boeing will let you fly manually with AT on (ie controlling speed if you are in the landing mode).

 

I think since this conversation took place Kevin changed employers so I would be interested in knowing the position of his current airline on the matter.

 

Rgds,

 

Bruno

[yyzflier 11]

Here's a video showing approach to SFO 28L on a severe clear day. 

 

http://www.youtube.com/watch?v=Qf51A_xmF_c&feature=c4-overview&list=UUr8T9rFNMB3tLAW2TSFZc2A

 

Not to make excuses for the crew's inattention to airspeed and the apparent lack of proper CRM, but it's as if they were expecting the autothrottle to manage the airspeed. Could there be a difference in the logic of the B777 autothrottle compared to what he had flown before. 

Or maybe they were so focused on the new pilot's efforts to fly a visual approach, both pilots had their head out of the cockpit and completely neglected to monitor the airspeed. It's a head-slapper for sure. 

[FLEX1978 373]

Bruce, have a read about the FLCH trap. basically if you are desending in FLCH with the Flight directors on & have the MCP altitude below your target altitude, the throttles will remain at idle. You will also have have no speed (wake up) protection once you are below 100ft agl

[bendead 1,085]

Kevin, you are completely right on this. Rate of descent is controlled with throttles while the speed of the aircraft is controlled with pitch (elevators).

 

In basic airmanship if you approach a stall situation (should never happen to a proficient pilot!) you immediately push forward on the yoke to attain a nose down attitude and increase power to full.

 

And you are absolutely right

[yyzflier 11]

Bruce, have a read about the FLCH trap. basically if you are desending in FLCH with the Flight directors on & have the MCP altitude below your target altitude, the throttles will remain at idle. You will also have have no speed (wake up) protection once you are below 100ft agl

 

Thanks. That's interesting. Again, they would have to be completely out of the loop to let speed decay to the extent that it did in this case. But this issue could speak to transition training at Asiana and how pitfalls like this were not flagged to pilots.

By the way, you're not the same Rob Prest who wrote F4 Phantom. If not, I recommend it. Great book. 

[Airbus Commander 563]

after all they named one of the aircraft (EI EAV) after you, right :-)? just kidding

 

:biggrin:

 

A minor point : maybe the word "threat" to qualify a visual approach should have been replaced by another one ("potential risk" ? or "potential threat when not practiced regularly"). And (Ró), to me a threat is not necessarily something beyond my control, it 's just a threat that, with the proper attitude, technique, training - and sometimes luck - I'll be able to overcome.

Rgds,

Bruno

PS (edit) : Rón, what's RHS ? Right Hand Seat?

 

I should clarify here, when I refer to threats that's part of our airline pilot vocab, it's just the word we use to describe something which could cause us an issue during the approach, eg TCAS alert could be a threat when flying into airport ABC.

 

RHS is indeed Right Hand Seat, the Co-Pilots seat.

 

Practice makes perfect. I am just wondering if Ró's is practicing GA anymore

 

I do indeed, I live near to an Airfield and get a nice bit of GA flying in during the summer, typically in a C152 or C172. Never done gliding but would certainly be interested in trying it sometime. On the whole though I'm pretty comfortable in the cockpit of a 152/172.  ^_^

 

Regards,

Ró.

[Airbus Commander 563]

If you advocate practicing the visual approach when automated methods are available during a given approach, then you absolutely have one pilot monitoring them on his/her PFD while the approach is flown, with the final authority to command a go-around if he/she feels (or sees via the instruments) the approach has decayed into an unsafe condition.

 

Just an FYI, in any airline worth it's salt, both pilots at all stages in the approach are allowed to call out "go-around" and the Pilot Flying must go-around first, ask questions later.

 

Regards,

Ró.